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The 7th Editorial Committee Reorganization Meeting of "Urban Rapid Rail Transit" was held

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Research on Key Technologies of Mechanized Shaft Construction in Urban Complex Strata

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o address the issues of low efficiency, significant environmental disturbance, and difficulties in posture control in shaft construction in urban areas with dense buildings and limited space, this study proposes an innovative vertical mechanized construction technology centered on cutting-style shaft boring machines, prefabricated segment structures, and sinking construction methods. The effectiveness of this technology has been verified through its practical application in the No. 2 shaft project from Jingxi Road to Baiyun Dongping Section of Guangzhou-Huadu intercity rail. The engineering practice results indicate that the adoption of undrained excavation with cutting bits and prefabricated assembly technology inside the shaft has significantly reduced the construction difficulty of the retaining structure, minimized stratum disturbance, and improved construction efficiency. The shaft advance tunneling mode can effectively reduce stratum settlement and shear stress. The alternate tunneling mode is suitable for strata with good mechanical properties, while the synchronous tunneling mode is applicable to general strata (including those containing boulders), which can effectively restrain stratum settlement and deformation. Through the optimized design of the drum picks, drum grille and circulation system, the reconstructed shaft equipment demonstrates stronger adaptability under complex geological conditions such as boulder-bearing strata and high-strength rock formations. The research results can provide a reference for the optimization of shaft equipment and construction technology in similar soft-hard alternating granite composite strata.
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Research on the Performance and Application of Full Solid Waste-Based Grouting Materials for Karst Caves in Urban Metro Tunnels

xinhongju, tongjiawen, wangjianhua, zhaiyuanhai, hechen, xiepeng

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When subway tunnels in South China and Southwest China pass through karst areas with developed caves, traditional cement-based grouting materials have high carbon emissions and poor adaptability to karst formations. Additionally, the disposal of solid wastes such as subway shield tunneling muck, slag, and fly ash remains a prominent challenge. This study aims to develop a full solid waste-based geopolymer grouting material to simultaneously address cave reinforcement and solid waste resource utilization.First, single-factor experiments were conducted to determine the optimal parameters of the geopolymer cementitious material: slag:fly ash = 7:3, alkaline activator modulus of 1.3, and alkalinity of 10%. Subsequently, orthogonal experiments were used to obtain the mix proportion of the full solid waste-based grouting material: engineering waste soil:geopolymer = 5:5, quicklime content of 1.5%, and water-to-solid ratio of 0.30. Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS) were employed to reveal the microscale mechanism, and field tests were carried out on the Shenzhen Metro Line 3.The results show that under the optimal indoor mix proportion, the material exhibits a 3-day unconfined compressive strength of 21.71 MPa and a 28-day strength exceeding 29 MPa. Microscopically, alkaline activation promotes the formation of a dual gel system of N-A-S-H/C-A-S-H, which wraps soil particles to form dense aggregates, leading to a significant reduction in the porosity of in-situ soil. In the field tests on Shenzhen Metro, the 28-day core-drilled strength of the material reaches 5.2 MPa, which is significantly higher than that of cement-based grouting materials, and the cave filling effect is excellent.This material can simultaneously consume subway shield tunneling muck and industrial solid wastes, providing a green and efficient solution for cave treatment in subway tunnels in urban karst areas, and possesses comprehensive environmental, economic, and engineering values.
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Spatial Equity of Urban Rail Transit from the Perspective of Service Effectiveness

Tangweiduo, zhangchun

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To address the weak coordination between equity and efficiency rail transit–oriented public transit systems, this study reframes efficiency from operator-oriented technical efficiency to user-oriented service effectiveness, and integrates equity and efficiency under the shared goal of improving residents’ welfare. An accessibility-based equity-efficiency spatial analysis framework is applied to Shenzhen. Results at the subdistrict scale indicate that accessibility in the rail transit–oriented system does not exhibit widespread extreme inequity, underscoring the rail network’s fundamental role in supporting spatial equity. However, the main challenge is the limited alignment between equity and efficiency at the level of service effectiveness. The six area types identified by the equity–efficiency matrix further suggest the need for differentiated, fine-grained optimisation within the existing rail backbone framework. Incorporating efficiency into equity analysis offers new insights for sustainable rail transit equity research.
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Key Technologies Research on Cloud Signal System for Urban Rail Transit

余斌, gaoxiaofei

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With the rapid advancement of urban rail transit construction in China, the networked layout of lines has been continuously improved, and the demand for intelligent operation has been constantly rising. The shortcomings of the existing traditional signal systems in terms of resource utilization and flexible scalability have become increasingly prominent, making it difficult to adapt to the operational requirements of modern urban rail transit, such as high density, high reliability, and efficient operation and maintenance. Based on this, the core purpose of this study is to clarify the development path of the next-generation signal system empowered by cloud platforms, solve the application bottlenecks of traditional signal systems, and provide theoretical support and practical reference for the upgrading and iteration of urban rail transit signal systems. In the research process, a comparative analysis method is adopted to systematically sort out the architectural limitations and usage pain points of traditional signal systems, focus on analyzing the overall architectural composition of cloud-based signal systems, and propose targeted architectural design ideas and key technology application schemes for cloud-based signal systems in combination with the actual operational needs of urban rail transit. This paper conducts in-depth research on the key core technologies supporting the design and implementation of the system, such as cloud-based SIL4 safety technology, vehicle-ground safe real-time communication technology, and adaptation technology between traditional signal business applications and secure cloud platforms. The research results show that cloud-based signal systems can effectively make up for the deficiencies of traditional signal systems, improve the operational efficiency and operation and maintenance level of signal systems, and provide strong support for the networked and intelligent development of urban rail transit. The research conclusions can provide important reference for the design, optimization and engineering implementation of cloud-based signal system schemes, and help promote the transformation of urban rail transit signal systems towards cloudification and intelligence.
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Research on the Construction of Urban Rail Transit Service Guarantee Scheme for Large-scale Events

Liu Lina¹, 王珂, Gao Rong¹

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During large-scale sporting events, urban rail transit systems often face significant pressure in service guarantee, while current service guarantee plans commonly suffer from a lack of standardization, systematic integration, and are often rigid rather than flexible. To improve service guarantee effectiveness, this paper takes the Hangzhou Asian Games and the Chengdu FISU World University Games as case studies, employing a combination of case analysis and systematic research methods to conduct an in-depth analysis of event passenger flow characteristics and corresponding guarantee requirements. Based on this analysis, this paper proposes the construction of a structured guarantee system characterized by a “1 master plan + N special plans” framework with “static architecture + dynamic adaptation” features. It emphasizes maintaining a stable top-level design while dynamically adjusting parameters in special plans to achieve “one plan per day” dynamic adaptability. The study constructs a “passenger flow forecasting-driven, time-space-entity three-dimensional collaborative guarantee model” and designs a standardized four-step formulation process. This provides a theoretical reference and practical guidance for urban rail transit operation enterprises in China to develop scientific, systematic, and highly operable event service guarantee plans.
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Research on Systematic Analysis Methods and Optimization Strategies for Braking System Faults

YANG Haijun, LI Wei, WU Chunhui, ZHANG Haifeng, GUANG Zhirui

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Under high-density operating conditions, single-point failures in metro vehicle braking systems may escalate from equipment-level faults to operation-level risks. Taking an imported braking system applied in the Beijing Metro as a case study, this paper proposes a system-oriented analysis and optimization method for engineering implementation. Based on system decomposition, function–structure mapping, and on-site fault simulation, the propagation paths and amplification mechanisms of key risks—such as exhaust solenoid valve sticking, strong coupling between the main air line and the parking brake, and braking system–TCMS signal interface mismatches—are systematically identified.A combined Failure Mode and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) approach is then adopted to quantitatively evaluate these risks, with the results directly guiding system reconfiguration. Coordinated optimization measures are implemented at the software, pneumatic, and human–machine interaction levels, including an HMI-triggered braking system self-test and self-recovery mechanism, feedforward diagnosis of low brake cylinder pressure, reconstruction of the parking brake air supply using check valves, and an operation-oriented TCMS fault classification and early warning strategy. Multi-line on-site validation demonstrates that the proposed method improves single-point fault identification accuracy by over 34% and reduces emergency handling time by approximately 33%, significantly mitigating operational impacts. The established framework provides an engineering reference for resilience-oriented design and proactive risk management of metro braking systems.
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Spatiotemporal Network-based Study on Passenger-Freight Joint Transportation in Urban Rail Transit

MENG Fanting, CHENG Rubing, LI Xiaojuan, WANG Keyang, GUO Rongge

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The rapid urbanization in China has intensified the imbalance between urban freight demand and supply, which has led to pilot projects integrating express delivery services with urban rail transit systems. This study proposes a collaborative optimization model for passenger-freight co-transportation on urban rail transit lines by analyzing off-peak capacity redundancy and incorporating train carriage allocation and routing decisions for both passengers and freight within a space-time network framework. The bi-objective model, which minimizes passenger waiting time while maximizing transport revenue under capacity and flow balance constraints, employs the epsilon-constraint method to generate Pareto-optimal solutions for analyzing the trade-off between travel time and freight revenue. A case study of Beijing Metro Line 15 demonstrates the model"s effectiveness, showing a 33.68% improvement in transport efficiency and a 47.40% increase in operational revenue, validating its potential for practical implementation.
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An Intelligent Train Control Method Integrating Large Language Models and Proximal Policy Optimization

Kai Gao, Li Zhu, Jia Miao, Lei Liu

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With the advancement of intelligent urban rail transit, automated train operation faces inherent trade-offs between energy efficiency and punctuality, while dispatching regulations are predominantly expressed in natural language and thus difficult to incorporate directly into control modeling. To address these challenges, this paper proposes an automated train operation control method that integrates Large Language Models (LLMs) with Proximal Policy Optimization (PPO). The proposed approach employs an LLM to perform semantic parsing of dispatching rules and operational knowledge, and, under the constraints of a domain-specific knowledge graph, automatically constructs a Markov Decision Process (MDP) comprising the state space, action set, reward function, and safety constraints. Based on the generated MDP, a PPO-based policy optimization framework is developed, incorporating action masking and adaptive reward-weight adjustment to ensure safety while enabling multi-objective coordination. Simulation studies on a representative urban rail scenario demonstrate that the proposed method achieves superior performance in terms of energy efficiency, punctuality, and ride comfort compared with conventional rule-based control, model predictive control, and deep reinforcement learning approaches. The results indicate that combining LLM-based semantic modeling with reinforcement learning provides an effective and deployable solution for automated train operation in urban rail systems.
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Active macro-micro performance regulation method of weakly expansive soils

LU Dechun, CAI Tao, GUO Fei, WANG Guosheng, JIANG Yu, DU Xiuli

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Expansive soils, due to the water sensitivity and lattice swelling characteristics of clay minerals such as montmorillonite, are prone to significant shrinkage and swelling deformations, which seriously threaten the safety and stability of engineering structures such as tunnels, roadbeds and slopes. To address the issues of high energy consumption, high carbon emissions, and insufficient durability in traditional gel-based solidification technologies, this study proposes a method for active performance regulation of weakly expansive soils. By developing a new type of environmentally friendly stabilizer and a cement-lime composite regulation system, the macro- and micro-mechanical properties of weakly expansive soils are dynamically controlled, achieving an overall improvement in their mechanical properties, durability, and environmental performance. Based on a multi-scale experimental approach, it is revealed that the stabilizer, through mechanisms such as ion exchange, gel network formation, physical filling, and skeleton reinforcement, can actively regulate the soil"s microstructure and mechanical properties. The results show that the cement-lime-stabilizer composite system significantly enhances the mechanical properties and durability of weakly expansive soils. The core of this improvement lies in the directional filling of pores and the construction of a three-dimensional network structure by the gel substances at the microscopic level. This research provides theoretical support and a technical pathway for the green and efficient improvement of weakly expansive soils from a chemical-physical collaborative regulation perspective.
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Adaptive embedding decomposition of rail corrugation based on conservation constraints and transient decoupling

Lu Bin, Zhang Jun, Wang Wenhao, Wang Wengang, Chen Xiaoying, Gong Xiao

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To address the limitations of traditional rail corrugation detection methods—such as error accumulation in inertia-based techniques, environmental susceptibility in acoustic and vision systems, and the poor adaptability of data-driven models to nonstationary signals—this study proposes an adaptive embedded multiscale mode decomposition method (AE-MMD) based on conservation constraints and transient energy decoupling. The method constructs a phase-space embedding structure via singular value decomposition, introduces symplectic geometric constraints of Hamiltonian systems to preserve phase-space volume, and achieves structure-preserving mode separation through a joint screening mechanism guided by dominant frequency differences, energy-envelope constraints, and kurtosis modulation. To quantitatively evaluate the algorithmic performance, four metrics are defined: root-mean-square error (RMSE), correlation coefficient (CC), energy leakage rate (ELR), and symplectic preservation index (SPI). In synthetic-signal experiments, AE-MMD effectively separates three typical components—low-frequency modulation, high-frequency carrier, and transient impacts—with an RMSE of 0.2004, CC of 0.9994, ELR reduced to 0.06, and SPI maintained at 1.0. Compared with EMD and CEEMDAN, AE-MMD reduces energy leakage by approximately 68%. In the analysis of measured vibration data from a curved section of the Beijing metro, AE-MMD stably extracts key modal structures dominated by low-frequency slowly varying and modulation components, while mid- and high-frequency components mainly appear in weak and sparse forms. High-energy modes collectively account for approximately 75% of the total signal energy, indicating the method’s strong ability to concentrate energy and separate structural components under complex operating conditions.These results demonstrate that the proposed method achieves high-fidelity decomposition and transient-energy decoupling of nonstationary signals while preserving the underlying dynamical structure. AE-MMD thus provides a new theoretical and engineering framework for early corrugation detection, energy-transfer analysis, and optimization of maintenance strategies.
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Metro Rail Corrugation Identification Method Based on WPD-1DCNN

LIU tiesheng, YU yankun, LIANG junjie, SUN yuexin, HAO jingrong, JIANG chunlei

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In order to achieve accurate and intelligent identification of metro rail corrugation, this study proposes a novel method combining WPD and 1DCNN to identify the rail corrugation. Based on the vertical axle-box acceleration signals collected from in-service metro trains, sixteen sub-band energy features were extracted through a four-level WPD and normalized to construct energy vectors. A lightweight 1DCNN architecture was designed to perform multi-scale feature learning using the energy vectors as inputs. Three corrugation types—no corrugation, shallow corrugation, and deep corrugation—were selected as classification labels for model training and testing. The results demonstrated that, the proposed method achieved an average recognition accuracy of 97.60%, with a recall rate of 100% for shallow corrugation. Compared with SVM, LSTM, and 2DCNN models, the 1DCNN model exhibited higher accuracy and stronger generalization capability. It enables intelligent rail corrugation detection under in-service operating conditions without reliance on specialized inspection systems. The consistency between the wavelength-domain evaluation framework of conventional rail corrugation testing and the identification results of this study was analyzed, and a complementary engineering application workflow integrating online identification with on-site precise measurement was proposed.This study verifies the effectiveness of the WPD-1DCNN fusion method in metro rail corrugation recognition and provides a new approach for online monitoring and intelligent maintenance of track conditions.
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Multi-source Dynamic Scheduling Optimization for Emergency Bus Bridging in Metro Disruptions Using Rough Set Theory

QI Bo, WANG Shengchun, QIAN Mingjun

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To address the issues of low efficiency and resource waste in emergency bus bridging during sudden disruptions of a single metro line, this study proposes a collaborative optimization method integrating dynamic station screening and multi-source dispatching based on rough set theory. First, comprehensive station weights were quantified using rough set theory to identify high-priority stations for bridging services. Second, multi-source transport resources—including reserve buses from depots and in-service buses from regular routes—were integrated to establish a flexible scheduling network. A supplementary station mechanism was simultaneously introduced to mitigate short-term passenger overload risks through flow diversion. An integer programming model was developed with dual objectives: minimizing total emergency bus operating time and minimizing per capita passenger delay time. A hybrid Simulated Annealing Genetic Algorithm (SAGA) was designed for solution optimization. Empirical analysis was conducted using Xi"an Metro Line 5 as a case study. Results indicate that compared with the traditional all-station bridging approach, the proposed model reduces total bus operating time by 28.11% and decreases passenger delay time by 6.03%. When benchmarked against single-source emergency bus deployment, the multi-source strategy yields a 4.13% reduction in operating time and a 39.65% decrease in passenger delay time. This research provides scientific decision support and practical implementation frameworks for emergency bus bridging during urban rail transit disruptions.
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Research on High-Speed Impact Energy Absorption Characteristics and Damage Morphology of Carbon Fiber Composite Laminates for Trains

WANG Lu, LIU Yanwen, ZHOU Kun, YAO Shuguang, ZHOU Minxin, TAN Jingwen

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To address the issue of unpredictable damage to carbon fiber reinforced polymer (CFRP) rail vehicle components due to foreign object impact in the operational environment and to ensure their impact resistance, this study adopts a combined approach of high-speed impact tests and finite element simulation. The methods include: investigating the impact response of CFRP laminates at different impact velocities through high-speed impact tests; constructing a finite element model of the high-speed impact of a projectile on CFRP laminates, using the Chang-Chang failure criterion to simulate interlaminar failure, and verifying the model's accuracy through experiments; exploring the influence of different gradient impact velocities on damage and clarifying the impact response patterns; and simultaneously examining the effects of different projectile shapes and incident angles on energy absorption characteristics and damage morphology. The conclusions drawn are: CFRP laminates exhibit excellent energy absorption stability under high-speed impacts at different velocities; their damage modes are jointly regulated by velocity, projectile shape, and incident angle; the spherical-nosed projectile impact condition offers the best overall performance; and non-perpendicular impacts can enhance energy absorption rate by inducing deflection path damage.
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Dynamic Distribution and Protection Methods of Stray Current with Deterioration of Regional Insulation of Running Rails

duguifu

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Stray current in urban rail transit has become a persistent issue affecting the safety of power supply systems and surrounding underground metal structures. As the scale of rail networks expands and operating years increase, the problem of stray current becomes increasingly prominent. When the deterioration of insulation in the running rail area occurs due to prolonged operation, the distribution and protection of stray current have become a key focus of system maintenance research. Therefore, this paper investigates the dynamic distribution of stray current and the sectional protection method during regional insulation deterioration. A dynamic operation simulation model of the urban rail power supply system under regional insulation deterioration is established, incorporating the characteristics of sectional protection control for comprehensive modeling. The dynamic distribution of stray current along the entire line during regional insulation deterioration is simulated and analyzed, and the control effect of sectional protection on stray current is studied. The results show that regional insulation deterioration leads to rail potential clamping and an increase in stray current in the affected area. Implementing sectional protection, which isolates return current outside the section and employs high insulation within the section, can significantly limit the amplitude of regional stray current. The proposed method can be applied to protect key sections of the line from stray current.
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Research on Intelligent Inspection Methods and Technologies for Urban Rail Equipment Rooms Based on Visual Large Models

YANG Lianbao, MIAO Zhuangzhuang, XIE Xin

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Urban rail transit equipment rooms are critical infrastructure components of urban rail systems, and the stable operation of their equipment directly impacts operational safety and efficiency. To address the limitations of existing intelligent inspection algorithms—such as weak feature extraction capabilities and poor adaptability to multi-source data in complex environments—this paper proposes an innovative intelligent inspection solution for urban rail equipment rooms based on large vision models. Specifically, we adapt large-scale pre-trained vision models to this high-value, niche application scenario, leveraging their powerful general-purpose feature representation and deep semantic understanding capabilities. Furthermore, we design a cloud-edge collaborative architecture: high-precision recognition and model iteration are performed in the cloud, while lightweight inference modules are deployed at the edge to enable real-time detection and fault early-warning. Validated on real-world data from the Dalian Metro Line 1 Dalian North Railway Station equipment room, the proposed method achieves an mAP@50 of 0.923 and an F1-Score of 0.916 in equipment status recognition tasks, outperforming mainstream approaches. Comprehensive cost analysis shows that the system incurs an average annual operating cost of approximately RMB 440,000, yielding an annual saving of RMB 460,000 compared to conventional manual and scheduled maintenance strategies, demonstrating both technical advancement and economic feasibility. This solution not only provides an efficient pathway for intelligent operations and maintenance of urban rail equipment rooms but also holds strong potential for extension to other scenarios such as metro tunnels and stations, thereby contributing to the development of a comprehensive intelligent operations and maintenance system covering entire lines, all equipment, and full-time monitoring.
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Financial Sustainability of Urban Rail Transit with Varying Fare Strategies

DONG Shuyun, LIU Qian, YIN Wei, YAO Ruixiang

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Under the current fare structure, urban rail transit enterprises face limited profitability, and the government is under heavy pressure to provide subsidies，and urban rail transit face significant challenges in financial sustainability. To increase ticket revenue, alleviate fiscal burden, and promote financial sustainability, this paper studies key issues including fare subsidy amounts, adjustment magnitudes, and implementation timing in various cities. By analyzing the domestic revenue and expenditure status of urban rail and comparing fare levels both domestically and internationally, the study reveals the difficulties faced by enterprises in achieving profitability under the government-led pricing model. This paper takes a certain urban rail transit project as an example, establishes a financial modeling framework, calculates the cost-plus fare based on industry average cost and average passenger volume, and proposes a method to define the responsibilities of the government and enterprises based on the cost-plus fare and industry average cost, thereby clarifying the amount of fiscal subsidy required. Further，using Beijing and Ningbo as case studies, the appropriate fare adjustment ranges and timing were explored by considering factors such as the financial capacity of each city, residents' income levels, subway traffic share rate, average travel distances, and traffic congestion. And differentiated fare adjustment strategies are proposed to achieve added value through differentiated services. Additionally, the paper suggests that the state should provide urban rail transit enterprises with high-quality operating assets and resource development policy support to enhance their self-sustaining capabilities and promote the internalization of external benefits. These measures provide a basis for cities to formulate fare adjustment and subsidy plans. The study emphasizes the importance of thoroughly evaluating the impact of fare adjustments on urban development, aiming to establish a fare system that balances enterprise sustainability, passenger affordability, government fiscal capacity, and urban development needs. Ultimately, the goal is to achieve the financial sustainability of urban rail transit.
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Construction Method of Rail Transit Operation and Maintenance Knowledge Graph Based on Large Model

Cui Yulong, Wang Junyan, Chen Jinghao, Sun Kexin

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This paper studies the construction method of rail transit operation and maintenance knowledge graph based on large language model (LLM). With the increasing demand for intelligent operation and maintenance, how to efficiently and accurately build high-quality operation and maintenance knowledge graph has become a key issue. Traditional knowledge graph construction methods rely on manual annotation and complex data preprocessing, which are inefficient and costly. In order to solve this problem, this paper proposes an automated knowledge graph construction method based on large model. The method mainly consists of two parts: 1) Two prompts for rail transit operation and maintenance knowledge graph construction are designed, which are used for domain concept layer generation and data extraction respectively. Through the zero-shot capability of large language model, knowledge graphs that conform to RDF syntax are automatically generated; 2) A knowledge graph construction framework based on these prompts is constructed to convert metadata in the rail transit field into a complete RDF knowledge graph and support integration with existing knowledge graphs. Through experimental verification, the method proposed in this paper shows high accuracy and efficiency in the construction of rail transit operation and maintenance knowledge graph, and performs exceptionally well in low-frequency entity extraction tasks, showing promising application prospects. This method can not only effectively support the operation and maintenance decision-making of the rail transit industry, but also provide strong technical support for the automatic construction of knowledge graphs in other fields. Rail transit operation and maintenance knowledge graph can provide intelligent support for rail transit operation and maintenance, reduce reliance on human experience, enhance response speed and decision-making quality in maintenance, and holds significant engineering application value and promotion significance.
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Research and Application of Multi-level Safety Fusion Control System for Urban Rail Trains

Xia Xisheng, Yang Lijun, Liu Hongjie, Tang Tao, Li Yang, Yu Haoyang

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Against the background of the development of autonomous train operation and virtual coupling, the traditional independent design of vehicle and signaling systems and the distributed control system adopted on the vehicle side have led to problems such as lengthy on-board ATO control links, large response delays, and low control accuracy. This paper proposes a deceleration closed-loop control method based on multi-system integration. In the research process, firstly, a hardware platform and software architecture integrating vehicle control and signaling control functions are designed; secondly, based on this platform, the functional redistribution of the entire process of train automatic operation control is carried out, and the core links such as ATO control, traction/braking force collaborative distribution, and closed-loop control are deeply integrated to reconstruct the control closed-loop; finally, the effectiveness of the method is verified through on-board tests. The test results show that the system can significantly reduce braking response delay and effectively improve the accuracy of braking and stopping control. The research results provide key technical support for the intelligent and autonomous operation of trains in the future.
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Study on Parameter Inversion of the HSS Constitutive Model Based on GA-BP Neural Network

CHEN Junchi, LIU Bo, LI Yongzhi, HE Wencheng, YANG Kai, YAN Qixiang

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To improve the engineering applicability of the hardening soil model with small-strain stiffness (HSS) in numerical analysis of deep excavations for urban rail transit, this study proposes a parameter inversion method combining genetic algorithm (GA) optimization with a back propagation (BP) neural network. A numerical model of a deep excavation, considering the interaction between multilayered soil strata and the retaining structure, is established. Lateral displacement samples are generated through numerical simulations based on uniformly designed parameter sets. Subsequently, a nonlinear mapping between excavation deformation response and key stiffness parameters of the HSS model is constructed by optimizing initial weights and thresholds of the BP neural network using GA. The method is applied to a deep excavation project at a metro station in Chengdu, and inversion results are validated against field monitoring data. Results indicate that the proposed approach can accurately predicts excavation deformations, with numerical outcomes closely matching monitored data and a maximum relative error below 6.3%. The results can provide a reference for selecting HSS constitutive model parameters and predicting deformations in deep excavations under complex geological conditions.
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Research on optimization of crack regulation design parameters of subway tunnel lining

DUAN Xing-ming, ZHANG Zi-hao, YOU Dong-mei, HUI Qiang, CHEN HANG-LING

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To address the issue of crack defects in subway tunnel linings, a safety evaluation criterion based on fracture mechanics is proposed, utilizing the crack tip stability coefficient as an indicator for the structural integrity of cracked linings. Taking the crack remediation project in the Xiaoshizi–Jiaochangkou section of Chongqing Metro Line 1 as a case study, a three-dimensional finite element model was established to obtain the stress intensity factor, crack tip stability coefficient, and mechanical characteristics of the reinforcement materials for each concrete lining structure. Steel belts and steel arch frames were used as reinforcement methods, and the parameters were optimized for the thickness, width, longitudinal spacing of the steel belts, and the model and longitudinal spacing of the steel arch frames. The results indicate that: (1) The crack tip stability coefficient effectively characterizes the tendency of crack propagation. When the coefficient exceeds 1, the crack remains stable, ensuring the safety of the lining structure; conversely, when the coefficient is less than 1, crack propagation occurs, leading to potential instability and safety hazards. (2) Increasing the thickness and width of the steel strips and upgrading the type of steel arches significantly reduce the stress intensity factor, with the crack tip stability coefficient rising from 7.88, 7.25, and 4.78 to 12.81, 15.09, and 13.96, respectively, thereby markedly enhancing the overall stability of the lining. In contrast, increasing the longitudinal spacing of both steel strips and steel arches elevates the stress intensity factor, causing the crack tip stability coefficient to decrease from 14.05 and 5.98 to 3.68 and 1.64, respectively, which diminishes the overall reinforcement effectiveness.
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Statistical Analysis of Urban Rail Transit Operations Worldwide in 2025: A Review

Han Baoming, Zhang Zhi, Feng Fangwei, Lu Fang, Gao Jie, Zou Linhan, Liang Jinfei, Qin Ling, Zhao Lijun, Jin Yuxin

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With reference to internationally recognized statistical standards, this study classifies urban rail transit into three major modes—metro, light rail, and tram. In addition, commuter rail is incorporated to enable a broader-scale assessment of the global operational landscape of urban rail systems and to provide implications for the development of China’s rail transit.The results indicate that by the end of 2025, 562 cities across 79 countries and regions worldwide had opened urban rail transit services, with a total operating length of 46,528.95 km. Among them, metros, light rail, and trams accounted for 48.98%, 13.91%, and 37.11%, respectively. As of 31 December 2025, 65 cities in China (including Hong Kong, Macao, and Taiwan) had operational urban rail transit systems, totaling 13,796.06 km, of which the Chinese mainland accounted for 13,071.58 km.For metro ridership, data from 190 cities in 61 countries show that in 2024 metros carried 76.051 billion passenger trips in total, with an average load intensity of 0.99 × 10? passenger trips/(d.km). In China (including Hong Kong, Macao, and Taiwan), metro systems carried 33.541 billion passenger trips in 2024, representing 44.10% of the global total. Overall, China’s urban rail transit has continued to expand steadily, ranking first worldwide in both network length and passenger volume.With respect to commuter rail, 241 cities in 54 countries and regions had opened commuter rail services by the end of 2025, with a total operating length of 70,001.16 km. In China (including Hong Kong, Macao, and Taiwan), 31 cities operated commuter rail with a combined length of 4,345.73 km, accounting for 6.21% of the global total. These figures suggest that, as China enters the 15th Five-Year Plan period, there remains substantial scope to further improve the overall scale and network structure of commuter rail development.
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Composites Track Intelligent Mobile Inspection System Based on Multi-level Distributed Technology

ZHAN Yi, ZHAO Qianying, XU Hu, TANG Pei

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Aiming at the problem of limited installation space of traditional integrated inspection beam in track inspection system, a track intelligent mobile inspection system based on multi-level distributed technology is proposed. The system adopts synchronous triggering technology, combined with alignment mathematical model and image splicing algorithm, which effectively solves the problems of difficult image acquisition of track and poor data alignment accuracy. In order to enhance the recogntion accuracy in the track inspection system, the network is reconfigured. By introducing the Squeeze-and-Excitation attention mechanism module to enhance the feature extraction capability of the network for structural components such as rails, fasteners, and roadbeds. Timely detection and localization of electric buses under operating conditions is achieved. Through the installation and testing in Beijing Metro Line 2, it can be found that this system can reduce the installation space by 40% compared to traditional methods, and the installation time is greatly reduced from 3 days to 4 hours. In terms of detection performance, the average mean precision of 12 common types of track defects reaches 95.2%, and the positioning accuracy is controlled within ±1 meter. This system is able to discover track defects and warnings in time, effectively improve the safety level of rail operation, and provide a practical solution for intelligent inspection of rail transportation.
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Cultural Characteristics and Vitality of Metro Station Names in Chengdu

Rong Junjie, Xie Ping, Wan Long, Lan Yutong, Hu Yanlan

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Addressing the lack of systematic quantification of the cultural functions of metro station names, this study develops an integrated evaluation framework that combines toponymic classification, spatial analysis, and POI‐based big-data mining. Using Chengdu as a case, we assess cultural expression, spatial configuration, and contemporary vitality of 364 station names. The toponymic analysis shows that Chengdu’s metro nomenclature synthesizes multiple cultural lineages—Shu civilization, the Three Kingdoms, water engineering, marketplaces, traditional commerce, and migration—forming a diversified cultural atlas. Kernel density analysis reveals that cultural station names are clustered in the central city yet exhibit a weak spatial correspondence with high-density zones of historical place names. POI-based vitality metrics indicate that cultural station names are, on average, more vibrant, while a non-negligible subset associated with important historical memories displays markedly lower vitality. The proposed framework quantitatively surfaces the risk of cultural memory marginalization and provides an operational, data-driven basis for shifting urban governance from passive name retention to proactive cultural asset activation. The approach is transferable to other cities undergoing rapid urbanization, enabling comparative audits of how metro naming mediates between heritage transmission and contemporary urban dynamics.
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Track geometry extraction method based on point cloud fine model

LI Haiyan, SI Jiangmin, WEI Guanjun, WU Zhicai

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To address the challenges in extracting track geometry parameters, this paper proposes a method based on a refined point cloud model. First, the point cloud data is optimized using mesh upsampling and an improved farthest point sampling (FPS) method to obtain data better suited for model reconstruction while ensuring uniformity and feature integrity. Next, an enhanced greedy projection triangulation algorithm is applied to construct the track model. Finally, track geometry information is extracted from the refined model. The experimental results show that: In the orbit model constructed after optimization by the proposed method, the proportion of triangular mesh point angles between 50 and 70 degrees increases from 66.25% to 81.03%, the information entropy of the orbit model increases from 2.7992 to 3.3219, and the Hausdorff distance from point to plane decreases from 0.9037mm to 0.7564mm. The proposed method is proved to be highly accurate and reliable in model reconstruction. When track model is used to extract track information, the overall trend error of a single track is 0.2mm, and the average error of track spacing is 0.61mm. These results validate the feasibility of using the refined model for track geometry extraction, providing reliable data support for future track deformation monitoring and digital twin applications in rail environments.
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Global Optimization of Cross-Line Train Timetabling in Urban Rail Transit Systems For Engineering

dongqiuhan, Tang Jinjin, LI Chao, Shao Xinyun, Li Jian, 梁蒙垚衡, 刘思东

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This study addresses the challenge of balancing vehicle turnover efficiency, train load factors, and operational economy in cross-line operations from the perspective of urban rail transit operation enterprises. It constructs a multi-dimensional collaborative optimization model with the core objective of minimizing operational train-kilometers. Focusing on the economic optimization of spatiotemporal resource allocation, the model integrates key elements such as timetable scheduling, turnaround operations, depot plans, and cross-line sequencing. It innovatively establishes a linkage constraint mechanism between the maximum headway and passenger flow load factor to achieve coordinated management of operational costs and service reliability. To enhance solution efficiency, the Fast Solution Algorithm for Engineering-Cross Line Operation (FSAE-CLO) is proposed, which employs an iterative probability optimization framework to compress the solution space. An empirical study using the morning peak hours of Beijing's Fangshan Line and Line 9 demonstrates that, compared to the single-line operation mode, the proposed scheme reduces train-kilometers by 6.83%. Furthermore, it achieves an additional 4% reduction in operational mileage and a 24% shortening of solution time compared to a genetic algorithm. This research provides theoretical methods and practical engineering support for enterprise-level cross-line operations, and its resource coupling optimization mechanism offers significant reference value for enhancing the efficiency of network-wide operations.
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Overview of urban rail transit operation lines in Chinese mainland in 2025

HouXiufang

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The year 2025 marks the concluding year of the 14th Five-Year Plan period. By the end of this period, mainland China will have 28 provinces and 58 cities with 382 urban rail transit operating lines, totaling 13,071.58 kilometers in length. Among these, subway lines account for 1,007.06 kilometers, representing 76.56% of the total. By the statistical period, 1,976.41 kilometers of fully automated operating lines had been opened, accounting for 15.12% of the total operational mileage. In 2025 alone, 55 new urban rail transit operating lines (segments) were added, with a total new operational length of 910.80 kilometers. This includes 700.97 kilometers of new subway lines and 491.99 kilometers of new fully automated operating lines. It is projected that approximately 4,000 kilometers of new urban
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Auto-optimization of Equipment Layout for Metro Station Environmental Control Equipment Room Based on the Gravity-Repulsion Model

LIU Moyun

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It is a significant challenge for space optimization in subway station environmental control rooms driven by cost-efficiency objectives. Due to the limited space of the metro station, the environmental control equipment room usually contains multiple equipment of the system, which leads to the challenge of reasonable layout. To effectively utilize the space of the environmental control equipment room, an auto-optimization approach is proposed in this article to optimize the layout of central chiller plants. A repulsion model is adopted herein to quantify the rationality of equipment layout, which is regarded as the optimization objective. Differential evolution algorithm is utilized herein to adjust the equipment layout within a given space for the lowest optimization objective. Moreover, this approach repeatedly reduces the given space to minimize the space occupation of the central chiller plant.
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Key technologies of urban express line transportation organization for rapid arrival -Taking Chengdu Rail Transit Line 19 as an example

Zhao-Yi, Xiang-Hong

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For the metropolitan express line serving the connection between commuting and hubs in the metropolitan area, ' fast arrival ' is its core service goal and core competitiveness, which is directly related to the service level of the line and the attractiveness of public transportation. Under the dual airport pattern of " one city and two airports " in Chengdu, Chengdu Rail Transit Line 19, which needs to achieve " rapid arrival of dual airports in 30 minutes, " is the ultimate case of rapid arrival of urban express lines. Taking Chengdu Rail Transit Line 19 as an example, this paper deeply analyzes the key technologies of train operation organization adopted in order to realize the rapid arrival between the two airports in the face of the 66.7 km operating distance between the two airports and its composite function positioning : 1 ) Complete the design of the ' one-line dismantling and three-line through operation ' train operation organization scheme between the three rail lines of Line 17, 18 and 19 to ensure the feasibility of direct train operation between the two fields ; 2 ) The maximum running speed of the city AC A train is increased from 140km / h to 160km / h, which creates better conditions for the realization of dual airport direct 30min ; 3 ) In order to keep the direct train running at a high speed, the speed of the direct train is increased to 160km / h, and the No.42 turnout is introduced.Based on the systematic review of the above technological innovations, this paper summarizes five key design inspirations for the rapid arrival transportation organization of urban express transportation organization : 1 ) Planning and layout in advance to ensure cross-line operating conditions ; 2 ) Unified scheduling of cross-line operating lines ; 3 ) New ideas for the application of city A vehicles to speed up ; 4 ) The speed of the express train has the conditions to improve ; 5 ) Turnout No.42 is carefully introduced into underground engineering. This paper can provide reference for the follow-up design of urban express transportation organization with fast arrival demand.
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Research on Fast Protection and Fault Isolation Method for Medium-Voltage Ring Network in Urban Region Railway Based on Load Switches

ZHANG Chutian

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In response to the problem of insufficient speed caused by step-by-step coordination in traditional time-limit overcurrent protection for medium-voltage ring networks of urban region railway based on load switches, this paper proposes a fast protection method based on differential current. The fault section is identified by using the fault characteristics of differential current, and the fault information is transmitted to the master station via the GOOSE network. The master station then controls the tripping of the outgoing circuit breaker at the power distribution station to achieve rapid fault clearance. At the same time, the outgoing current of the substation is monitored. When the outgoing current drops below a threshold, a command is sent via the GOOSE network to control the tripping of the load switches on both sides of the fault section, completing the fault isolation. After fault isolation, the circuit breaker at the substation outgoing line and the open loop point are closed to restore power supply to the healthy area. Simulation results show that under different fault types, locations, and transition resistances, the proposed method can achieve rapid protection operation and effective fault isolation, significantly improving protection rapidity and providing a reliable guarantee for the safe and stable operation of the medium-voltage ring network in urban region railway systems based on load switches.
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Analysis of Differential Deformation Characteristics in Variable Cross-Section Metro Tunnels Induced by Asymmetric Backfill Loading

guojin, jiaobenkang

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Surface surcharge can induce certain deformations in metro tunnels, and excessive deformation may compromise the safe operation of the tunnel. To investigate the impact of asymmetric surface fill on variable cross-section metro tunnels, this study takes a road backfilling and reconstruction project adjacent to an underground section of Shijiazhuang Metro as the background. Finite element models of both horseshoe-shaped and rectangular (box-shaped) tunnel cross-sections were established to analyze ground surface settlement and the deformation and stress characteristics of the tunnel structure during road backfilling construction. The numerical results were validated against field monitoring data. Furthermore, the influences of key parameters—including tunnel burial depth, surcharge magnitude, and surcharge dimensions—on the underlying variable cross-section tunnel were systematically examined. The main findings are as follows: (1) Under asymmetric surcharge loading, the displacement field of the ground surface approximately exhibits a “V”-shaped settlement profile. The maximum surface settlements above the horseshoe and box tunnel sections are 15.85 mm and 27.17 mm, respectively. Tunnel deformation is predominantly vertical, with relatively minor horizontal displacement. Compared to the horseshoe-shaped tunnel, the box-shaped tunnel is more significantly affected by surface surcharge. (2) A noticeable discontinuity in deformation occurs at the junction between the horseshoe and box cross-sections, indicating that cracking and water leakage at this transition zone require close monitoring during construction. (3) The magnitude and extent of surcharge are positively correlated with tunnel vertical settlement, whereas the horizontal offset between the surcharge centerline and the tunnel axis, as well as tunnel burial depth, are negatively correlated with settlement. The surcharge width significantly affects the spatial distribution of tunnel settlement. When the tunnel burial depth exceeds 24 m or the horizontal offset between the surcharge centerline and the tunnel axis exceeds 50 m, the influence of surface surcharge on tunnel settlement becomes negligible. These findings provide valuable references for similar engineering projects.
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Research and Practice on Evaluation of Artificial Intelligence Large Models in the Field of Urban Rail Transit

HUA Fucai, Shao Xin, Xia Xiujiang, HAN Xiaoyi, WANG Wenjun, YU Songwei

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With the rapid development of large AI model technology, the demand for the application of large models in the urban rail transit field is growing increasingly. However, there is still a lack of evaluation standards and methods for large models specific to the urban rail transit industry. To address this, this paper establishes a set of evaluation systems for large models in the urban rail transit industry. This evaluation system covers the construction of evaluation datasets, the design of evaluation dimensions, the selection of evaluation methods, and the formulation of evaluation metrics. Through this system, the performance of urban rail transit large models in tasks such as language understanding, knowledge reasoning, image-text alignment, and spatiotemporal consistency is evaluated comprehensively and objectively. Meanwhile, a dedicated evaluation system for large models in the urban rail transit field is designed and developed, and the effectiveness of the evaluation system is verified through practical applications. The verification results show that the established evaluation system can provide an evaluation basis for the optimization and application of large models in the urban rail transit field, and promote the implementation and application of large models in the urban rail transit industry.
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Applied Research on Dynamic Thermal Environment Management System for Subway Stations

wei ting san, 顾浪腾, li zheng jie, 张壮飞, 杨家亮, shi wei shi

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With the rapid development of urban rail transit, the thermal environment management of subway stations, as densely populated public spaces, is crucial for passenger comfort and system energy efficiency. This study constructs a dynamic thermal environment management system for subway stations based on spatial grid-based monitoring, CFD numerical simulation, and device linkage control, addressing the unique thermal characteristics of these environments. The effectiveness of the system in enhancing passenger comfort, reducing air conditioning loads, and achieving energy-efficient operation is verified through an application case at Nanning Metro Line 1 Nanhu Station. The results show that the system maintains a good thermal comfort state when the ambient temperature is increased to 29°C, with an energy-saving rate of over 32.1%. This provides a scientific basis and practical reference for the green energy-saving transformation of subway stations.
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Research on coordination evaluation of Jinan rail transit stations and regions from the perspective of “node-place-vitality” three-dimensional model

ZHAO Jinbao, ZHOU Qi, ZHOU qi, HOU Keke, LI Mingxing, LIU Wenjing, JIANG Jiawei

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In view of the limitations of the two-dimensional perspective of the traditional node-place model in complex urban environments, this study constructs a three-dimensional "node-place-vitality" model. With 41 stations of Jinan"s rail transit as the research subjects, a service radius of 800 meters around each station is demarcated. Twenty-four indicators are selected from three dimensions: traffic function, urban space, and dynamic vitality. The comprehensive subjective-objective weighting method and K-means clustering analysis are employed to analyze the coordination of station areas. The results indicate that the three-dimensional model can effectively uncover the synergistic relationships among nodes, places, and vitality. Moreover, the stations are classified into five types: high-vitality hub stations, vitality-improvement stations, balanced-development stations, node-reinforcement stations, and comprehensive-cultivation stations. Their spatial distribution is highly associated with the development characteristics of Jinan"s main urban centers, sub-centers, and marginal areas. This research offers a scientific foundation for the optimization of Jinan"s rail transit station areas and the formulation of TOD strategies. Additionally, it provides a novel perspective for studies on the coordination of station areas in similar cities.
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Research on the Equity of Bike Sharing Use in Metro Catchments:A Case of Shenzhen

GUO Yuanyuan, TANG Fengliang, zhang runbin, ZHANG Longhao

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With the increasingly prominent role of bike sharing in the "last mile" of urban transportation, the issue of service equity has attracted extensive attentions. Based on the data of shared bike usage and passenger flow of metro stations in Shenzhen in August 2021, this research evaluates the equity characteristics of bike sharing services in Shenzhen metro catchments (within the range of 15-minute cycling circle) and analyzes its spatial pattern and time differences. By constructing two types of indicators, namely the Gini coefficient of per capita bicycle use, and the Gini coefficient of supply and demand matching, the imbalance in the use of bike sharing in space and crowd was quantified. A higher Gini coefficient indicates a greater degree of inequity across spatial and demographic dimensions. The results show that there is a certain inequity in the use of shared bicycles in Shenzhen, and there are significant differences in different time and space. The distribution of shared bicycle use in the central urban area is relatively balanced, and the use of bicycles in the suburban new city is highly concentrated. Some metro lines (such as those connecting the central urban area and the outer new towns) have significantly lower levels of bicycle use fairness than those in the central area. Bike sharing usage is closer to the distribution of commuting demand during the morning and evening rush hours on weekdays, while there is a mismatch between supply and demand during weekends. Finally, based on the results, this paper raises targeted recommendations for optimizing the layout and scheduling of bike sharing in metro catchments to improve the equitable accessibility of metro shuttle bike services.
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Research on multi-dimensional data acquisition scheme of urban rail train maintenance robot based on vision

ZHU Jiangyong, ZHAO Xiaodong, WANG Yudong, SUN Peng, CHEN Mijie, LI Xiang

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Regarding the current situation where there is no unified industry standard for urban rail maintenance robot data collection schemes, the cycle for robots to obtain effective train component image data is relatively long, and the types of component image data acquired are limited, making it difficult to effectively identify train air leakage and abnormal temperature faults.This paper discusses the research on the multi-dimensional data acquisition scheme of urban rail maintenance robots to improve the deployment efficiency of robot projects and obtain multi-dimensional fault data types. In the fixed trench of the subway maintenance garage, taking the 6-group B-type cars with different car numbers as an example, the multi-dimensional train data acquisition scheme construction test was carried out by using the end camera, acoustic camera and thermal imaging camera of the robotic arm, and the multi-dimensional data acquisition scheme was theoretically guided by the safety of on-site personnel and equipment as the benchmark, and the overall deployment efficiency of the overhaul robot and the final imaging effect of the camera were taken as the evaluation criteria.The experimental results show that after the construction of the multi-dimensional data acquisition scheme, the type of fault data that can be detected is increased by 2 times, the number of detectable items is greatly increased, the data acquisition cycle of 6-group vehicles under the same trench is shortened by about 50%, and the proportion of unreasonable image data collected by the terminal camera is reduced to 5.25%. Collaborative verification of multi-dimensional camera data effectively prevents fault misidentification. It provides data reference for the promotion of maintenance robots in the field of smart urban rail.
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Research on Tunnel Core Soil Monitoring Technology Leveraging YOLO-Based Visual Recognition?

lvpeiyin

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In drill-and-blast tunnel construction, the geometric configuration and retained dimensions of the core soil directly influence tunnel settlement magnitude and surrounding rock stability. Traditional manual monitoring methods are inherently subjective, inefficient, and fail to meet real-time monitoring requirements. This paper proposes an automated core soil monitoring method based on an improved YOLO framework. By defining core soil feature points, a standardized annotation system is established. A lightweight detection model incorporating the Convolutional Block Attention Module (CBAM) is designed, effectively suppressing false detections caused by uneven illumination, dust interference, and blurred soil boundaries. Integrated with perspective geometry vanishing point prediction techniques, the VPTR model is employed for vanishing point detection and geometric constraints. This approach corrects perspective distortion errors in core soil cross-section shape calculation, incorporates core soil dimensions and proportions into potential risk classification criteria. For engineering deployment, knowledge distillation and dynamic precision-switching techniques are adopted to enable lightweight operation on edge computing devices, supporting the real-time decision-making demands of "monitoring while excavating".
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Experimental Evaluation of Mechanical Properties and Vibration Damping Performance of Steel Spring Floating Slab Isolation Systems for Existing Subway

WANG Ruiji, YU Huali, TIAN Zhiyong, LI Chaohua, HUANG Wenbo, LIAO Yujie

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To investigate the mechanical and vibration damping performance of existing subways after a certain period of operation and evaluate their continued service capability, this study focuses on the floating slab system of Chongqing Rail Transit Line 1 after eight years of operation. Through train vibration testing, the natural frequency and damping ratio of the current floating slab system were measured and analyzed. Vibration damping performance tests were conducted on both floating slab tracks and conventional tracks to compare their vibration damping effects. Furthermore, steel spring isolators were extracted for fatigue testing to investigate how isolator stiffness, damping ratio, and height change under fatigue loading. Results indicate that the natural frequency and damping ratio of the current floating slab system's remain within reasonable ranges. Compared to conventional tracks, the floating slab track absorbs substantial vibration energy by increasing its own vertical acceleration, thereby reducing vibration interference from subway operations to the environment and meeting vibration reduction requirements. During 3 million fatigue cycles, changes in isolator stiffness, damping ratio, and height remained below specification limits. No cracks were observed in the steel springs or sleeve welds, and no leakage occurred in the damping material. Comprehensive evaluation indicates that the mechanical and vibration damping performance of this floating slab system continues to meet design requirements, suggesting they can continue to operate reliably and possess a prolonged service life.
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Subway Station Entry Passenger Flow Prediction based on Hybrid Deep Learning Method

LI Changlong, YANG Xiaoxia, ZHANG Guoqing, CUI Chunyue, WAN Jiahui

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To address the critical challenge of predicting passenger flow at subway stations, this study introduces a novel hybrid deep learning method, AFT-K-GRU, designed to enhance decision-making support for subway operations management. Leveraging the multi-scale temporal dependencies inherent in subway passenger flow data, the model innovatively integrates three core components: the Attention-Free Transformer (AFT), Gated Recurrent Unit (GRU), and Kolmogorov-Arnold Network. Specifically, the AFT module captures the long-term periodic patterns in passenger flow data, the GRU network focuses on extracting short-term fluctuation characteristics, and the Kolmogorov-Arnold Network serves as a nonlinear mapping layer, replacing traditional fully connected networks to enhance the model"s expressive capacity. Experimental validation using real-world card swipe data from Beijing subway stations demonstrates that the AFT-K-GRU model effectively predicts station passenger flow, achieving error reductions of 14.4% and 16.0% compared to GRU and LSTM methods, respectively. This model offers effective methodological support for subway operators, assisting management departments in passenger flow control and daily planning, thereby enhancing the operational efficiency and service quality of subway lines.
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Optimization Strategy of Polycentric Urban Rail Transit System Based on PTAL Model——A Case Study of Dongguan City

CHENG Jiankai, LU Jianbo

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To promote the coordinated development of urban rail transit with urban spatial layout, population and employment distribution, and public service facilities, this paper constructs a multi-dimensional PTAL quantification model that integrates urban rail transit and conventional bus services based on a comprehensive urban transportation model. This model is used to systematically evaluate the public transport accessibility within the Dongguan metropolitan area. The study reveals that the current PTAL level in Dongguan is generally low, with average accessibility index ratios for the central urban area, sub-centers, economically strong towns, and ordinary towns recorded at 3.6:0.8:1.2:1. This indicates a spatial pattern characterized by "single-core polarization, small-scale decentralized clusters in peripheral areas, and homogeneous fragmentation in the remaining regions." The findings highlight several issues, including a disconnect between public transport resource allocation and the polycentric structure, a lack of synergy between urban rail transit and bus services, and a mismatch between public transport resource provision and the distribution of population and employment.The research demonstrates that by establishing a network of urban rail transit express lines and strengthening public transport services in underdeveloped areas, the overall public transport accessibility in the metropolitan area could increase by 65.3%. Notably, sub-centers such as Songshan Lake and Binhaiwan could experience an improvement of up to 153.6%, significantly reinforcing the polycentric structure defined as "one primary center, two sub-centers, and six clusters." Furthermore, optimizing bus connections at urban rail transit stations and coordinating the layout of public facilities can enhance the alignment between rail transit resources and the distribution of population and public services. Ultimately, this study provides technical support for establishing an integrated "rail transit + bus" system to advance polycentric development in Dongguan.
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Optimization Strategies for Small-radius Curves at Platform Ends

liangchuangjia, 任祥, QIU Gangyuan

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With the rapid urban development and the advancement of urban rail transit construction, the routes of newly built rail transit projects are becoming increasingly complex. The phenomenon that the transition curve intrudes into the end of the effective platform at the stations in the central urban area is inevitable. Aiming at the problem that the excessively long intrusion length of the transition curve into the effective platform restricts the maximum speed limit of the curved route, in order to improve the train operation speed and shorten the whole-line travel time, this study deeply analyzes the influencing factors of the intrusion length of the transition curve into the effective platform, as well as the allowable intrusion length. On this basis, three innovative optimization schemes are proposed to increase the curve superelevation, and thus improve the maximum speed limit of the curved route. These schemes are respectively: setting the superelevation gradient rate of the transition curve in sections, reducing the length of the transition curve, and reducing the curve radius. Through comprehensive comparison and analysis, and combined with practical engineering cases, the conclusion is drawn that: under the premise of meeting the specification requirements, the scheme of reducing the curve radius is preferentially recommended; while in the sections where the engineering conditions are limited, the schemes of setting the superelevation gradient rate of the transition curve in sections and reducing the length of the transition curve can be considered.
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Research on dynamic warning system for anti floating failure of subway structures

Liang Zhongdong, Li Zhibin, Guan Qifeng, Zhang Yue, Shan Yepeng, Cai Guoqing

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Groundwater level fluctuation is crucially linked to the stability and safety of subterranean constructions. This paper utilises the descriptive statistics methodology to categorise the underground infrastructure in Beijing. The theory of combining the effective stress method based on absorption stress and Mohr-Coulomb model is applied to construct a numerical model in order to analyse the pattern of structural stress and displacement. Ultimately, the numerical simulation database is composed, and the dynamic early warning system of anti-floating failure is established. The findings indicate that: The numerical simulation database has a broad range of applications and can accurately demonstrate the decline in base bearing capacity post-water level rise. Building dynamic warning indicators for anti-floating failure using the numerical simulation database enables an integrated reflection of the structural stress and displacement patterns. To ensure the safety of tunnel structures and passengers in the face of changing groundwater levels, a standard of judgement and safety warnings must be established. The water relief and decompression method should be used as a warning response, with pressure relief serving as the primary action for early warning response. This approach enhances the effectiveness of early warnings. This warning system has the potential to establish a robust technical basis for proposing strategic measures to sustainably develop major metro projects. It holds crucial academic and practical value for ensuring the secure operation and maintenance of metro projects.
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Vulnerability Assessment Method for Metro Stations to Rainstorm Waterlogging Based on the DPSRC Model

Zhao Jingya

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To address the high risks faced by metro systems due to their enclosed underground spaces, vulnerable facilities, and structural complexity amidst frequent rainstorm waterlogging, it is imperative to develop a scientific vulnerability assessment method for metro stations to enhance comprehensive resilience. Based on the "driver-pressure-state-response-control" chain analysis framework of the DPSRC model, this study systematically analyzes the dynamic causality of metro rainstorm waterlogging risks. An assessment index system comprising 5 criterion layers and 20 indicator layers was constructed. By integrating subjective and objective weights using the AHP-entropy weight method, a comprehensive vulnerability assessment approach for metro stations was proposed and applied to an empirical analysis of 99 stations in the Ningbo Metro. The results indicate that: ①The proposed method can accurately and effectively assess station vulnerability; ②Stations vulnerability exhibit an asymmetric distribution across high (19.10%), medium (51.69%), and low (29.21%) vulnerability levels, with 70.79% of stations exposed to risk, highlighting an urgent need for systemic prevention and control; ③Waterlogging prevention capacity, monitoring and early warning capabilities, and emergency equipment reserves constitute the key contributing factors to high-vulnerability stations. This research provides a reference for rainstorm waterlogging risk management, disaster prevention, mitigation planning and resilient transportation development in urban metro systems.
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Multi-dimensional Passenger Flow Characteristics and Enlightenment of Wuhan's Urban Rail Transit Network

Wu Ningning, Wang Dong, Li lingqi, Gao song, Xiao Yiying, Gao Wencan

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To address low passenger flow efficiency in mega-cities' urban rail transit networks, this study takes Wuhan as a case, develops a multi-level framework to explore flow formation mechanisms, and proposes refined enhancement and prediction strategies. By comparing flow evolution across network stages, it reveals diminishing marginal benefits in flow growth, analyzes spatiotemporal characteristics at multiple levels, and identifies formation rules via correlation analysis. Based on the findings, a tiered strategy of “intensifying core, optimizing center, and cultivating periphery”is proposed, along with an optimized forecasting system that integrates macro multi-scenario prediction, corridor identification, and full-cycle dynamic calibration. The framework provides systematic technical support for alleviating insufficient passenger flow and resource mismatch, offering practical value for sustainable urban rail transit development.
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Integrated Optimization of Train Operation Adjustment and Speed Management Considering Energy Saving

YUAN Ye, SHI Lingyuan, YANG Xin

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To address train rescheduling and speed management under disruptions for urban rail transit, this study constructs a mixed integer nonlinear programming (MINLP) model with decision variables including train running times, acceleration times, extra dwell time and disruption impact status, aiming to minimize train traction energy consumption and terminal arrival delay times, thereby enabling rapid optimization of train rescheduling and energy-efficient speed profiles and ensuring the safe and stable operation of urban rail transit systems. Considering the quadratic non-convex constraints in the model, we reformulate the MINLP into a mixed integer quadratic programming (MIQP) model through Taylor approximation method, enabling effective solutions via commercial solvers. Utilizing operational data from Beijing Subway Yizhuang Line, numerical experiments validate the effectiveness of the MIQP in reducing train terminal delay time and traction energy consumption. This research provides theoretical foundations for rail transit operators to optimize train dispatching and operational control during disruptions.
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Research on the Intelligent Dispatching Decision Generation Model for Urban Rail Transit Based on Eventic Graphs

zonghuixi, baili, yankaiming

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To address the challenges in urban rail transit emergency response, such as over-reliance on manual experience, poor dynamic adaptability, and low efficiency in decision-making. This paper proposes a generation model for emergency decision-support that integrates a predicate-centric event representation framework with an Event Evolution Graph-RAG architecture. The core innovation lies in employing non-static triggers to structure emergency disposal processes, surpassing static knowledge graphs. Through strategies like information-group situational assessment and a two-stage “event-situation” query rewriting, the model enhances traditional RAG with improved logical comprehension of event chains, thereby producing more operable and context-aware emergency decisions. Evaluated via decision compliance rate, generation time, and efficiency improvement. Experiments show that the proposed model achieves 84.74% accuracy in decision logic and raises efficiency by 57.14% compared to conventional manual approaches, while maintaining high compliance and reducing response time, offering a reference for building intelligent dispatch decision-support systems.
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Research and Application of Shield Tunnel Deformation Correction Using the Adaptable Reinforcement Method with Radial Cement-Soil Piles

caizongyang

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Addressing the challenge of managing excessive deformation diseases in operational shield tunnels in China, this research employed various methods to tackle key technological issues. It innovatively developed a comprehensive correction technology system centered on the Adaptable Reinforcement Method with Radial Cement - Soil Piles. Through a series of technical measures, including the construction of a spatial mesh reinforcement body, the formulation of construction sequences and control strategies, and the derivation of estimation formulas, this system has achieved remarkable results: a settlement correction range of 15% to 45% and a convergence correction range of 5% to 40%, while simultaneously significantly reducing leakage diseases. This technology system was validated through application in a subway interval tunnel project in Northeast China.The application results demonstrate that the Adaptable Reinforcement Method with Radial Cement - Soil Piles can synergistically correct both settlement and convergence issues, effectively stabilize the post - construction settlement rate, and notably improve leakage conditions. Compared to traditional remediation methods, the Adaptable Reinforcement Method with Radial Cement - Soil Piles offers the following advantages: ① It is capable of synergistically correcting settlement and convergence; ② The construction process is controllable, avoiding damage to the tunnel structure; ③ It possesses long - term stability (post - construction settlement rate < 0.014 mm/d).The findings of this research provide an innovative technical solution for treating diseases in operational shield tunnels and hold significant reference value for similar engineering projects.
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Study on Vibration Source Strength of Large-diameter Metro Shield Tunnels Based on Environmental Vibration

LIANG Jinxue, ZHANG Liangtao, WU Meiquan, WANG Zhengang, XIE Weiping, WEI Panjun, ZHONG Likai

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Abstract:

Large-diameter shield tunnels for metro systems exhibit greater mass compared to conventional shield tunnels, and their vibration source strength is generally considered lower. Consequently, they are regarded as a potentially effective measure for mitigating environmental vibrations induced by metro operations. However, large-diameter shield tunnels have limited applications in existing metro lines, resulting in a lack of measured vibration source data. Moreover, their frequency-dependent source characteristics and influencing factors remain unclear, leaving vibration and noise reduction designs utilizing such tunnels inadequately supported. Field measurements were conducted to compare vibration source strengths and spectral characteristics between large-diameter and conventional shield tunnels along the same metro line. A "tunnel-soil" finite element model was established and validated using the measured data. Subsequently, the effects of geological conditions and lining thickness on vibration source strength were investigated. The results indicate that, under identical train operating conditions, the source strength of large-diameter shield tunnels is at least 7 dB lower than that of conventional shield tunnels, confirming their efficacy in reducing metro-induced environmental vibrations. The vibration source amplitude of large-diameter shield tunnels is lower than that of conventional tunnels within the low-frequency range (1–125 Hz) but higher at frequencies above 125 Hz. Stiffer surrounding soils lead to increased vibration source strength and predominant frequencies. Additionally, a 10 cm increase in tunnel lining thickness reduces vibration source strength by approximately 1.5 dB, and for every 1 m increase in tunnel diameter, the vibration source strength decreases by about 1.9 dB. These findings provide a theoretical basis for evaluating metro environmental vibrations and designing vibration and noise mitigation measures.
1
Research on the treatment technology of hanging disease of existing linear elastic shorter sleepers under time and space constraints

Zhang Yujie, 张慧君, Wang Shuwei, 龚正龙, 高龙

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With the increase of operating mileage and time, existing elastic short sleeper tracks gradually experience problems such as aging and deformation of rubber boots, hanging sleepers, and gauge changes, which affect the stability of the track structure and operational safety. In view of the low construction efficiency of existing disease control methods and the difficulty in meeting the rapid repair of large-area elastic short sleeper diseases, this paper proposes a new empty hanging disease control technology that can meet the minimum gap filling of less than 1mm. The feasibility of the new repair material and construction process was verified through offline pouring tests, and the performance of the repaired elastic short sleeper track was evaluated with the help of static stiffness tests and fatigue performance tests. The results show that this control method can effectively fill the empty hanging area and enhance the overall stability of the track structure. It is suitable for the rapid and efficient repair of existing tracks under time and space constraints, and has important engineering application value.
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Application and Practice of Intelligent Switching Station Based on Cloud Platform Architecture

xiao xiong, 贾琨, He Jing, song xuyang

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【Objective】To address the limitations of the monolithic architecture in traditional smart station construction and to propel the transformation of rail transit towards networked and intensive operations, this study aims to propose and validate a cloud-based deployment paradigm for smart switch stations, founded on a line-level cloud platform. 【Methods】Guided by the Development Outline for Smart Urban Rail Transit in China, a layered and decoupled construction framework for smart switch stations was established. Taking Changsha Metro Line 6 as an empirical case, this framework leverages a line-level urban rail cloud platform to achieve cross-station business collaboration and data model sharing, thereby creating an integrated data link across all stations on the line. 【Results】 Practical application demonstrates that this paradigm significantly enhances hardware resource utilization, effectively reduces operational costs and manpower investment, and optimizes the business process for station switching. Specifically, the process time was shortened by approximately 80%, and the labor requirement was reduced by 3 to 4 personnel per switch operation. This provides a replicable and scalable cloud migration pathway for the digital transformation of rail transit. 【Conclusion】This research is the first to systematically propose a model that utilizes a line-level urban rail cloud platform as the foundational infrastructure to host and support the core capabilities of smart switch stations, thereby achieving an integrated closed-loop from “Platform Construction” to “Application Implementation.”
1
Research on Intelligent Inspection of Evacuation Platform Based on Multi technology Fusion

Wang Ru, Cai Duanyang, Zhuge Huafeng, Wu Cong

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Bolts on rail transit evacuation platforms are often concealed, making comprehensive manual inspection difficult and increasing the risk of loosening or detachment that could compromise operational safety. This paper proposes an intelligent inspection system integrating machine vision and laser scanning to achieve precise detection of bolt defects and clearance intrusion trends. The system employs a dual-track autonomous robot equipped with a high-definition camera and LiDAR, enabling full-coverage inspection through image recognition and point cloud processing. Methodologically, high-resolution image acquisition combined with Adaptive Contrast Enhancement (ACE) is first used to improve image quality. An optimized YOLOv11 and Mask R-CNN are then applied for small-object detection and segmentation, enabling automatic identification of missing bolts, loose nuts, and insufficient protrusion, achieving an accuracy of 94.4%. Furthermore, modeling of laser point clouds and a vector cross-product algorithm are employed to provide clearance intrusion warnings with 2 cm precision. Field tests conducted on the Hangzhou–Haining Intercity Railway, across both elevated and tunnel sections, demonstrate an F1 score of 92.6% for bolt defect recognition and a 0% false alarm rate for clearance detection. The proposed system significantly enhances inspection efficiency and provides technical support for intelligent maintenance of rail transit infrastructure.
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Study on the Impact of Riding-Span Viaduct Construction on Existing Metro Tunnels

LI Chuan, LI Ningning, YAN Jin, WANG Tongtong, ZHU Kerui

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Abstract:

Abstract: o investigate the dynamic impact of riding-span viaduct construction on existing metro tunnels, this study takes the Wangsheren Station to Wangsheren North Station section of Jinan Metro Line 6 as the engineering background. Field tests and numerical simulations were conducted to systematically analyze the deformation patterns of tunnels under the multi-stage coupled effects of "pile foundation excavation, foundation pit unloading, and bridge superstructure loading." The findings reveal that: (1) Foundation pit excavation induces significant tunnel uplift (maximum 4.62 mm), accompanied by horizontal contraction (maximum 1.74 mm) and vertical expansion (maximum 3.25 mm). After bridge loading, the tunnel subsides, with horizontal expansion and vertical convergence observed. (2) The clearance between the tunnel and foundation pit significantly influences uplift deformation: as the clearance increases from 6.7 m to 20 m, the uplift decreases from 5.74 mm to 0.90 mm (approaching zero at ≥15 m), while subsidence remains stable at approximately 5.2 mm. A clearance of ≥12 m is recommended for risk mitigation. (3) Stratigraphic characteristics dominate deformation responses: silty clay layers exhibit greater uplift during excavation (+1.2 mm), whereas gravelly sand layers experience more pronounced subsidence during bridge operation (-1.5 mm). Deformations in moderately and slightly weathered rock strata are negligible. (4) Interval construction of multiple bearing platforms reduces subsequent excavation-induced uplift (12% reduction for the second platform), supporting a "skip-one-excavate-one" construction strategy. Innovatively, this study proposes a deformation prediction model based on stratigraphic heterogeneity, which overcomes the limitations of traditional homogeneous assumptions and provides a theoretical foundation for optimizing the design and risk assessment of riding-span viaduct projects.
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Study on Passenger Path Selection Behavior of Urban Rail Transit Interchange Based on Guidance Information

Wang Chao, Wang Yuchen, Li Xiaoya, Zhang Yuanya

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Aiming at the current situation that the complexity of passenger flow organization and the decision-making mechanism of passengers' path selection behavior during the peak period of urban rail transit stations are still unclear, this paper obtains data through RP (revealed preference) and SP (stated preference) surveys, constructs a model of factors influencing the degree of trust of passengers on the guidance information by using the ordered Logit regression model, and analyzes key influencing factors of passengers' path selection behavior based on the mixed Logit regression model. It is found that passengers' gender, age, and preference of induced information have a significant effect on their trust; the recommendation strength of induced information and the crowd effect of group choice behavior have a positive effect on passengers' path decision-making. This study provides a new perspective for understanding the information processing mechanism and behavioral decision-making mode of passengers in complex traffic environment, and the related conclusions can provide a theoretical basis for optimizing the efficiency of passenger flow organization in rail transit transfer stations.
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Discussion on the Design Parameters of Groundwater Diversion at Metro Stations in Karst Areas

huang yong liang, li hu, hu tao, liu feng zhou, men yan qing, dong ya nan, gao yang, -

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Abstract:

To address the problem of imperfect design theories for reducing groundwater level backwater caused by metro station construction through diversion measures, this study comprehensively utilized methods including theoretical analysis and physical model tests to investigate groundwater flow rate calculation in karst areas, determination of diversion design parameters, and backwater relationships with hydraulic gradient and diversion area ratio. Specific engineering case studies were incorporated, and numerical simulation was used to verify the effectiveness of the diversion design scheme. Results show that: after metro station construction, the groundwater flow path lengthens due to station obstruction, causing backwater; after implementing diversion measures, the flow path shortens and backwater dissipates; water level backwater exhibits a linear correlation with hydraulic gradient, increasing correspondingly with higher hydraulic gradients; under constant permeability coefficient and hydraulic gradient conditions, water level backwater decreases exponentially with the proportion of diversion channel area, with a critical threshold occurring at approximately 20% proportion, leading to the recommendation that the optimization coefficient for diversion design parameters should be no less than 0.2; both gravel replacement diversion schemes and culvert diversion schemes can essentially restore backwater heads to their original state. Numerical simulation results verify the correctness of diversion design parameter values, confirming that the parameter determination method is feasible and meets the requirements for reducing groundwater level backwater.
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Research on High-Precision Measurement Method for Shield Segment Dislocation Movement Based on Laser Scanning

Ju Liyan, Pang Gaozhao, Liu Hongbo, Liu Xuezeng, Liu Xingen

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Targeting the problems of low efficiency, poor coverage, and insufficient accuracy in shield tunnel segment misalignment measurement, an automatic measurement algorithm integrating laser point cloud grayscale conversion with deep learning is proposed. This method can accurately measure segment misalignment, effectively reduce the risk of water leakage caused by misalignment, and ensure the service performance of tunnel structures. Targeting the structural characteristics of shield tunnel segments, an automatic measurement algorithm for segment misalignment is proposed, integrating laser point cloud grayscale conversion with deep learning. First, the collected three-dimensional laser point cloud is converted into grayscale images with enhanced edge features. Then, the lightweight EfficientNet network is utilized to efficiently identify the bounding boxes of inter-ring and intra-ring joints of segments. The bounding box coordinates are mapped to the three-dimensional point cloud space to achieve precise segmentation and extraction of point clouds on both sides of segment joints. Finally, the average radial distances from point clouds on both sides of joints to the center of the fitted ellipse of the tunnel segment structure are calculated respectively, with their difference representing the segment misalignment, enabling non-contact, high-precision measurement of shield tunnel segment misalignment. A tunnel structure inspection vehicle equipped with a three-dimensional laser scanner was developed, integrating the above algorithm and developing supporting data acquisition and processing software. Engineering pilot application was conducted in the shield tunnel section of Hangzhou Metro Line 1, with laser scanning at a mobile speed of 20km/h. Comparative analysis between the inspection vehicle measurement results and manual measurement results shows that the two measurement results are close, with an absolute maximum deviation of 1.6mm. This method can ensure high measurement accuracy even under high-speed mobile conditions, meeting the industry demand for rapid, comprehensive detection of shield tunnel segment misalignment.
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Energy Saving Optimization Method for Urban Rail Flexible Traction Power Supply System Based on Load Clustering

GAO Ming, ZHANG Gang, WEI Wei, WANG Renyu, TAO Boan, XIONG Wei

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Abstract:

The development of flexible traction power supply system presents a significant opportunity for optimizing energy efficiency in urban rail transit. However, the operational conditions are inherently dynamic, characterized by substantial load fluctuations. Consequently, traditional energy-saving approaches, which rely on static scenario designs, struggle to accommodate dynamic load demands effectively. It is necessary to accurately divide load scenarios, study energy-saving optimization methods for flexible systems, achieve dynamic matching of "scenario strategy", and improve energy-saving effects. Hence, an energy-saving optimization approach for urban rail flexible traction power supply systems based on in load clustering is proposed. Firstly, a k-Medoids load clustering method based on t-SNE was designed. A strategy of clustering after dimensionality reduction was adopted to more accurately reveal the inherent laws of urban rail load. Secondly, an energy-saving optimization model for the flexible traction power supply system was constructed. Based on intelligent optimization algorithms, the virtual resistance of traction substation was adjusted to minimize the total incoming energy of the system, achieving energy-saving optimization. Through simulation validation, the effectiveness of proposed method was verified. The designed load clustering method effectively excavated the inherent characteristics of urban rail load, revealed the correlation between system load and operating periods and seasons. 6 specific scenarios of system operation are clarified after load clustering. The proposed energy-saving optimization method can achieve good energy-saving effects in various operating scenarios, with a maximum energy-saving rate of 4.07%. The energy-saving optimization method for urban rail flexible traction power supply system based on load clustering has connected the complete chain of "scene recognition - strategy matching - dynamic adjustment", which can provide important technical support for energy-saving operation of urban rail transit.
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Comparative study on environmental vbration evaluation standards for urban rail transit

LUO Wei

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In response to ambiguities and inconsistencies in China's evaluation standards for vehicle-induced environmental vibrations in urban rail transit, which affect assessment conclusions, this paper adopts a combination of field measurements and statistical analysis to conduct a comparative study of current standards regarding evaluation indicators, weighting curves, analysis frequency ranges, and determination of train pass-by intervals. The main conclusions are as follows: it is advisable to set up both time-frequency synthetical evaluation indicator and frequency-domain octave evaluation indicator. It is suggested to set the single-value evaluation indicator as the maximum vertical vibration level (VLzmax), the frequency-domain octave evaluation indicator as the maximum vibration level of 1/3 octave bands (VALmax), and adopt the peak value retention method in the calculateion. The Wk weighting curve is suggested to be adopted and the analysis frequency range is recommended as 1~80 Hz. In order to effectively eliminate the effect of judgement of train passing period on the evaluation result, it is recommended to use time weighting for vibration signal analysis and peak value retention method for the calculation of VLzmax and VALmax.
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Spatiotemporal Heterogeneity of Land Value Premium Around Urban Rail Transit Stations in Metropolitan Areas: A Perspective of Economic Cycles

Ma Yuansong, Li Junfang, Hu Hua, Jin Hao

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To address the limitations of existing research on land value premiums of urban rail transit, which are characterized by short time spans and insufficient exploration of the long-term dynamic impacts of economic cycles, this study, based on data from the Tokyo Metropolitan Area spanning 1984-2023, for the first time constructs a long-time-series framework covering the bubble period, recession period, and recovery period. It employs the Geographical and Temporal Weighted Regression (GTWR) model to quantitatively capture the spatiotemporal heterogeneous patterns of land value premiums. The results indicate that: 1) During the bubble period, the rail transit-induced land value premium exhibits a core-periphery gradient attenuation, with commercial land demonstrating the highest sensitivity; 2) During the recession period, the premium effect reverses direction, leading to strip-shaped depreciation along rail transit corridors in urban areas , while suburban land maintains stronger stability in its premium levels; 3) During the recovery period, the overall premium elasticity weakens, yet suburban commercial land shows prominent growth potential, with elasticity approximately 1.5 times that of urban areas. The study reveals that there exists a dynamic interaction between macroeconomics and transit accessibility, necessitating the establishment of a cross-cycle response mechanism. This research uncovers the nonlinear dynamic interaction mechanism between macroeconomic cycles and rail transit accessibility, fills the research gap in the quantitative study of cross-cycle spatiotemporal heterogeneity of rail transit-induced land value premiums, provides data support for quantifying such premiums in metropolitan areas under economic fluctuations, and offers theoretical backing for avoiding systemic risks and enhancing planning resilience.
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The Spatially Heterogeneous Influence of Multiple Factors on Housing Prices Around Subway Stations: An MGWR-Based Empirical Analysis in Chaoyang District, Beijing

yutianfu

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Based on a case study of Beijing’s Chaoyang District, this research employs a multiscale geographically weighted regression (MGWR) model to systematically examine the spatial heterogeneity and multi-factor mechanisms affecting residential prices around urban rail transit hubs. Using second-hand housing listing prices from Lianjia in 2023, the study incorporates both internal estate characteristics (e.g., average housing age, property fees, greening rate, and plot ratio) and external location-based attributes (e.g., proximity to subway stations, bus stops, commercial centers, schools, hospitals, and parks) to construct the MGWR model, which is compared against OLS and GWR models. The results show that the MGWR model achieves the highest goodness-of-fit (R2 = 0.691) and effectively captures the scale-varying effects of different factors. Distance to subway stations exhibits a significant negative correlation with housing prices, with a stronger effect in suburban areas than in the urban core. Proximity to top-tier schools shows a heterogeneous pattern—positive in clustered areas but negative in peripheral zones—reflecting a localized saturation effect of educational resources. The influences of commercial, park, and hospital accessibility also demonstrate notable spatial variations, highlighting the complex interplay and contextual dominance of transportation, education, commerce, ecology, and medical services in the capitalization of housing prices. This study provides a multiscale analytical framework for understanding the formation mechanisms of housing prices in the context of urban rail transit, offering valuable insights for spatial governance and public service allocation.
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Analysis of the Influence of Groundwater Level Rise on Subway Station Structure in Cobble Formation

Liang Zhongdong, Li Zhibin, Guan Qifeng, Zhang Yue, Shan Yepeng, Cai Guoqing

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To evaluate and mitigate risks to a subway station founded in pebble strata under rising groundwater, this study—grounded in the DawaYao Station project of Beijing Subway Line 14—utilizes the finite element method to develop a two?dimensional numerical model of a representative cross?section. The model rigorously incorporates strength degradation induced by soil wetting and comprehensively examines the structural internal forces, displacements, and evolution of plastic zones within the ground in response to scenarios of groundwater level rise in gravelly deposits. Meanwhile, the strength attenuation effect of soil after wetting was reasonably considered. The simulation results show that: the base plate, roof plate and sidewalls wall as the enclosure structure, the compressive stress on the soil-facing surface increases, the base plate and roof plate bear the horizontal stress from sidewalls wall and offset part of the spanwise bending moment, the tensile stress decreases; the center plate and the center column as the intermediate support structure still play a good support function; Notably, attention is warranted at stress-concentration junctures like the plate-column and plate-wall connections to avert structural fissures from excessive strain. In a cobble formation, both the stratum and station experience uplift, with the station's uplift marginally surpassing the surrounding soil. Structural integrity remains unscathed without local deformation, thus indicating a relatively diminished risk of localized structural harm. Plastic deformation concentrates mainly within the roof plate's apex, yet without extending into surface ruptures, thereby diminishing the likelihood of comprehensive instability.
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Development And Application of an Intelligent Subway Protection Area Inspection System Based on Video Surveillance

Bai Wenfeng

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To address the shortcomings of real-time and accuracy in existing subway protection area supervision model, an intelligent inspection system was developed that integrates video surveillance with image recognition and edge computing technologies. Firstly, an edge computing system for protection area inspection was constructed using edge computing terminals and monitoring cameras, effectively reducing reliance on cloud servers. Secondly, the YOLOv8l algorithm was selected as the image recognition model for the intelligent inspection system and deployed on edge computing terminals. Finally, a B/S model-based inspection cloud platform was developed for managing inspection equipment, emergencies, and operations. Through training and testing with approximately 100,000 images of 6 categories of mechanical risk sources under various scenarios, the model achieves consistent recognition rates exceeding 90% in both daytime and nighttime conditions. Field tests conducted along Guangzhou Metro Line 5 demonstrate an overall system recognition rate of 85.42%, indicating substantial potential of this video-based intelligent inspection system. This advancement holds significant practical implications for ensuring the sustainable development of urban rail transit systems.
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A Review of Operational Organization in Subway Logistics Systems: Evolution from Single-Line Optimization to Network Coordination

ZHU Yuting, WEI Chang, LIU Lu, GUANG Zhirui, ZHU Mengchen

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This paper zeroes in on the operational organization issues of metro logistics systems, drawing on domestic and international practices and taking literature from 2016-2025 in databases like Web of Science and CNKI as samples. By integrating bibliometric and content analysis methods, it dissects research progress in this field. Subsequently, it delves into literature employing quantitative analysis from perspectives such as research objects, stakeholders, transportation organization modes, train scheduling, capacity allocation, freight flow distribution, model structures, and solution algorithms. The findings show that foreign research had an early start but failed to achieve sustained promotion, while domestic research, despite high attention, remains in a small-scale exploratory phase. Current research lacks systematic connections when analyzing key elements like transportation organization modes, train scheduling, capacity allocation, and freight flow distribution, highlighting the urgent need to construct an integrated optimization framework for multi-element collaboration. The research objects need to be further extended from single-line scenarios to complex networks to enhance the practicality and applicability of the theories. Under the green and low-carbon objective, incorporating energy consumption factors into scheduling optimization, especially introducing strategies like regenerative braking energy utilization, is of great significance. Meanwhile, breaking free from fixed demand assumptions and strengthening response capabilities to uncertainty and elastic demand can improve the alignment between research and reality. Additionally, developing optimization algorithms suitable for large-scale networks remains a key future direction.
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Research on the Optimal Configuration of Urban Rail Transit Photovoltaic-Energy Storage Integrated Equipment Considering Peak-Valley Electricity Prices

Shi Dan

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Under the guidance of the "Dual Carbon" strategy and integrated transportation-energy development plans, the integration of renewable energy sources like photovoltaics (PV) into urban rail transit systems has become a current research focus. However, the inherent uncertainty of photovoltaics energy generation necessitates coordinated operation with energy storage systems, which increases the utilization costs of photovoltaics energy in urban rail transit. Achieving lifecycle profit maximization for PV-storage integration in urban rail systems remains a challenging issue. By analyzing the relationships among energy storage capacity, photovoltaic accommodation rate, investment payback period, and annual revenue curves, this study proposes an optimal configuration scheme for urban rail PV-storage integrated equipment. The scheme fully considers real-world peak-valley electricity pricing factors, reasonably selects energy storage capacity, designs energy storage charging/discharging strategies, and enhances the economic viability of PV-storage integration in urban rail transit. While maintaining photovoltaic accommodation rates, the solution achieves minimized static investment payback periods and ensures lifecycle profitability. This provides a reference for urban rail transit PV-storage integration projects.
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Challenges and Reconstruction of Social Equity in Digitalized Multi-Modal Rail Transit

HOU Binbin, XIA Haishan

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With the advancement of urban agglomeration and metropolitan area development, multi-modal rail transit networks have been expanding rapidly. Technological progress in the digital era has accelerated the integration of artificial intelligence, big data, and transportation systems, facilitating the evolution of multi-modal rail transit toward faster, more efficient, and more user-centered integrated mobility services. However, disparities in benefits persist across different urban spaces and social groups within these smart mobility-based systems. The increasingly complex spatial configurations, mobility services, and modal options, while enhancing accessibility and development opportunities in certain regions and populations, simultaneously pose new challenges to marginalized areas and vulnerable populations. To promote equity within multi-modal transit systems and broaden the spatial and social reach of rail networks, this paper explores the intersection of multi-modal rail transit and social equity. It analyzes key research approaches, critical challenges, and influencing factors, while also proposing future research directions and strategic interventions for enhancing equity in multi-modal transit systems. Findings suggest that two fundamental issues underpin the inequity of multi-modal rail systems, spatial disparities in network coverage and insufficient attention to the diverse needs of users. Rail station and line density tend to be lower in low-density urban neighborhoods and peri-urban or rural areas, making access more difficult. Vulnerable groups, including women, the elderly, persons with disabilities, low-income populations, and individuals with lower educational attainment, are particularly affected by economic constraints, digital exclusion, and time-space coordination challenges in their daily mobility. Future research on social equity in multi-modal transit systems should adopt a holistic perspective that integrates built environment characteristics, transport infrastructure provision, temporal factors, individual attributes, economic policies, intermodal connectivity, and digital literacy. Advancing equity in this context requires innovation in methodological frameworks, identification and quantification of influencing mechanisms. As a capital-intensive foundational infrastructure, urban rail transit plays a critical role in shaping inclusive and equitable transport systems. Addressing social equity in multi-modal transit is vital for enhancing population mobility, increasing employment opportunities, and promoting balanced and sustainable regional development.
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Application Study for Optimization Model and Algorithm of Horizontal Dual lines in Metro Shield Tunnel Section

zhangtianyang, huxiaomin, Yang Dongying, zhouyang

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The horizontal alignment design of urban metro shield section is prone to being constrained by dense structures and land use. It usually results in increased investment and demolition. An optimization model of dual horizontal alignments in metro shield tunnel section is proposed, which takes the intersection points on left line and right line as independent variables. The specification terms are transferred as geometric constraints, and penalty terms of land use underpassing and line space violations are introduced in the objective function. It is solved by a collaborative differential evolution algorithm with left line population and right line population. The case study shows that the proposed model can optimize a horizontal alignment 2.7 km in around 150 seconds, reducing investment 0.3% approximately. It guides the parallel or separated designs of horizontal dual lines in shield tunnel section automatically while avoiding control areas.
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Study on Resilience Evaluation and Application of Longitudinal Structure of Shield Tunnels Considering Severe Disturbances

PANG Yuling, QIN Pengfei, GUAN Zongfu, ZHAN Jinwu

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In light of the rapid expansion of underground rail transit systems and the growing requirements for tunnel operation and maintenance, the longitudinal structural resilience of shield tunnels has emerged as a critical research topic in the field of engineering. In this paper, the longitudinal differential settlement is employed as performance indices, and the ratio of residual performance and normal performance of differential settlements is defined as the resilience metric Re, thus a new model using longitudinal relative differential settlement as the index of tunnel structural resilience performance is proposed. Based on a newly constructed shield tunnel underpasses an existing metro tunnel, the variations of tunnel deformation concerning tunneling distance and construction schedules are analyzed. Then, the degradation characteristics of structural performance during both disturbance stage and recovery stage are effectively captured. Finally, the proposed model is applied to evaluate the structural resilience of existing metro tunnels. The results show that 32.3 % of the performance loss is attributed to the new tunnel undercrossing in the first 38 days. After the completion of the grouting reinforcement, the tunnel performance is improved from 0.677 to 0.868, accounting for approximately 59.1% of the performance loss during the crossing period. Eventually, the resilience metric Re is calculated as 0.764, indicating a high level of resilience for the existing metro tunnel in this case. Moreover, other performance indices related to tunnel longitudinal settlement are compared to validate the rationality and applicability of the proposed performance index.
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A Review of Network Security for Urban Rail Transit

kangyanmei

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With the deep integration of smart urban rail and smart city networks, the high degree of system interconnectivity and open protocols have led to a blurring of security boundaries. Coupled with the emergence of new threats such as APT attacks and supply chain vulnerabilities, urban rail transit network security faces enormous challenges, significantly increasing major risks such as signal system paralysis. To address this critical situation, this article first analyzes the key architecture of the smart urban rail network security protection system from three core dimensions: legal and policy foundations, new technological systems, and ecological coordination mechanisms. It also emphasizes the urgent need to build a "technology + management + ecology" trinity protection system to address the risks of paralysis caused by blurred security boundaries and the combination of APT attacks and supply chain vulnerabilities. In terms of the implementation path of the core protection framework, the key roles of isolation protection and cloud-native architecture are clarified. At the same time, considering the strict requirements of smart urban rail for high real-time performance and high reliability, existing protection technologies are systematically reviewed. Looking ahead to the future evolution of the protection system, it will move towards the mainstream of threat prediction and automated response driven by the deep integration of artificial intelligence, and the practical application of quantum communication to enhance anti-cracking capabilities. It will also be necessary to strengthen joint prevention and control through the construction of cross-industry security alliances and talent training, and ultimately promote the continuous evolution of the entire protection system towards a more proactive, service-oriented and ecosystem-supported form.
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Research on the Online Marshalling Technology Method of Urban Rail Train Control System Based on Vehicle-to-Vehicle Communication

weibaiquan, Shi Hai-feng, Jiang Lu, wangmeng, zhanghao, xujianjun, wangke

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The urban rail train control system based on vehicle-to-vehicle (V2V) communication is being increasingly applied in urban rail transit, thanks to its characteristics of minimal wayside equipment and direct vehicle-to-vehicle communication. To enhance the train transportation efficiency under this system and meet the operational needs of dynamic marshalling adjustment, an online marshalling technology for urban rail train control systems based on V2V communication is proposed, including flexible marshalling technology and virtual marshalling technology for V2V communication. Firstly, the technical scheme and operation procedures for the flexible marshalling function of V2V communication are established, and the core technologies under flexible marshalling are expounded, such as the setting of marshalling area parking points, determination of the vehicle-mounted control end, verification and protection of marshalling forms, collision envelope schemes, and vehicle-vehicle-mounted integration technology. Secondly, the technical scheme and operation procedures for the virtual marshalling function of V2V communication are established, and the core technologies under virtual marshalling are expounded, such as high-performance V2V communication technology, V2V communication security protection technology, collaborative control technology, multi-sensor fusion technology, etc. This study aims to provide a theoretical basis and reference for the marshalling technology operations of the next-generation train control system.
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Progress in the Study of Evacuation Issues in Subway Station Underground Spaces

hong xiaochun, 孙萍, 董杰

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With the expansion of subway networks and the large-scale development of underground space in hub stations, the evacuation of subway stations in underground space in emergencies has attracted increasing attention. In view of the difficulties in emergency evacuation caused by the increasing complexity of subway stations in underground space, based on an extensive review of domestic and international literature, this paper first analyzes the evacuation characteristics and common features of different types of subway station underground spaces, examining evacuation scenarios, pedestrian behavior, and evacuation analysis methods in disaster contexts, and summarizes the evacuation behavior traits across station types. Secondly, the study delves into recent advancements in evacuation experiments and simulation technologies, covering physical and simulated experiments, including core algorithms, simulation processes, and inherent limitations of mainstream simulation platforms. It also highlights the impact of spatial features on simulation experiments and identifies current research hotspots. Finally, focusing on layout and path optimization for evacuation, the paper explores related methodologies and practical applications. On this basis, it points out that existing research is predominantly centered on theoretical modeling and quantitative analysis, with a lack of field validation that limits practical effectiveness. There is also a deficiency in interdisciplinary integration, especially concerning psychological and social dynamics of crowd behavior, which constrains the effectiveness of evacuation strategies in emergency practice. Therefore, the study suggests enhancing model realism through virtual reality, big data, and artificial intelligence technologies to improve simulation accuracy; and encourages interdisciplinary collaboration among psychology, sociology, urban planning, and safety engineering to comprehensively analyze crowd evacuation behaviors in different types of subway station underground spaces during emergencies, thereby providing a solid theoretical foundation and practical reference for future research.
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Evaluation of coordinated development of Beijing rail transit stations and cities from the perspective of node place coupling

tanpengjing, zhangyanan, xiyang, lijiang

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Beijing"s rail transit network has reached an operational length of 836 km, forming a comprehensive system with multiple key hub nodes, and its construction is still ongoing. Rail transit plays a crucial role in supporting and driving urban development. The coordinated development of stations and surrounding land can foster a positive interaction between transportation and the city, alleviating traffic congestion while maximizing the use of transportation resources. This paper takes Beijing as a case study, establishing a Node-Place model, and utilizes multi-source big data methods to comprehensively assess the development of station nodes and places in Beijing by the end of 2023. A comparative analysis with the situation in 2019 is conducted to summarize the characteristics and trends of coordinated development, classifying stations into five categories, including stable balance and fluctuating balance. The results show that the city"s stations exhibit a balanced development between node and place values overall, with node value slightly exceeding place value. At the citywide level, station-area integration should be strengthened. In contrast, 29 stations located on suburban lines show a trend of continuous deterioration in place value, which is closely related to the lagging development of surrounding land. Guidance and promotion of land development around these stations should be intensified. The findings contribute to forming an improvement project database that addresses the development issues of different stations and provides support for achieving station-city integration.
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Study on Deformation Mechanism and Safety Early Warning of Wet Trapped Loess Tunnel

HUANGXin, Yuyongtang

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To investigate the structural damage characteristics and deformation mechanisms of operational metro tunnels in collapsible loess regions, this study conducted long-term structural deformation monitoring on a metro tunnel in Xi’an, China. Safety assessments of tunnel sections were performed based on monitoring data, with numerical simulations further revealing the deformation causes in high-risk zones. The monitoring data show that the study line tunnels present a composite deformation pattern of arch subsidence and structural expansion dominated by arch subsidence, of which the Z5~Z6 intervals have been evaluated as high-risk sections due to the seriousness of the disease. Numerical simulations demonstrate distinct deformation mechanisms: saturation of soil above the tunnel crown predominantly induces horizontal ovalization deformation ("horizontal egg-shaped" distortion), while saturation below the invert mainly triggers overall subsidence with minimal impact on structural dilation or surrounding rock pressure. Combining the geological investigation and deformation monitoring data, the structural expansion and deformation monitoring values match well with the predicted values of 4~8m flooding depth in simulation condition 3 (groundwater level rise), confirming that the compressive deformation triggered by the flooding of old loess under the arch is the main cause of structural deformation in this section. The findings provide valuable insights for the construction and operational maintenance of urban rail transit systems in similar collapsible loess regions.
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Suggested Performance Indicators for Urban Rail Transit Operations ——A Case Study of Shanghai Metro

Luhongai

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The index system dominated by KPI key performance indicators has problems such as honeycomb fragmentation between departments, alienation of incentive functions, and insufficient process supervision. In the face of the era opportunities of smart urban rail construction and high-quality development, it is necessary to explore and design a new performance index system that can better help enterprises transform their strategic vision into an executable path. The mature OKR target and key result method are proposed as the core idea of optimization design. Guided by the framework system of "department internal control index-up and down vertical alignment index-left and right horizontal coordination index", following the logical chain of "target stratification-task quantification-result closed loop", focusing on the main responsibility and main business, building department internal control index to strengthen process management; matching department division of labor to set up strategic empowerment special indicators to strengthen positive incentives; establish a four-level linkage mechanism of "strategy-process-department-post", and build cross-departmental coordination indicators.Shanghai Metro is selected as the research object, and a new index system is designed and formed, which belongs to the department level and the field level, such as the list of "strategic objectives-key results-empowerment special indicators" and the list of cross-departmental horizontal linkage constraint indicators. Since its trial in December 2024, employees' trust in the evaluation results has been increasing day by day. Organizations at all levels can easily carry out key results process traceability and progress inspection; more efficiently analyze the key "why" behind the problem representation ; more agilely put forward targeted improvement measures.
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Method Research on Fault Tree Analysis (FTA) and Reliability Performance Modeling for Regenerative Braking Energy Feedback Devices

ZHANG Muran, ZHANG Yuyang

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The development of power electronics promotes application of DC regenerative braking energy feedback devices in DC urban rail transit systems, which means another power semiconductor based equipment, other than rectifier, as a critical component of the DC traction power supply system. In order to analyze its reliability performance in operation, this study collected and analyzed fault event data from energy feedback devices in a domestic metro system, preliminarily constructing a fault tree model for such devices, experimentally employing Gaussian kernel density estimation (KDE) to estimate its failure probability distribution functions. The result shows MTBF of the device between 21900 to 47400 hours, enhancing both the intuitiveness and scientific understanding of fault data and their distributions. This approach provides an effective reference for comprehensively evaluating device performance and optimizing maintenance schedules and overhaul strategy.
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Exploration and Research on the Freight Model of Urban Rail Transit

XUAN Jing, CHEN Nan, LI Jirong, ZHANG Zhening, LU Xiaoxiao, CHU Zhongfu, XING Songling

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With the rapid growth of urban logistics demand, traditional road-based freight transportation is facing issues such as low efficiency and significant environmental pressures. Leveraging surplus capacity in urban rail transit to develop urban freight services has become an important direction for innovation. This paper examines typical domestic and international cases, analyzes the existing problems of various urban rail freight models, and proposes systematic solutions. Based on these, it outlines design ideas for optimizing transport organization schemes. The results show that, in response to four core issues, such as the imbalance of spatial and temporal resources, optimization can be achieved through peak–off-peak time windows, flexible facility retrofitting, demand-responsive organization, and end-to-end safety management. Relying on three types of models, the approach advocates starting with pilot projects on specific lines, and, after technical verification and readiness, gradually expanding to broader applications. This study provides theoretical support and technical guidance for the implementation of urban rail freight models, promoting the development of an efficient and green urban logistics system.
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Research and Application of Key Technologies for Flood Control Safety Assessment of Nanjing Rail Transit Operation Lines

Wang Yan, Xu Min, Ma Qiuju, Hou Pan, Chen Qingqing, 程泽农, Zhu Lili, Wang Jie

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In recent years, extreme weather has frequently occurred in various parts of China, and the intensity of local rainstorm has significantly increased. As an important mode of transportation, the rail transit system will cause serious losses once it encounters rainstorm and flood disasters. Focusing on the issue of flood prevention safety assessment during the operation period of rail transit lines, this study takes the Nanjing rail transit lines as an example, a key technical system for flood prevention and safety assessment during the operation period of Nanjing rail transit lines was constructed for five types of locations (subway stations, vehicle bases, substations, section air shafts, and vehicle access tunnel entrances). The system mainly includes dividing flood prevention zones, analyzing disaster causing factors, establishing risk assessment matrices, and proposing flood prevention and control measures. Based on the key technical system for flood safety assessment during the operation period of the constructed rail transit operation line, the study divides the Nanjing rail transit operation line into 33 primary zones and 45 secondary zones; According to the flood risk assessment matrix, there are a total of 14 major risk points, 101 major risk points, 180 general risk points, and 62 minor risk points on the operating lines of Nanjing Rail Transit, with the major risk points mainly concentrated on Line 2, Line 3, and Line 10. The research results will provide theoretical guidance for ensuring flood prevention safety of urban rail transit operation lines.
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Influence Mechanism of Railway Vehicle Status on Tunnel Vibration Source Strength in Suburban Railways

SunKui

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In order to study the influence of vehicle status on the vibration of wheel-rail system in urban railway, a vertical coupling dynamic model of vehicle-track-tunnel is established, and the influence mechanism of driving speed, train passenger capacity and wheelset mass on the vibration response of vehicle, rail and tunnel is analyzed in detail. The research results show that with the train speed increasing from 100km/h to 160km/h, the maximum Z vibration level of the tunnel increases from 68.05dB to 72.06dB. With the increase of train passenger capacity, the vertical ride comfort index of vehicles gradually decreases, while the vertical wheel-rail force, rail vertical displacement, rail vertical acceleration, rail maximum Z vibration level and tunnel vertical displacement gradually increase, while the tunnel vertical acceleration and maximum Z vibration level remain basically unchanged. The train passenger capacity mainly affects the tunnel vibration response in the frequency range below 10Hz. In the frequency range above 10Hz, the tunnel vibration response is mainly controlled by wheel-rail irregularity, resulting in no significant difference in tunnel acceleration levels under no-load, full-load and overload conditions. Below the P2 resonance frequency of wheel-rail system, increasing the wheelset mass will amplify the vibration acceleration level of rail and tunnel. However, above the P2 resonance frequency, the vibration acceleration level will decrease.
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Impact of Rail Transit Integration on Accessibility to Tertiary Hospitals and Its Spatial Equity in the Chengdu Metropolitan Area

PENG Yisheng, LIU Jiahui, 陈林, 方翰, YANG Linchuan

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Aiming at the issue that most existing studies neglect the impact of urban agglomeration-level rail transit integration on the accessibility and equity of tertiary hospitals, this study introduces the two-step floating catchment area (2SFCA) method and population-weighted mean absolute deviation to measure accessibility and spatial equity, respectively. By constructing two scenarios of the current situation and rail transit integration, the evolution of the accessibility and spatial equity of tertiary hospitals in the Chengdu Metropolitan Area is systematically analyzed. The findings are as follows: First, rail transit integration promotes the overall improvement of tertiary hospital accessibility. Second, as rail transit integration progresses, the spatial polarization of accessibility gradually weakens, and the areas that cannot obtain high-quality medical services are also decreasing. However, the accessibility difference between the east and west sides of the Longquan Mountain Range is becoming more pronounced. Third, rail transit integration reduces spatial differences in accessibility and promotes spatial equity. Based on these findings, optimization strategies to promote the balanced and high-level coordinated development of tertiary hospitals in the Chengdu Metropolitan Area are proposed.
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Research on Early Termination Schemes of Urban Rail Transit PPP Projects

Zhang Haiying

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In view of the numerous controversies surrounding urban rail transit Public-Private Partnership (PPP) projects, this paper analyzes the main problems during the operation period of such projects. To ensure the stability of urban rail transit operations during the operation period and safeguard the interests of all investors, three feasible solutions are proposed from the government’s perspective, with an analysis of their implementation processes as well as their respective advantages and disadvantages. The research concludes that early termination of franchise rights through equity transfer is the relatively superior approach, as it offers strong operability, does not affect normal operations, helps maintain workforce stability, imposes relatively low fiscal pressure on the government, and aligns with policy requirements. Finally, taking China’s first urban rail transit PPP project that was terminated during the operation phase—the Fuzhou Metro Line 2 electromechanical equipment PPP project—as a typical case, the study provides a detailed account of the entire process of successfully repurchasing the equity held by private investors and terminating the franchise agreement in advance, with the aim of offering reference and guidance for equity repurchase and exit practices in urban rail transit PPP projects. Keywords: PPP projects; urban rail transit; early termination; equity transfer; operation period
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Review of Prediction and Control for Surface Settlement Caused by Shield Tunnelling Based on Machine Learning

Li Chuitian, LIN Xiaoqiong, ZHANG Ji, XU Kaicheng, CHEN Mengcheng

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Predicting and controlling the surface settlement induced by shield tunneling is an important engineering problem in underground space development. With the development of artificial intelligence technology, machine learning algorithms have achieved good application results in surface settlement prediction and control. In this paper, we first summarizes the theory of machine learning, focusing on four key aspects: database construction, data preprocessing, model selection and evaluation, and shield tunneling parameter optimization under settlement control. Additionally, it critically examines the limitations of existing research in this domain. Current research issues include neglecting the additional impacts of surface structure loads, traffic flow, and pedestrian activities, a lack of model interpretability, and the balance between prediction accuracy and practicality. Future research should focus on developing a comprehensive measurement and evaluation system that incorporates the dynamic effects of surface buildings, traffic, and pedestrian flow into settlement prediction models. At the same time, efforts should be made to enhance model interpretability and promote the dynamic updating of machine learning models with real-time monitoring data, providing more scientifically sound guidance for safety control in shield tunneling construction.
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Design and Implementation of Adaptive 3D Scene Roaming Technology for Rail Transit Engineering

ZHANG Huiyi, ZHOU Kan, WANG Bo, LAI Huahui

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In response to the problems of complex interaction, poor path planning, and untimely information display in traditional roaming methods in the three-dimensional scenarios of rail transit engineering, an adaptive roaming method is proposed to solve the pain points of three-dimensional scene visualization and engineering information display and communication. By integrating long-line, large-scale, and multi-source heterogeneous data generated during rail transit informatization, building information model (BIM) and geographic information system (GIS) data fusion technology is used to build high-precision three-dimensional scenarios. Automatically plan to generate the optimal roaming path based on line geometric features and interest point distribution; combined with key technologies such as camera attitude dynamic control, roaming interest point capture, and information synchronization display, smooth transition of perspective and real-time presentation of key information are achieved. The technology is applied to the information construction process of one national railway and five intercity railways in Shenzhen, forming a rail transit BIM+GIS roaming system, providing an efficient and interactive three-dimensional visualization solution for rail transit project management, application display and communication.
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Research on the Connotation, Issues, and Countermeasures of the "Four-Network Integration" of Rail Transit in Metropolitan Areas

WANG Chao, YANG Le, LUO Yining, LIU Chenzhuo

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"Four-Network Integration" of rail transit, which refers to the integration of urban rail transit, suburban railways, intercity railways and trunk railways, has become an important driving force and breakthrough point for advancing railway reform, achieving regional integration, serving the national strategy of building a strong transportation network, and supporting high-quality development in new urbanization. The connotation of "Four-Network Integration" encompasses both multi-level railway classification and multi-level railway integration, which are mutually reinforcing. The underlying requirement of multi-level railway classification is to ensure the coordinated efficiency of the "four networks," where the hierarchical structure should facilitate the balanced development of passenger flow patterns. The focus of multi-level railway integration, based on implementation pathways, can be subdivided into planning and construction integration, operational service integration, and management mechanism integration, ultimately achieving temporal, spatial, and functional integration. Building upon this framework, this paper analyzes two domestic cases: the single-platform-interchange at Chengdu's Xipu Station and the cross-line operation between Chongqing Rail Transit Jiangtiao Line and Metro Line 5. Finally, this paper examines the current challenges faced by China in the process of promoting "Four-Network Integration", including: unreasonable network structure, delayed planning and construction, insufficient coordinated service levels, and imperfect coordinated institutional mechanisms. Based on this analysis, targeted strategic recommendations are proposed to provide theoretical support and practical guidance for the sustained and healthy development of "Four-Network Integration" of rail transit in China.
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Research on Key Construction Technology of Subway Shield Tunneling Through Existing Building Anchor Cables Groups——Taking Shenyang Metro Line 3 as An Example

Tian yudong

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Based on the shield tunneling subway crossing through the existing anchor cable group between Wenfu Road Station and Fuming street station of Shenyang subway line 3 as the background. The paper analyzed various treatment schemes for shield tunneling through anchor cable areas. By comparing and selecting comprehensive factors such as technology, economy, and construction period, and combining with the actual situation of the project, a scheme is proposed for the excavation of tunnels using the Mining primary lining method , which involves removing and treating the intrusion anchor cables , back-filling with mortar, and then shield tunneling is used to pass through.Perform numerical model analysis for various construction stages, and conduct a comparative summary analysis by incorporating on-site monitoring data. Research shows that the Mining methods can effectively remove anchor cables. And the method of back-filled with mortar eliminates obstacles and hidden dangers for shield tunneling construction. The shield tunneling process is normal and does not require opening machine cabin.The surface deformation data from construction monitoring is slightly larger than that from numerical analysis, but the deformation patterns are basically consistent, both showing a trend of larger values in the middle and smaller values towards the edges. Engineering practice has proven that the method is safe and reliable, and it can provide a reference for similar projects.
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Research on the Planning Practice and Strategy of "Four Network Integration" in Rail Transit: A Case Study of Guangzhou City

Shiwei Xu, Junxing Qiu, Shufeng Ye, zhiming Xie, Xue Zhao

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To promote the integration of the "four networks" of rail transit and better support the development of urban agglomerations and metropolitan areas. By deeply analyzing the connotation and characteristics of the "four network integration" of rail transit, the role and significance of the "four network integration" have been summarized; On this basis, a systematic review of the integration planning practice of Guangzhou's rail transit four networks was conducted, and relevant thoughts were proposed from the aspects of top-level design, operational organization, and institutional mechanisms. The research results indicate that in order to promote the integration of the four networks with high quality, firstly, a rail functional hierarchy system suitable for the development of the metropolitan area should be established based on the spatial scale, central system, and passenger flow demand of the metropolitan area. Secondly, for a certain direction of passenger flow corridor, it is necessary to fully consider the characteristics of passenger flow demand, and study the reasonable configuration of different lines within the same channel from the perspective of leveraging the advantages of various levels of track functions. Once again, the appropriate network integration method should be selected from a global perspective, taking into account both demand and cost, and considering the applicability of interconnectivity and hub node transfers. Finally, efforts should be made to promote mutual trust in security checks and interoperability of ticket systems to facilitate citizens' travel.
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Experimental study on void detection behind subway tunnel lining and signal denoising method——Combined denoising method based on Butterworth bandpass filter and Daubechies8 wavelet transform

peilejun, Tang chao

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With the increase of service life of urban rail transit, the stability of subway tunnel lining is getting worse and worse. Aiming at the problem of difficulty in detecting voids behind lining, impact echo method has been developed as a new means to detect such diseases. Among them, effectively extracting echo oscillation characteristics from complex signals of detection data has become the key to detecting voids behind lining. Based on the voids detection experiment behind" segment-surrounding rock" full-scale model, this paper proposes a denoising method based on Butterworth bandpass filter signal coarse screening strategy combined with local noise smoothing based on Daubechies8 wavelet transform. This method uses 4th-order bandpass filter and sets high and low frequency cutoff frequencies of 1 kHz and 50 kHz to effectively suppress signals and noise outside the frequency band; wavelet transform based on improved adaptive threshold method smoothes signal spikes and finely removes residual noise within the frequency band. The results show that after denoising the two-dimensional time-frequency diagram of experimental data by this method, high-frequency spikes are suppressed in the frequency domain, low-frequency discrete noise is removed, and echo signals in the passband are smoothed; the distribution characteristics of echo signals are retained in the time domain to reduce noise interference. The joint denoising method proposed in this paper significantly improves the extraction effect of the echo signal oscillation characteristics, and provides a preliminary research basis for the impact echo method to detect voids behind the lining of subway tunnels.
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Knowledge Organization and Application Research of Metro Construction Quality Acceptance Standards Based on Knowledge Graph

JIZHONGXUAN

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[Objective] To effectively integrate knowledge from metro construction quality acceptance standards and address the current issues of single knowledge organization, as well as isolated and fragmented knowledge. [Methods] Based on the collection of metro construction quality acceptance standards issued by national and representative municipal authorities, generative AI was employed to extract key knowledge elements. A knowledge graph was then constructed using graph database software, and a multidimensional knowledge retrieval method along with node importance evaluation were proposed. [Results] Taking the construction of metro open-cut stations as an example, the proposed methods were applied to conduct an in-depth analysis of key knowledge at various stages of quality acceptance for this unit project, and acceptance recommendations were provided. [Conclusion] The knowledge graph of metro construction quality acceptance standards can offer comprehensive knowledge support for quality acceptance, providing significant reference value for improving the knowledge management level and utilization capability of metro construction quality acceptance standards.
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Optimization Method for Freight Intermodal Transportation of High Speed Rail and Urban Rail Transit Based on Complex Networks

HUANG Baojing, CHEN CHENG, 王嘉源

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To address the need for efficient transportation of high-value-added and time-sensitive goods and resolve the challenge of selecting optimal freight paths within the complex urban rail transit networks of megacities, this study presents a comprehensive approach. First, a network simplification method is proposed to streamline the topological structure of urban rail systems by accounting for network complexity and uneven passenger flow distribution, thereby enhancing the computational efficiency of multimodal path optimization algorithms. Second, a path optimization model is developed with dual objectives of maximizing load rate and minimizing operational costs to balance cargo capacity utilization and economic feasibility. Finally, a hybrid algorithm integrating an improved ant colony optimization and particle swarm optimization is designed to solve the model, where particle swarm optimization optimizes the hyperparameters of the ant colony algorithm to accelerate convergence speed. Validated through a case study in Guangzhou, the methodology achieves significant performance improvements: network simplification reduces nodes by 76% and links by 69%, cutting algorithm runtime from 11,849 seconds to 1,613 seconds and boosting computational efficiency by 87.4%. The hybrid algorithm further reduces iterations from 46 to 15 while maintaining solution quality. Comparative analysis confirms the superiority of this approach in balancing computational speed, resource utilization, and path optimization effectiveness for urban rail freight systems.
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Performance study and economic analysis of a cold storage air-conditioning system using PCMs in a subway station

HAN Yong, LUO Yanping, HUANG Feiyan, CHEN Xiaoming, ZHANG Wenwu, ZHANG Quan

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In order to reduce the operational cost of air-conditioning systems in subway stations, a cold storage air-conditioning system using phase change materials (PCMs) is proposed. The system can operate in four modes, namely, space cooling and cold charging by chillers, space cooling by chillers, space cooling by cold discharging, space cooling by chillers and cold discharging modes. The PCM used is a commercially available inorganic material, and its phase change temperature range is 7.5~8.5 oC and heat of fusion is 140 kJ/kg. The PCM is encapsulated in panel containers. A series of PCM slabs are parallelly arranged in the cold storage tank. The gap between the two adjacent PCM slabs serves as the flow channel for water, which exchanges heat with PCMs to store and release cold energy. The characteristics of chillers and cooling towers are modeled with the curve fitting method using the measured performance data. A dynamic computational model of the cold storage system which consists of a heat transfer numerical model of PCM slabs and the performance curves of chillers and cooling towers is built. The simulations are performed under the measured data in a subway station in Guangzhou. A control strategy is developed, then, the performance of the cold storage system is studied and compared to the conventional air-conditioning system. The variations of the melted fractions of PCMs, the inlet temperature, outlet temperature and water flow rate of cold storage tank, chillers and cooling towers, and the input power of system versus time on May 1st in 2023 are analyzed. Also, a economic analysis of the proposed cold storage system is performed. The results show that, under the demand tariff, 8.27% annual operational cost is saved by the cold storage system over the conventional system, with a static payback period of 6.3 years. While 13.34% can be saved by the cold storage system against the conventional system under the discounted electricity tariff, with a static payback period of 3.7 years.
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Metro Train Rescheduling based on Earthquake Early Warning Information

Shi Kexin

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In response to seismic events that render certain metro sections impassable or subject to speed restrictions, this study proposes an optimization model for metro train emergency rescheduling based on Earthquake Early Warning (EEW) information. The model proactively adjusts existing train operation plans before the earthquake occurs, upon receiving EEW alerts. It incorporates constraints such as arrival and departure time constraints, headway constraints, rolling stock circulation constraints, and earthquake impact-related constraints. The objective function aims to minimize the deviation between actual and ideal train headways, the number of skipped station stops, and the time trains operate within hazardous zones after the earthquake. A linearization method is used to convert the model into a Mixed-Integer Linear Programming (MILP) formulation. To verify the effectiveness of the proposed model under various earthquake scenarios, a case study is conducted using actual operational data from Line 6 of the Kunming Metro on a typical working day. The results show that the model can generate emergency train rescheduling plans based on EEW information under different earthquake intensities and affected areas. Different rescheduling strategies are adopted depending on the location of the train at the time of receiving the EEW alert. When speed restrictions are imposed due to the earthquake, a greater increase in inter-station running time leads to a more significant impact on train operations.
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Key Technologies and Demonstration Applications of the New Generation Regenerative Braking Energy Utilization System

Zhong Zhihong, Zhao Yajie, Lin Fei, Yang Zhongping, Sun Yuejia, Diao Chuanfei

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Aiming at the technical challenges of urban rail transit regenerative braking energy utilization system in capacity configuration, safety design, energy management, energy saving evaluation and other aspects, this paper proposes a new generation of stored regenerative braking energy utilization system eRAM. Innovatively constructed: (1) capacity optimization model and algorithm based on parameter decomposition; (2) Multi level safety architecture considering rail transit application scenarios; (3) An interval energy dynamic allocation algorithm based on key parameter identification; (4) Distributed cooperative control strategy based on deep reinforcement learning; (5) Condition monitoring and life prediction of energy storage components based on data driven. This paper will explain the basic principles and key technologies of each important component, and show and analyze the actual effect of the application demonstration of these technologies in Beijing Metro Batong line, in order to provide a useful reference for the development of regenerative braking energy absorption and utilization technology of urban rail transit.
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Research on the Application of SBAS-InSAR and ARIMA Models in Subway Settlement Monitoring and Prediction - Taking Urumqi Subway as an Example

DENG Wenbin, DENG Liuyang, CAO Shuaizhen

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In order to effectively identify and prevent and control the safety hazards of ground settlement along the subway lines and surrounding areas, it is crucial to carry out systematic settlement monitoring. In this study, the spatial and temporal evolution characteristics of ground settlement in Urumqi metropolitan area, including cumulative settlement and settlement time series data, are obtained based on the small baseline set interferometry (SBAS-InSAR) technique. At the same time, the autoregressive integral sliding average (ARIMA) prediction model is combined to predict the deformation trend of the key subsidence areas, and an in-depth analysis is carried out for the typical subsidence sections along the subway line. The results of the study show that: Shayibak district, Shuimogou district, Urumqi county and the new urban area have obvious subsidence and subsidence funnel areas, and the annual subsidence in some areas reaches -31.4~-7.3mm. the subway line 1 and 2 have obvious subsidence in some sections, and the area of subsidence area is large, which needs to be paid attention to the road section. The ARIMA model is used to predict the future 12-period data of the two settlement areas of D4 and D5 with high prediction accuracy, which can be used as a reference for later monitoring.monitoring.
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Active Rail Potential Hardware Dynamic Emulator System

wangzhenshuai, yangxiaofeng, sunxiangxuan

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To address the difficulty of on-site verification of urban rail transit rail potential and stray current prevention measures, the hardware dynamic emulator system of rail potential has attracted widespread attention. Existing hardware emulator schemes usually generate the dynamic equivalent output resistance by modulating the average input time of a fixed power resistor. However, due to fixed power resistor heating and power limitations, it is difficult to increase the power rating. Therefore, this paper proposes an active rail potential hardware dynamic emulator (ARPHDE). Based on analysis of operating principle of ARPHDE, the coordinated control strategy for the virtual resistance converter unit (VRCU), large resistance converter unit (LRCU) and section switching switches is developed, enabling precise regulation of the equivalent virtual resistance value. Simulation results demonstrate that the ARPHDE can accurately reproduce the spatiotemporal dynamic distribution patterns of rail potential. Compared to traditional passive hardware emulator schemes, the ARPHDE replaces fixed power resistor regulation with virtual resistance regulation, avoiding issues of fixed power resistor heating, showing promising application prospects.
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Practice and Enlightenment of Tokyo Metro Underground Station Platform Renovation

WANG Zhenbo

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China is currently exploring and practicing the technologies of underground station platform non-suspension renovation under non-reserved conditions. In contrast, Tokyo Metro has mature civil engineering renovation technologies and rich platform renovation cases and experience. It is necessary to investigate the civil engineering renovation situation and the platform renovation practice of Tokyo Metro underground stations to derive enlightenments for domestic applications. Firstly, through statistics, the spatiotemporal distribution characteristics of Tokyo Metro stations that have undergone civil engineering renovation are analyzed, and the influence of laying method and reserved conditions on the timing and construction duration of renovation is explored. Subsequently, the process for civil engineering renovation of Tokyo Metro underground stations is delineated. Finally, based on specific cases, the main objectives and key points of platform extension, platform widening, platform addition and comprehensive platform renovation are analyzed and relevant enlightenments are summarized. About 15.1% of Tokyo Metro underground stations have undergone civil engineering renovation. Only platform extension may have reserved platform extension space based on the length of future train formation, whereas platform renovations under non-reserved conditions prioritize minimizing renovation scale and will have long construction duration when adopting non-suspension construction. Underground lines need to pay attention to reservation design with high cost-effectiveness. The civil engineering renovation construction steps of underground stations usually follows "from outside to inside, first building new and then demolishing old". The underground station platform renovation under no reserved conditions needs to emphasize targeting and control the renovation scale. The long-term station renovation project needs to strengthen risk warning and dynamic control. Station-city integration requires balancing station passenger flow carrying capacity with surrounding land development intensity.
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Early-Stage Study on Urban Rail Transit Network Planning Revision

yinyong

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Existing visual‐based fatigue detection methods often suffer from poor scene adaptability and insufficient modeling of temporal feature dependencies. To address these limitations, this paper presents a facial multi‐feature and Bi LSTM–based fatigue detection algorithm for intelligent track guided vehicle drivers. First, Dlib is used to locate facial landmarks and compute five fatigue‐related parameters (EAR, MAR, and three head‐pose angles), and a novel vertical head‐scan frequency metric is introduced for distraction detection. These features are then encoded via a feature‐encoding layer to capture higher order representations and fed into a Bi LSTM network to model temporal dependencies. To further strengthen the representation of critical fatigue cues, a temporal attention mechanism is integrated into the Bi LSTM. Experimental evaluation on a custom mixed dataset demonstrates a detection accuracy of 94.24%, outperforming traditional baseline models. Moreover, in simulated driving trials, the proposed method achieves accurate, real time detection of both fatigue and distraction states under challenging lighting conditions and varying driver postures. These results confirm that the multi‐feature fusion, temporal encoding, and attention‐enhanced Bi LSTM jointly improve robustness and precision in driver state monitoring applications.
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Subway Vibration Response Characteristics of a Large TOD Underground Complex

WANG Chen, JIANG Zhiwei, XIA Ruimeng, WU Chenggang, LOU Haicheng

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With the TOD background of urban rail transit, urban underground complex structure is often joint constructed with a subway tunnel. But the running trains in tunnel can also induce vibration responses of the underground complex, which may have negative effect on the functional use of the structure. In the paper, with the background of Changchun ‘Galaxy One Mile’ large underground complex engineering, the three-dimensional soil-structure nonlinear finite element method was used, as well as the vehicle-track coupling dynamics sub-model. Time history analyses on the vibration of the large underground complex were conducted, under the subway train load. After the modelling method was verified through the in-situ measurement results, the interlayer and transversal vibration responses of the underground complex were acquired. Results show that the train induced vibration could directly transit upward from the bottom of the column and wall, and it degraded via the slab in the horizontal direction. Therefore, the columns that have the smallest horizontal distance to the rail center and the nearby regions, are always the regions that have the strongest vibration responses. But the in region that far away from the train excitation, vibration of slab should be more focused.
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Operation Optimization of Regional Virtual Coupling Train by Integrating the Train Scheduling and Control Considering Passenger Service Levels

WU Xueliang, LIU Junqing, FU Ze, LV Jidong

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As urban rail transit networks continue to expand, junction areas in cross-line operations have increasingly become critical bottlenecks limiting capacity improvement. To alleviate passenger congestion during peak hours, this paper proposes a virtually coupled train coordination and scheduling method that incorporates passenger service level considerations. A train dynamics model is first established based on traction-braking characteristics and state transition rules. Then, a passenger-oriented Nash equilibrium game framework is constructed by introducing passenger priority levels to achieve coordinated optimization of train operation strategies. Furthermore, a bi-objective optimization function is formulated to balance two key indicators: passenger travel time and platform crowding. Simulation results demonstrate that, under peak operating conditions, the proposed method reduces passenger travel time cost by approximately 3% and platform congestion by around 30% compared to the traditional First Come First Serve (FCFS) strategy and the moving block-based game approach, significantly enhancing transportation efficiency and passenger satisfaction in cross-line operation zones.
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Research on Fatigue Stress Monitoring of Suspension Components at the End of Structures Based on Deep Learning Methods

DAI Xiaochao, HU Jie, JING Yuhang

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With the continuous operation of rail transit vehicles, the fatigue failure of end-suspended components on the vehicle frame has become increasingly prominent, posing a potential threat to operational safety. This study addresses the challenge of directly monitoring vibration-induced fatigue damage in these components during long-term service. Taking the track inspection device as an example, its fatigue failure mechanism was analyzed, and a deep learning-based indirect fatigue stress monitoring scheme was proposed. Hazardous measurement points were identified via finite element analysis, and data on vibration acceleration at the frame end and component stress were collected through field line tests. Three temporal regression models (RNN, LSTM, and TCN) were constructed to establish the mapping relationship between acceleration loads at the frame end and component stress. The attention mechanism was introduced to optimize model performance. Experimental results demonstrate that all three models effectively predict stress, with the LSTM model incorporating the attention mechanism (LSTM-Att) achieving the highest prediction accuracy. Validation on six stress measurement points of the track inspection device confirmed that LSTM-Att exhibits excellent predictive performance in both the time and frequency domains. This proves the effectiveness of the proposed method and offers a novel approach for monitoring fatigue damage in frame end-suspended components.
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Research on the driving organization scheme of urban rail transit machinery under flexible marshalling mode

CHEN Yang, XiangHong

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Research Purpose：In order to solve the problem of uneven distribution of passenger flow, realize the accurate matching of transportation capacity and efficient utilization of operating resources, flexible marshalling mode has become a hot spot for the high-quality development of urban rail transit in various places. Taking Qingdao Metro Line 5 as an example, this paper focuses on the content of driving traffic, train allocation, wiring setting, capacity calculation and life cycle economic benefit analysis in the online decompilation and linkage mode, which can provide effective guidance for the practice of subsequent projects. Research Result：(1) The flexible marshalling operation site should be in the wiring area of the intersection switchback station and the entry and exit line connection station, and the switchback station should be arranged according to the double switchback line to improve the operation capacity; (2) The technology is implemented in the project investment, and the main increase in the cost is mainly for vehicles and signal systems (about 90%), and it is recommended to give priority to reserving technical conditions such as wiring and platform doors in the early stage; (3) Compared to the conventional 6-car fixed formation scheme, the use of 6-car fixed formation and 3+3 flexible formation hybrid scheme is more economical and applicable, with significant savings in traction energy consumption and maintenance costs. However, at present, the technology still faces issues such as limited system capabilities, significant increases in equipment investment, and complex operational management that require further optimization.
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Multifactor Metro Passenger Flow Prediction Model Based on XGBoost-ZOA--Taking Xi'an Metro as an Example

ZHENG Xuanchuan, QIN Yong, GUO Jianyuan, TONG Xin, HUANG Xiaolin

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To meet the demand for subway line passenger volume prediction under multiple factors, this paper selects 12 influencing feature indicators from the dimensions of time, weather, network scale, urban development, holidays and activities through feature mining and correlation analysis, Aiming at the problem of hyperparameter optimization of the XGBoost model, a hyperparameter optimization algorithm based on the zebra optimization algorithm (ZOA) is proposed; an XGBoost-ZOA combined prediction model is constructed, a cross-validation scheme for time series data prediction is designed, and an example verification is carried out in Xi"an Metro. The prediction model optimized by the ZOA algorithm has a prediction error MAPE of 3.85% on the Line 1 test set. Compared with the classic intelligent optimization algorithm, its prediction effect is the best, which confirms the superiority of the algorithm. The average MAPE of the XGBoost-ZOA combined prediction model on 9 lines reaches 5.18%, and the maximum error does not exceed 7%. The predicted value and the true value curve have a high degree of fit. Compared with the SARIMA model and LSTM model, MAPE is reduced by 1.12 and 1.45 percentage points respectively; RMSE is reduced by 10.8% and 13.6%, respectively. Finally, based on the feature importance index output by the model, the differentiated impact of various influencing characteristics on the passenger volume of each line is explained. The analysis results are highly consistent with the actual situation of each line, proving that the model has strong explanatory power and good practicality.
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Statistics and overview of China""s tourism rail transit project development in 2024

Lu Fang, Hu Jiangfeng, Wang Fei, Zhang Chen, Li Xiaojuan, Du Zhe

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In recent years, tourism has become a key pillar of China’s national economy, and the integration model of “transportation+tourism” has gradually taken shape. With advantages such as high capacity, speed, environmental sustainability, and strong sightseeing appeal, tourism rail transit is increasingly emerging as an effective means to meet the growing demand for high-quality tourism. This study compiles informal statistics on major tourism rail transit projects in China that are completed, under construction, or in the planning stage. As of the end of 2024, there are 23 completed projects, 10 under construction, and 38 in planning. The total length of the 33 completed and under-construction projects is approximately 621.864 km, comprising 265 stations, with a total investment exceeding 72 billion yuan. The paper also analyzes the key challenges facing the current development of tourism rail transit in China, including insufficient clarity in project positioning, difficulties in approval processes, high construction costs, and the lack of well-established standards and regulations.
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A Review of Research on the Optimization of Train Operation Planning in Urban Rail Transit

陶思宇, LIzhide

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Train scheduling optimization, as a core issue in urban rail transit transportation organization, is crucial for enhancing the operational efficiency and service quality of rail transit systems. To systematically review the research progress in this field and promote its further development, this paper provides a comprehensive survey of relevant literature both domestically and internationally. From the perspective of mathematical modeling, the paper summarizes the core elements of train scheduling optimization, including objective functions and constraints, from both the line-level and network-level perspectives. Furthermore, a detailed review of solution methods is presented, categorizing the approaches into heuristic algorithms and exact algorithms. Finally, the paper identifies existing research gaps and proposes future directions, including the need for improved modeling of dynamic passenger flow and behavior patterns, optimization of operations under network interconnection scenarios, exploration of multi-strategy operational models, and the integration of intelligent optimization algorithms, to further advance research on train scheduling optimization in urban rail transit.
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Optimization Design for the Signaling System Refurbishment of Tianjin-Binhai Light Rail under Strong Constraints

ZHANG Xiaolei, WU Jingjing, LIU Shuai, WU Qiuyan, Guo Bodi

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The refurbishment project for the signaling system of Tianjin-Binhai Light Rail Line 9 faces multiple significant constraints, including limitations imposed by the pre-station turnback, insufficient length of the train inspection shed and limited space in existing equipment rooms.These constraints significantly conflicted with the renovation objectives , such as 2-minute turnback interval, updating the automated inspection shed, and ensuring non-disruptive installation of new equipment, targeted optimization designs were therefore required .This study conducted a detailed analysis of how these constraints restricted conventional signaling system design. Key optimizations includes: adding the axle counter between the platform and the crossover switches, modifying the control logic of the crossover switches from double-acting to single-acting to shorten the alternating turnback interval; innovatively applying a safety braking model optimization strategy within the inspection shed, reducing train running speed, adjusting the C-track section interlocking logic, and optimizing the depot signaling design to minimize the protection distance for stopping in the B-track section and enable automatic entry/exit inspection shed functions; proposing a centralized station UPS/battery transitional access scheme and a remote power supply solution with equipment streamlining for non-centralized stations to address spatial limitations. Research indicates that these design optimizations have effectively resolved the conflict between stringent constraints and design objectives. The new system equipment has been deployed into operation, achieving a reduction in the minimum turnback interval from 136 seconds to 114 seconds, and decreasing the required protection distance for stopping in the B-track section from 7.56 meters to within 3.8 meters. The findings provide valuable references for signaling system renovation designs in similar project.
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Discussion on the Necessity of Setting up Piston Ventilation Ducts in Subway Stations in Severe Cold Regions

MA Xiao, HE Wei, XING Tianwen, 孟鑫, 李国庆

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In order to study the necessity of setting up piston ventilation ducts in metros in China's severe cold regions, this article selects typical station public areas and section tunnels of the operating Shenyang Metro Lines 1 and 9, and tests their temperature, carbon dioxide concentration, and inhalable particulate matter concentration under open ventilation operation in the hottest month and closed ventilation operation in the coldest month. Utilizing temperature as an indicator of the thermal environment, carbon dioxide concentration and inhalable particulate matter concentration as a measure of air quality, this research quantitatively analyzes the actual environmental control effect of the open ventilation system of the full-height non-enclosed platform doors in operating Shenyang Metro lines on the typical stations public areas and section tunnels. The findings suggest that the piston ventilation volume formed by the open ventilation system of the full-height non-enclosed platform doors in the Shenyang Metro within the section tunnels has exceeded the amount required for temperature control, indicating that the actual regulating capacity of the piston ventilation ducts on the thermal environment of the section tunnels is relatively weak. After closing the piston ventilation duct, the thermal environment and air quality can still meet the design specifications. For future metro lines in Shenyang, it may be advisable to cancel the piston ventilation ducts as an optimization design scheme of the piston ventilation system. The research approach in this paper can serve as a reference for the optimal design of piston ventilation systems in metros in other cities located in severe cold regions in China.
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Tool Study on Shield Cutting Bridge Pile Foundation in Mudstone Formation

shenyusheng

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In order to solve the technical problem that it is difficult to take into account the efficiency of pile foundation treatment and structural safety when shield structure penetrates the urban viaduct, this paper takes the background of Sichuan Normal University-Jiaozi Interchange Interval Project of Chengdu Railway Transportation Line 13, and conducts a research on the key problem of shield structure cutting reinforced concrete group piles continuously in mudstone stratum. Through innovative tool selection and construction control technology, a set of comprehensive solutions for shield structure pile cutting is established, which takes into account both construction efficiency and structural safety. The research adopts a combination of theoretical analysis and numerical simulation, and uses ABAQUS software to optimize the parameters of the shell cutter, such as the front angle, edge angle and edge width. The research results show that: ① shield cutter plate adopts 6 panels + 6 spokes composite cutter plate, and the pile cutting adopts double-sided blade shell knife with front angle -45°zero back angle, 90°blade angle, and 10mm blade width, which can improve the effect of shield pile cutting; ② the tool arrangement of hobbing knife+scraper knife+shell knife+precedent knife is designed, and the best effect of pile cutting is achieved by the improvement technology of the shield machine system and the construction control measures; ③ the maximum settlement of pile tops is only -2.81mm, and after stabilization, the settlement is controlled at -1.75mm; Counting discharged rebar, the length of rebar less than 750mm accounts for about 76.3%, and the fracture form of cut-off rebar accounts for about 70.1%, which indicates that the cutter tool arrangement is reasonable, and it can cut off most of the rebar efficiently, and at the same time, the effect on the top of the pile settlement is relatively small. The results of the study can provide a reference for the shield pile cutting method to continuously cut pile foundation in similar mudstone stratum.
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An Analogy-based Deducing Method of Short-Term Passenger Flow in Urban Rail Transit Delays

ZHANG Yuekun, LIU Jun, WANG Yueyue, YE Mingyu

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In the operation of ultra - large - scale urban rail transit networks, train operation delays occur frequently. Accurately and efficiently predicting the number and scope of affected passengers is crucial for network command and dispatch. Based on the normal passenger flow situation, this paper combines the advantages of data - driven and model - driven methods and proposes a short - term prediction method for the scope and number of affected passengers under urban rail train delays. First, based on the detailed OD path data of passenger travel chains under normal conditions, by analyzing the passenger flow direction in the delayed section, the scope of affected passengers is defined and a passenger flow quantity prediction model is constructed. Second, for the affected passenger group, according to the travel choice behavior of passengers under delay conditions, the passenger impedance sensitivity coefficient is calibrated to predict the structural changes of passenger components (waiting, detouring, and loss). Finally, multiple actual train delay scenarios in the Beijing urban rail network are selected for verification. The results show that this method can be effectively applied to multiple scenarios in the Beijing urban rail network. The average relative error of the prediction during the morning peak on weekdays is 4.8%. The time - consuming for predicting various passenger flow indicators within the next 30 minutes with a 5 - minute granularity does not exceed 140 seconds, which shows good universality, accuracy, and timeliness. Currently, this solution has been successfully applied in the Beijing Rail Transit Command Center, providing passenger flow risk warnings, passenger guidance, and emergency coordination support for network dispatchers.
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Research on Express/Slow Trains Operation Technology: A Case Study of Ningbo Metro Line 6

YE Ru, LYU Yingkang, HE Jidong, ZHAO Xinghua, WANG Yong, ZONG Erkai, JIANG Yue

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Ningbo’s urban rail transit construction faces the challenge of efficiently utilizing limited transportation corridor resources. To enhance the operational efficiency of Metro Line 6, research was conducted on express/local trains operation technology. The study evaluated the technical and economic feasibility of this model by examining:Technical aspects of express/local operation, Travel demand and operational plans, Overtaking station selection and track layouts, Time efficiency and economic benefits. Results show that adopting the express/local model on Line 6 achieves the planning goal of a "30-minute travel circle covering Ningbo’s six districts," offering significant competitive and economic advantages. Express commuter trains save 6 minutes per trip, while super-express trains save 12 minutes, generating an annual social value of approximately ￥48.2 million from reduced travel time.
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Financial Digital Transformation Practice of Guangzhou Metro Driven by Business-Finance Integration

WANG Xiaobin, HU Jinwei

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Ensuring financial sustainability through financial digital transformation constitutes an urgent requirement for urban rail transit enterprises, with business-finance integration serving as an effective enabler for such transformation. Current industry research predominantly focuses on technology applications in isolated operational scenarios while lacking comprehensive financial digital transformation frameworks; concurrently, studies on business-finance integration exhibit limited empirical research within rail transit contexts and emphasize unidirectional approaches. Addressing these gaps, this study employs a case analysis methodology centered on Guangzhou Metro’s implementation to investigate pathways and outcomes of bidirectional business-finance integrated financial digital transformation. Findings demonstrate that synergistic advancement of conceptual/systemic reforms, methodological transformation, and ecological restructuring effectively promotes organizational integration, information integration, and value convergence between business and finance functions, yielding significant outcomes: enhanced accounting information quality, development of cross-functional finance talent, strengthened business support, and deepened strategic alignment; financial processing efficiency improvements are manifested in a 5-day reduction of month-end closing cycles, 44% increase in per capita transaction document processing volume, and 52% rise in per capita voucher creation volume; cost-effectiveness is demonstrated through an 8.6% labor productivity gain and 9.2% reduction in cost-to-revenue ratio. A replicable four-component pathway is distilled: top-down design leadership→bidirectional business-finance integration→enhanced data governance→phased ecosystem synergy. This research establishes a theoretical framework and practical paradigm for urban rail transit enterprises to advance financial digital transformation.
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Optimizing the Passenger and Freight Mixed Transport Scheme of Cross-line Urban Rail Transit with Dynamic and Flexible Marshalling

YAO Jing, ZHANG Lanfang, YIN Haodong

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To address the issues of wasted capacity during off-peak hours in urban rail transit and the increasing urban logistics demand alongside worsening traffic congestion, this paper proposes an online flexible train formation optimization model for mixed passenger and freight transportation in urban rail transit. The research first analyzes the feasibility and necessity of implementing freight services in rail transit systems. Subsequently, a mixed passenger and freight transportation optimization model with online flexible train formation is constructed based on Y-shaped lines, and solved using the GUROBI solver. Results indicate that the flexible train formation scheme for mixed transportation can effectively match capacity with demand, reduce the number of trains required, achieve efficient capacity utilization, and enhance economic benefits through freight revenue, thus providing new perspectives for urban rail transit development.
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Analysis of the Impact of Shield Underpass Construction on the Substructure of Existing Bridges

lizhixiong, 李永骝, maowufeng, 向锦艳, 刘庭金, 蔡良怡

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Abstract:

Shield construction in the neighbouring bridge pile foundation, especially the close positive underpassing of bridge piles and the operation within 3.0m from the bridge pile foundation, has a significant impact on the bridge structure. Therefore, this thesis takes the actual project as the background and adopts the method of combining on-site monitoring and numerical analysis to investigate the effects of shield close underpassing construction on the deformation of the substructure of existing highway continuous girder bridges, the degree of disturbance of single piles, and the bearing capacity of pile foundations, and to classify the impact level of its effects. The results show that: (1) when the shield is tunneling in the middle weathered grey rock layer, when the horizontal clear distance is 0m, the single pile stress disturbance degree induced by the shield tunneling is larger, and its impact grade is strong impact. (2) When the shield is digging in strongly weathered grey rock layer, due to the insufficient residual bearing capacity of the pile foundation, its impact level is strong impact at 0~3.0m horizontally and 1.0m~3.0m vertically. (3) When the depth of pile foundation embedded rock is 1.0m, 2.0m, 4.0m induced single pile stress disturbance degree is large, and its impact level are all strong impact.
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Passenger flow prediction of rail transit based on improved particle swarm optimization algorithm to optimize SVR model

Song Hu, Zheng Chang, Bei Yang, Haipeng Wang, Jie Ma

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To address the challenges of accurately predicting passenger flow scale and supporting management decision-making for urban rail transit under fine-grained conditions, this study analyzes the spatiotemporal distribution characteristics of passenger flow and influencing factors based on automatic fare collection (AFC) data. The support vector machine regression (SVR) model is selected as the passenger flow prediction algorithm of rail transit, and the particle swarm optimization (PSO) algorithm is used to optimize the model parameters. Using passenger flow data from Beijing Metro Line 4 in October 2021, with a time granularity of 15 minutes for passenger flow statistics and prediction, three influencing factors of weather, time period and date type are taken as input variables for model prediction, the accuracy of the proposed model is verified by means of index evaluation (mean squared error, mean absolute error, coefficient of determination, and relative accuracy) and model comparison. The results demonstrate that the proposed model effectively captures the spatiotemporal characteristics of rail transit passenger flow and achieves high prediction accuracy, with a mean squared error of 0.0164 and a coefficient of determination of 0.93. Additionally, a positive correlation is observed between the error values of different model predictions and the scale of rail transit passenger flow. The research contributes to a deeper understanding of the distribution characteristics and evolution of urban rail transit passenger flow, and providing support for optimizing rail transit operation organization, scheduling strategies, and network planning.
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Intelligent Rail Transit Data Security Protection System: Challenges, Technologies, and Future Evolution

chenlei, yangyuxin, GongBei

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With the rapid advancement of intelligent rail transit systems, data security has become a core issue affecting the stable operation of these systems. This paper systematically reviews the research progress in the field of rail transit data security, providing a comprehensive analysis from data characteristics and security threats to protection technologies. The study reveals that rail transit data is characterized by multi-source heterogeneity, high real-time requirements, and strong sensitivity. It also identifies key risk points in data transmission, storage, and processing. In response to common threats such as cyberattacks and data breaches, this paper explores the current applications of cutting-edge protection technologies, including federated learning, lightweight encryption, and dynamic access control. Special attention is given to the applicability and performance of these technologies in resource-constrained rail transit environments. The research shows that federated learning effectively addresses the problem of data silos, improving model training efficiency while preserving privacy. Lightweight encryption algorithms demonstrate millisecond-level response advantages in trackside devices. Based on an analysis of technical bottlenecks and development trends, the paper further highlights that AI-powered proactive defense and cross-system collaborative governance will be key research directions in the future. The findings provide theoretical support and practical guidance for building a secure and intelligent rail transit data system.
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Research on Multi dimensional Comprehensive Matching Evaluation Method of Urban Rail Transit Capacity and Volume Based on Combination Weighting-TOPSIS Method

tianwanqi

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To comprehensively and accurately measure the spatiotemporal adaptability between urban rail transit capacity supply and actual dynamic multi-dimensional passenger flow demand is an effective way to optimize existing capacity configuration and solve the problem of network load imbalance. This article focuses on the evaluation of the matching degree between the transportation capacity and passenger flow demand of urban rail transit systems. A comprehensive evaluation is conducted from two dimensions: transportation capacity supply and passenger service level. It not only considers the utilization rate of transportation capacity, but also focuses on multiple indicators such as passenger service level (waiting time, congestion level); And achieve a three-level comprehensive evaluation of the matching degree of transportation capacity and volume from the station section line. Finally, an empirical analysis was conducted using a single line of Beijing Metro as an example to verify the accuracy and practicality of the proposed method. And provided targeted improvement suggestions.
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Research on the Potential Evaluation of Urban Rail Corridor Development Based on Node-Place Model: A Case Study of Three Typical Subway Lines in Guangzhou

Wang chengfang, 陈华馨, Wu Zichao

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In the era of stock-based development planning, urban rail transit serves as a critical driver for cities to achieve high-quality development, with significant potential embedded in areas along transit corridors. The Node-Place model, originally proposed for European railway station redevelopment, effectively captures the dynamic interplay between transportation and land use in station areas by balancing "node" (transportation accessibility) and "place" (functional vitality) values. This study transcends traditional isolated evaluation frameworks limited to station-level analyses, extending the Node-Place model application from micro-scale stations to meso-scale transit corridors. Taking three typical metro lines in Guangzhou as empirical cases, it dynamically identifies development potentials and constraints across corridor segments, enabling precise assessment of rail-space synergy. Through Kernel Density Analysis and quantitative corridor balance assessment methods, the research comparatively examines development disparities among corridors and evaluates station-specific potentials at a meso-scale. Optimized strategies tailored to each corridor’s characteristics are proposed, demonstrating the model’s reliability in meso-scale urban analyses. This methodological expansion provides actionable insights for coordinating transit infrastructure with spatial optimization in high-density cities.
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Platform Screen Door Controller Scheme Based on All-electronic Computer interlocking System

Luping, 师秀霞, 王瑞云

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With the popularization of fully automatic operation systems in major cities across China and the release of operational technologies and management specifications for these systems, the requirements for flexible marshalling, operational efficiency, reliability, availability, and safety continue to increase. Additionally, there is a growing amount of interactive information between signal systems and platform door systems. The traditional hardwired interface method can no longer meet the escalating user demands. Therefore, based on conventional platform screen door control systems, a platform screen door controller (PSDC) solution is proposed. This solution incorporates SIL4-level safety technology based on domestically produced hardware and software, and utilizes full-electronic computer interlocking. It replaces the traditional relay interface between signal systems and platform door systems, achieving an integrated design from logical processing to execution control and status monitoring. The PSDC adopts a fully electronic design, with single boards supporting hot-swapping, eliminating the need for regular maintenance. The system conducts real-time fault detection and provides timely alarms in the event of a failure.S Not only does this approach simplify the commissioning process for the interlocking of train doors and PSDs, but it also significantly reduces the interaction time between the signaling system and the PSD system, thereby enhancing the overall line"s operational efficiency and reducing headways.
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Research on Route Optimization for Talent Recruitment in Urban Rail Transit

liangying, liangyanjiao

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This study addresses the recruitment challenges of “difficulty in selecting and retaining talent” in China's urban rail transit industry. Using graduates from Beijing Jiaotong University employed by subway companies from 2018 to 2024 as a sample, a questionnaire surveyed five aspects: graduate profiles, employment locations, job - seeking processes, factors important to graduates, and job - fit. Based on 539 valid responses and a Logit model, a multi - dimensional analysis framework was created to identify key factors affecting recruitment. Results showed recruitment effectiveness depends on job location matching expectations, unit development aligning with career goals, knowledge and skills matching positions, and job identification and subjective evaluation. Accordingly, seven optimization strategies were proposed: improving job - education fit, focusing on job - seeking satisfaction, coordinating job locations with expectations, guiding job choices for different career expectations, matching job skills with graduate abilities, building a diverse talent ecosystem, and enhancing vocational planning education. These aim to provide evidence for the industry in formulating talent policies and improving recruitment efficiency.
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Research on the Signal System Data Transmission Capability Under 160 km/h Speed Level Using 5G Network Slicing Technology

RUAN Xiaofei, LIAO Zhibin, FU Song, WEI Guodong

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In response to the fundamental contradiction between the increasing demand for vehicle ground integrated communication services and limited frequency resources, the paper aims to research the solution of using 5G network slicing technology for signal system service transmission under the vehicle ground wireless communication architecture, and conduct actual verification. Analyzing the current demands and transmission system status of vehicle ground integrated communication services, propose the feasibility of using 5G network slicing technology to solve the problem, design the system from two aspects: network scheme and slicing scheme, and conduct field experiments based on Guangzhou Metro Line 18 to verify the transmission capability of 5G network slicing technology at an operating speed of 160km/h. The results indicate that the delay and packet loss rate of ordinary 5G network slices cannot satisfy the transmission requirements of signal systems in network congestion scenario; After configuring PRB reservation, the latency was significantly reduced, reaching 99.87% in less than 150ms, and the packet loss rate decreased from 1.55% to 0.08%, completely satisfied the transmission performance requirements of signal system services. In addition, when QoS strategies are adopted to increase the priority of signal system services, the transmission capacity can be further improved, and the latency continues to decrease by 39%. The percentage of data packets below 150ms increases to 99.99%, and the packet loss rate decreases from 0.08% to 0%. Therefore, 5G network slicing technology has the potential to transmit signal system services at a speed of 160km/h.
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Analysis and Treatment of Vibration and Noise of Short Sleeper Solid Concrete roadbed in Metroline

LIU Daotong, TAN Dazheng, HAN Zhaoxia, LIU Xin

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According to the complaints about the disturbance caused by vibration and noise along the short sleeper solid concrete roadbed of a subway operating line, the causes of vibration and noise problems are analyzed through the field investigation and vibration and noise test of the subway and sensitive points, and the corresponding measures are taken ,such as replacing the vibration damping fasteners, adjusting the bottom slope of the rail and grinding the rail. The stiffness design and vibration reduction effect of floating rail fasteners are predicted by establishing the vehicle-rail coupling analytical model and the tunnel-strata building finite element model. After the renovation, the vibration and noise test and home visit were carried out. The test results showed that after the renovation, the indoor vibration VLZmax of sensitive points was reduced by 6.4dB during the day and 8.3dB at night, and the equivalent sound pressure level of secondary structural noise was reduced by 1.36dB (A) during the day and 1.88dB (A) at night. Residents reported that the problem of vibration and noise was significantly improved. Effectively solve the problem of vibration and noise complaints. It can provide reference for solving similar complaints about subway vibration and noise in China.
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Research on the Optimization of Urban Rail Transit Train Timetable Based on Size Routing and Passenger Flow Control

JI Yingwen, LIU Lanfen

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Some major urban rail transit stations are severely congested during peak hours, and there is an urgent need to study train schedules from the aspects of large and small routing schemes and passenger flow control strategies. Taking urban rail transit lines during the morning rush hour as the research object, a train timetable optimization model is established with passenger travel costs and enterprise operating costs as objective functions, considering constraints such as departure intervals, train capacity, passenger flow control, and large and small routing schemes. Adopting a linear weighting method to balance passenger travel and enterprise operating costs, and designing a genetic algorithm for model solving, the Hangzhou Metro Line 4 was used as an example for verification. The results showed that optimizing the train timetable can reduce the cost of passenger travel, and the scheme of large and small routes can help enterprises reduce operating costs; Simultaneously considering passenger flow control can further alleviate congestion within the station. Based on the study of timetable optimization problems for large and small traffic routes and passenger flow control, it can provide support for the formulation of peak scheduling strategies for rail transit enterprises.
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Evaluation study of bus and subway transferring based on swipe card data -- A case study of Beijing

HUANG Kai, ZHANG Jianqin, Cheng Xinyue, HU Chaonan, HUANG Xinyi

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This study evaluates the coordination efficiency of urban public transportation systems by analyzing bus-subway transfer behavior characteristics, developing a bidirectional “subway-bus” transfer analysis framework based on Beijing's smart card data, which systematically defines subway-to-bus (STB) and bus-to-subway (BTS) transfer modes. An evaluation system encompassing 10 indicators—including transfer bus service area, competition intensity, and spatiotemporal distribution patterns—was constructed, with K-means clustering applied to classify subway stations. Key findings revealed that BTS transfers predominantly occurred during morning peaks while STB transfers concentrated in evening peaks, with both modes exhibiting a consistent 1:2 ratio in travel time and distance between bus and subway segments, alongside an average 6-minute bus waiting time for STB; spatially, high-demand bus transfers clustered around national railway hubs and sub-centers, with intense competition observed along the Tongzhou-Chaoyang corridor of Subway Line 1; clustering analysis categorized stations into five distinct types for each transfer mode, demonstrating tidal passenger flow-driven differentiation. The research provides theoretical and practical insights for optimizing transfer services and enhancing network coupling efficiency in megacities.
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Research on Train Operation Adjustment in Urban Rail Lines under Unidirectional Operation Interruption Scenarios Based on Virtual Coupling Technology

zhouweiteng, gaojie, lufang, hanbaoming, hujiangfeng

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To address the issues of reduced network transport capacity and increased operational safety risks caused by large-scale passenger stranding when unidirectional service interruptions occur on urban rail transit lines, this paper proposes a train operation adjustment strategy based on virtual coupling technology, wherein bidirectional trains are virtually coupled to traverse single-track sections, thereby enhancing line throughput. A mathematical model is developed to characterize the train adjustment process during virtual coupling, and an algorithm is designed for effective solution finding, validating the feasibility and effectiveness of the proposed strategy. Comparative analysis demonstrates that, relative to the traditional reverse-direction operation strategy, the proposed model reduces total passenger waiting time by 16.4% and station waiting time by 14.1%, effectively minimizing the number of stranded passengers. The strategy maximizes the transport efficiency of the interrupted line and significantly improves the flexibility and responsiveness of train operation adjustments.
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Optimization of Train Plan of Urban Railway Transit during the Gathering Stage of Large Special Event

XiaoQiqiang, Shi Jungang

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To alleviate platform congestion caused by quantities of passengers gathering at metro stations near event venues before large special event, a method of staggering the arrival time of upstream with downstream trains and designing the train skip-stop strategy is proposed, and an optimization model of the train diagram to minimize the risk of platform congestion, the skip-stop times of trains and the waiting time to leaving the platform of outbound passengers is established. In addition, an iterated local search algorithm adapting to the feature of passenger flow of large special event and timetable is designed to solve the problem. The algorithm searches neighbor solutions in two ways, one is by adjusting the running and servicing time of trains, the other is by adapting the stop plans of trains. A case using data of large special event held in Nanchang was used to test the effect of the optimization model and the algorithm. The results show that the heuristic algorithm obtains an excellent solution in a short time. After optimization, the max number of passengers on the platform decreased from 2 951 to 1 006, the average outbound waiting time significantly decreased 94.7 s and the risk of congestion on platform decreased 94%. And strategy of staggering the arrival time of trains and designing skip-stop can effectively reduce the time of passengers leaving the platform and relieve the congestion of the platform in metro stations around the scene during the eve of large special event held.
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TOD Planning Practice in the Urban Fringe Areas——Taking the Pingshan Section of Shenzhen Metro Line 16 as an Example

Ye Haifei, Zhang Bin, Xu xi

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The development level of transportation in the urban fringe areas is relatively low, and the construction of rail transit will further impact the existing transportation system. It is necessary to optimize the planning and layout of land along the rail transit line around the rail transit station, and create an efficient and dynamic TOD community that integrates rail transit with urban functions and transportation systems, so as to realize rail transit leading urban development. Taking the Pingshan section of Shenzhen Metro Line 16 as an example, based on the TOD planning and design theory, the TOD planning method along the rail transit line is systematically studied from three dimensions: rail station, station area and station group. After the implementation of the plan, a rail development axis of “four complementary areas and two-center linkage” will be formed along Metro Line 16, with differentiated mixed sharing of land use at each rail station, fine ecology of block building, and efficient rail connection and integration, so as to realize the TOD planning and guidance along the subway line and enhance the agglomeration and carrying capacity of the areas along the rail transit.
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Analysis of Carbon Emissions During the Construction Phases of Urban Rail Transit Stations, Sections, and Lines

Shi Xiyuan, 姚崇武, 林瑞敏, 田浩东, 蒲静, Guo Ru, 蔡辰, 黄翔峰

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This study addresses the issues of energy consumption and greenhouse gas emissions caused by the rapid development of urban rail transit and proposes a budget quota-based carbon emission accounting method for rail transit. By integrating carbon emission intensity and economic intensity indicators, a multi-level carbon emission analysis framework—comprising “station-section-line”—is constructed. Using the Fuzhou Metro Line 6 Phase I and its western extension project as a case study, the carbon emission characteristics during the construction phase of rail transit are quantitatively analyzed. The results indicate that the production of construction materials is the primary source of carbon emissions, accounting for 50% to 79% of total emissions, with steel reinforcement, concrete, and cement being the major contributing factors. At the station level, the carbon emission intensity per unit area ranges from 1.67 to 3.40 tCO?e/m2, influenced by station scale and structural design; the economic intensity ranges from 1.54 to 3.40 tCO?e per ten thousand yuan, mainly affected by the low-carbon level of rail transit technologies. At the section level, carbon emission intensity varies significantly with different construction methods. Sections using the cut-and-cover method exhibit higher carbon emissions, with the maximum reaching 36.5 tCO?e per double track meter, primarily due to higher demand for steel and concrete. This study provides a scientific basis for low-carbon construction throughout the lifecycle of urban rail transit, and holds significant theoretical and practical value for promoting the green and low-carbon transformation of the rail transit sector.
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Research and Development of New Type of Fasteners for Ballasted Track Sections

duanyuzhen, CHEN Peng

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In view of the problems of environment pollution, harm to the health of construction personnel, low efficiency and difficult to guarantee the anchoring quality when sulfur cement mortar is used in the construction of prestressed concrete sleeper fastenings of ballast ballast bed, a new type of fastenings system of ballast ballast bed is researched and developed. The fastening system adopts the technology of new composite casing embedded in the sleeper, eliminating the existing on-site anchoring step or the technology of embedding nylon casing. It is not only more environmentally friendly and efficient construction process, but also has simple structural design and convenient operation, which effectively improves the technological level of fastening installation and reduces the environmental burden.It significantly improves the installation quality, improves the construction efficiency and prolongs the service life.Under the background of the increasing emphasis on green construction and high-quality development in domestic urban rail transit construction, this technology has a very broad market prospect.
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Comparative Study on Synchronous Adjacent Construction of Shield Tunnel Underpassing Ventilation Shaft

heyonghui, wangchunsen

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To address the technical challenges of the synchronous close-proximity construction during the shield tunneling of Line 1 of the Dongguan Rail Transit in Guangdong Province, an analysis was conducted on the impact of the construction sequence of the shield tunnel and the intermediate ventilation shaft. A construction plan was proposed that would minimize impact and maximize economic benefits. Based on the actual site conditions, three construction plans were put forward: (1) involves constructing the ventilation shaft after the shield has passed through, (2) involves the shield passing through after the construction of the shaft's base slab is completed, (3) involves the shield passing through after the main construction of the shaft is completed. Through numerical simulation, the impact of different construction schemes on surface vertical displacement, wall top horizontal displacement, wall top vertical displacement, and support axial force was analyzed. From the perspective of impact and economic benefits, the optimal construction plan has been determined. Finally, the impact of the selected scheme and the reliability of numerical simulation were verified through field monitoring data. The research results indicate that the surface settlement and structural deformation are minimal after the main construction of the air shaft is completed and the shield machine passes through, although the construction period is longer. After the completion of the air shaft base slab construction, the construction period for the shield machine to pass through again and for the air shaft construction to be carried out after the shield machine passes through are similar, but the surface settlement and structural deformation are smaller after the shield machine passes through again following the completion of the air shaft base slab construction. This option also has higher economic benefits and is the preferred construction plan. The results of on-site monitoring indicate that all monitoring data are within the controlled range, the selected construction plan is safe and feasible, and the impact of construction is minimal. Additionally, the measured data were in good agreement with the numerical results, validating the reliability of the theoretical conclusions. The findings provide valuable reference for similar engineering projects.
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Research on Key Technologies of Urban Public Transport Network System Reconstruction and Hierarchical Bus Route Optimization under the Background of Rail Network

Yan Jianxin, WANG Tao

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Aiming at the problems such as unclear functions, unclear positioning, and insufficient integration with rail transit after the metro rail network is formed, From the "3-dimensional system, 2-dimensional line network, 1-dimensional line" multi-level, Refactored the integrated public transportation network system dominated by rail transit, Analyze the implementation strategy of rail-bus "dual network" integration in detail, Proposed a hierarchical and step-by-step optimization method and implementation path for the "express -trunk-branch" bus network, And apply theoretical methods to the reform of Chengdu"s public transportation network system. The research results indicate that the integration and coordination of Chengdu"s public transportation networks and the integration of rail transit "dual networks" have been significantly improved, This provides good reference value for the systematic construction of public transportation networks and the optimization of hierarchical public transportation networks in other large cities.
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Study on Classification Early Warning Evaluation Method of Subway Flood Disaster

YU Weizhi

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Currently, metro stations face challenges related to either insufficient or excessive responses in flood disaster early warning and emergency management. Achieving advanced dynamic classification for flood disaster early warning is a fundamental approach to preventing major flood incidents in metro stations. In this study, the early warning indicator system and quantification method for each warning indicator are developed based on the analysis of the disaster formation-prevention-resistance evolution mechanism of flood disasters in metro stations. The early warning indicator system includes the following three aspects: the risk of waterlogging and backflow, vulnerability, and disaster prevention and resistance capacities.Based on the relationship between hourly rainfall and meteorological warning levels with water accumulation depth, a quantitative method for assessing the risk of waterlogging and backflow in metro stations is proposed. The evaluation methods of vulnerability and disaster prevention-resistance capacities are proposed based on the Analytic Hierarchy Process (AHP) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). By considering the coupling relationships among waterlogging risk, vulnerability, and disaster prevention-resistance capacities, a comprehensive early warning value calculation method and warning level classification criteria for metro station flood disasters are established. Finally, the practical application of the proposed early warning evaluation method is demonstrated through two actual metro stations. The research outcomes can provide a decision-making support for advanced forecasting, early warning, and precise hierarchical response to flood disasters in metro stations.
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Discussion on Safety Evacuation of Passenger Flow in Metro Station

HE Lani, LIU Huijun

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In response to regulatory requirements for the safety evacuation of passenger flow in metro station, based on the location of emergency, this paper summarizes evacuation path and evacuation volume under different conditions. Discussing the method to calculating evacuation time which is in the code for safety evacuation, the view that safety evacuation simulation should be conducted is proposed. And the four key factors affecting the safety evacuation time in design stage are identified in this paper, mainly including evacuation volume, capacity of evacuation facilities, lifting height from the platform to the concourse or other safety zone, and distribution of evacuation facilities on the platform. By comparing the impact of escalator which is in the opposite direction on evacuation capacity, the rationality of using reverse escalator under the emergency evacuation condition are discussed. Considering on practical work experience, it is suggested that the timing of safety evacuation simulation should be advanced to the preliminary design stage.
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Overview of Underground Logistics Development Models Based on Urban Metro Networks

Feng Jianghong, Dai Cunjie

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The feasibility and practice of Metro-based Underground Logistics System (M-ULS) at home and abroad are elaborated, key node siting problems are categorized and shortcomings are pointed out, and influencing factors and benefits in the operation and organization of the system are integrated and compared. It also puts forward the medium- and long-term feasibility plan for the development of M-ULS, the future research direction of key node siting, and the influencing factors and improvement measures that need to be paid attention to in the process of operation. In addition, the existing research on this system is mostly carried out from the theoretical level, and the practical research is mostly at the initial stage of attempting to operate. Subsequent research not only needs to establish a perfect evaluation system to assess the types of transported goods and infrastructure conditions, but also needs to adopt a modern information-based operation and security system and formulate the corresponding standards of cargo transportation.
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Research on intelligent monitoring and authentication scheme of UAVs for rail transit equipment based on super SIM card and blinded ECDSA technology

孔令南, 冯国栋, 钱振东, 孙彭轩

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With the rapid development of the low-altitude economy and the rail transit industry, cross-domain integration has become a key driver of industrial innovation. The safety monitoring and maintenance of rail transit equipment demand a more efficient, low-power, and secure authentication mechanism. To address this need, this paper proposes a high-efficiency authentication scheme based on Super SM cards and blinded ECDSA technology. The scheme utilizes Super SIM cards as identity authentication carriers, integrates low-power Bluetooth technology for fast data exchange between devices, and employs the blinded ECDSA algorithm to enhance authentication security and resistance to attacks. Experimental results show that the proposed authentication scheme improves authentication efficiency by 43.8% while maintaining security. This scheme provides an innovative and feasible technical approach for the intelligent safety monitoring and maintenance of rail transit equipment, contributing to the overall security and operational efficiency of rail transit systems.
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Analysis of Rail Transit Line Closure Factors in Japan and Its Implications: A Case Study of Low-Ridership Lines

Ma Shiwei, Li Tengfei

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In response to the current situation where some rail transit lines face operational challenges due to continuously declining ridership, the study uses the evolutionary trajectory of Japan's rail transit development as an entry point. Through examining the evolution of Japan's rail transit development and employing multi-case comparative analysis, the research explores triggering factors, policy frameworks, and supporting measures for low-ridership line closures. The findings indicate that changes in demographic and industrial structure, along with transformation in travel modes, are key factors leading to continuous decline in rail transit ridership. Meanwhile, increased maintenance costs due to aging infrastructure and severe imbalance between revenue and expenditure have further deteriorated operational conditions. To address these issues, Japan has established evaluation systems centered on transport density for low-ridership lines at both policy and governance levels, along with implementing systematic governance solutions encompassing ridership cultivation and cost control. For lines requiring inevitable closure, innovative alternatives such as Bus Rapid Transit (BRT) dedicated lanes and demand-responsive transit have been adopted, effectively addressing the problems and ensuring basic mobility needs for residents along these corridors. Through comprehensive analysis of Japan's low-ridership rail transit closures and corresponding measures, the study summarizes experiences and implications, aiming to provide valuable references for future rail transit operation and transformation in China.
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From Underground to Airborne: Exploring the Integrated Applications of Low-altitude and Rail Transport

miaojia

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With the rapid acceleration of global urbanization, traditional rail transportation faces challenges in capacity bottlenecks and the need for efficiency improvements. The development of the low-altitude economy, particularly drones (UAVs) and electric vertical takeoff and landing aircraft (eVTOLs), provides new solutions for rail transportation systems. This paper explores the integration of the low-altitude economy with rail transportation, analyzing its potential in improving urban traffic efficiency and promoting the development of smart cities. The paper discusses the key technologies and practical applications of the integration from three aspects: the motivation for integration, technology, and application scenarios. By introducing visual perception, communication, control, multi-sensor fusion, and safety technologies, the low-altitude economy can enhance inspection efficiency, construction monitoring, and emergency response capabilities within rail transportation systems. This paper aims to provide a practical discussion on the integration of the low-altitude economy and rail transportation, further advancing the development of smart city transportation systems.
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Exploration on the Implementation Path of Comprehensive Development along Suburban Railways in China

CHEN Zhiqiang, ZHENG Xinming, ZHANG Ming, YANG Ze, ZHOU Peng

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As an important mode of transportation connecting the city center and surrounding areas, the development of urban suburban railways started relatively late compared to other transportation infrastructure. This situation has led to many suburban railway lines facing the dilemma of unstable passenger flow, high operating costs, and difficulty in covering revenue, with many lines even experiencing long-term operating losses. This article deeply analyzes the relevant policy orientation, development status and existing problems of railway comprehensive development, and specifically analyzes the successful cases of domestic railway land comprehensive development. It studies the functional layout of the industry based on the requirements of the upper-level planning, with "people" as the core, and the market trend-oriented comprehensive development planning design elements set. It also proposes innovative suggestions for the implementation path of land comprehensive development, providing theoretical support for the development of urban suburban railways in China.
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Adaptability Analysis of Tram Embedded Rail Track on Long-span Continuous Beam Bridge

SunKui

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In order to study the feasibility of laying the embedded rail track of tram on the continuous beam bridge, an embedded rail track-bridge element model is proposed. The static model of continuous welded rail(CWR) on continuous beam bridge is established. The longitudinal stress and deformation of CWR on the bridge under the temperature load are calculated. The beam-rail relative displacement is selected as the evaluation index to measure the rationality of the laying scheme of CWR on the bridge, and the influences of annual temperature difference of bridge, longitudinal resistance of polymer materials and laying scheme of rail expansion joint on the mechanic characteristics of CWR are analyzed in detail. The results show that the annual temperature difference of the bridge has a significant impact on the beam-rail relative displacement and the rail additional expansion force, which shows a linear increasing trend as the annual bridge temperature difference increases. And the rail additional expansion force and the relative displacement between the bridge and the rail reach their maximum values at the right beam joint of the second continuous beam bridge. When the annual temperature difference of the bridge is 30 ℃, the beam-rail relative displacement is 12.79mm, which exceeds the limit value of 6.20mm. It is difficult to control the relative displacement of beam and rail within the limit by adjusting the longitudinal resistance of polymer materials, so it is necessary to set a rail expansion joint on the bridge. It is recommended to set one grooved rail expansion joint at the right beam end of the 11th and 19th span bridges, so that the beam-rail relative displacement can meet the requirement.
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Research on the Construction of a Retrieval-Augmented Generation Knowledge Base for Urban Rail Transit LLMs Based on Knowledge Graphs

YU Songwei

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The data challenge has become the "final hurdle" for the deployment of metro-scale large language models (LLMs). This study constructs a deep knowledge graph with a "four-dimensional architecture" comprising classification framework, semantic benchmark, feature rules, and logical relationships. By adopting the "one-core, three-axes, and four-layer" framework to categorize industry entities, we establish a terminology dictionary, attribute repository, and entity-relationship tables, forming a knowledge architecture capable of engineering semantic interpretation. Based on this knowledge base serving as the domain knowledge hub for Retrieval-Augmented Generation (RAG) technology, we build a complete pipeline from data acquisition → structuring → vectorization → knowledge-enablement. The system packages domain knowledge into reusable knowledge units, providing LLMs with standardized, traceable, and rigorous domain expertise. This significantly enhances the reliability and compliance of metro LLM outputs, offering core support for the industry’s transition toward "data-driven" and "knowledge-driven" innovation.
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The Application of Light Public Key Infrastructure in Urban Rail Transit Networks

LiaoZhibin, CuiYibo, FengHaonan, GaoHongmin

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In order to solve the problem that urban rail transit safety-equipment transmission at risks in fake identify and information sniffing from rogue-device while work in open networks. This article proposes a system scheme for lightweight Public Key Infrastructure (PKI) based on domestic commercial cryptographic algorithms, which takes into account the certificate issuance scheme for administrative management needs. Based on the characteristics of rail transit, a layered SM2 signed X.509 certificate was designed for the equipment, and using the public key information in the certificate, the paper designed a three-way handshake protocol to negotiate session key in a fully open network space. And then, the paper designed handshaking communication processes for intra-domain and inter-domain device, and conducted the efficiency analysis. The results indicate that this system ensures point-to-point encrypted transmission between devices even in the communication information complete leakage situation.
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Application Research on New Water-proof Scheme of Construction Joint between Main Body and Accessory of Metro Station

huxianpeng

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Abstract: To solve the joints at the interface between the main body and the ancillary structure of the subway station cannot be pre embedded with embedded waterproof components, the author and their team have developed a slot type polymer coated waterstop and its supporting products and construction technology. The internal core material of the waterstop is made of 1mm thick steel plate pre processed into a "T" structure, surrounded by 1.2mm thick polymer waterproof and anti-corrosion coating. Using matching fixing glue to fix the cold joint section, using matching "L" - shaped connecting plates and matching connecting glue to connect the waterstop into a ring, achieving the middle buried waterstop of the cold joint. This new waterproofing solution has been tested in the laboratory and proven to effectively solve the problem of interface cold joint leakage in underground projects such as subways and civil air defense in Beijing, Xuzhou, Zhoukou, and other areas. It has good promotion and application significance and can be used as a reference for similar projects.
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A Study on the Robustness of the Bus-Metro Double-Layer Network in Chongqing"s Central Urban Area under Cascading Failures

wang gui lin, Mu Fengyun

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The robustness of transportation networks under emergency events is a key factor in assessing the resilience of urban public transportation systems. To study the emergency response capabilities and resilience performance of complex urban transportation systems during unexpected events, this paper takes the central urban area of Chongqing as the study region. A bus-subway two-layer transportation network model is constructed based on complex network theory to evaluate the robustness and emergency response capabilities of the urban transportation system under different shock modes. Through simulation analysis, the paper delves into the disaster evolution mechanisms and resilience trends of the two-layer network, and investigates the emergency coordination capabilities of subway and bus lines. In response to the vulnerability of single networks in current urban transportation systems during emergencies, an improved load-capacity model is proposed and used to analyze the network resilience under different attack modes. The study results show that: (1) The two-layer network exhibits a slower decline in network efficiency under both shock modes, with its redundancy and multi-path characteristics effectively mitigating the collapse process; (2) In the cascading failure process, the robustness of the two-layer network is consistently superior to that of single bus and subway networks, and the cascading failure caused by the failure of important stations has a more significant impact on network connectivity and efficiency; (3) The two-layer network is more effective in maintaining network connectivity and operational efficiency, especially when facing unexpected events, demonstrating stronger adaptive capacity and robustness. It can effectively share the load, alleviate congestion in single networks, and improve emergency handling efficiency.
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Research and application of digital collaborative design for subway stationentrance and exit

ZHENG Guangliang, WANG Jingchao, Lu Ruiquan, Yang Liu

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With the strategy of "smart city" and "digital city" put forward, digital design has gradually become an important direction to promote the reform of urban rail transit engineering construction. Aiming at the problems of low degree of cooperation among different disciplines and low efficiency in digital design of subway station entrances and exits, this paper puts forward a digital collaborative design method for subway station entrances and exits. Based on the method, we establish a collaborative way of professional data of entrances and exits architecture and structure, an then we develop a digital collaborative intelligent design tool for subway station entrances and exits based on general BIM design software. We take the entrance and exit of the newly-built station of Qingdao subway as an example for engineering application. The results show that the digital collaborative design method proposed in this study provides a new idea and framework for the digital design of urban rail transit, and the intelligent design tool for entrance and exit collaboration enables the BIM model designed by architectural and structural professionals to be lossless, quickly transmitted and collaborative between them. The method and design tool greatly improve the efficiency of collaborative design and promote the development of digital design of urban rail transit projects.
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Research on the Grounding System of Dual Flow Trains

daijun, 刘炜, 李明泽

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Unreasonable grounding system can cause problems such as increased train axle potential and circular current, as well as bearing erosion, deteriorating the electromagnetic environment of on-board electronic equipment, and thus pose a threat to the safety of train operation. Therefore, it is necessary to design the train grounding system appropriately. First, uniform chain circuit model is used to model the traction power supply system and dual current train grounding system. Secondly, through traction and power supply calculations, the train current can be obtained. Taking train current as the excitation source, the distribution of train axle voltage and circular current can be obtained. Take the currents of grounding resistors as a measure of the vehicle circular current distribution. Finally, PSO algorithm is used to optimize the train grounding system. After the optimization, the maximum circular current is decreased by about 20%, and the maximum vehicle axle voltage declines slightly. The optimization of the train grounding system in this article presents a guide for the design of the grounding system for dual flow trains, as well as provides a reference for other trains.
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A current balancing control strategy for urban rail bidirectional converters based on Modified voltage command

Wang Yong, Yang Duo, Zhang Jingpeng, Zhong Zhihong

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Bidirectional substation has advantages in regenerative braking energy utilization of urban rail transit because of its controllable output voltage, unit power factor operation and bidirectional energy flow. Due to the error of the voltage sensor and the inconsistency of the line parameters, the two converters in the substation will produce large unbalanced current, and increasing the feedback coefficient of the output current of the converter can reduce the current difference between the converters, but the fluctuation degree of the output voltage of the substation will be aggravated. On the basis of sag control strategy based on converter output current feedback, a sag control strategy based on substation output current compensating voltage command value is proposed by adding a voltage compensation term proportional to substation output current. The results show that this strategy can improve the current balance between converters and reduce the fluctuation degree of substation output voltage. Finally, the simulation model is built in MATLAB/Simulink, and the example analysis is carried out to verify the effectiveness of the proposed strategy.
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Research on Energy-Saving Control Methods for Subway Platform Lighting

ZhangNing

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The current lighting control methods for subway platforms exhibit issues such as simplistic control mechanisms and low control accuracy, resulting in severe energy wastage and an inability to provide a comfortable lighting environment for passengers. This paper proposes an energy-saving lighting control method for subway platforms based on passenger density, taking into account the characteristics of passenger flow, functional features of platform areas, and passengers' psychological needs. Firstly, by analyzing the spatial characteristics of subway platforms and the temporal psychological changes of passengers, a functional relationship between passenger density in different areas at different times and platform area illuminance is established. Subsequently, a linear programming optimization model is constructed with the goal of minimizing platform lighting energy consumption, constrained by platform illuminance requirements and using the lighting fixture dimming coefficient as the control variable. Finally, the simplex method is employed to solve the model, followed by a case analysis. The results indicate that, compared to full load (all lights on) control methods, the proposed method reduces platform lighting energy consumption by 32.96%, 38.39%, and 59.44% during morning peak, evening peak, and off-peak periods, respectively, while ensuring that the area illuminance remains within a reasonable range. This method effectively reduces subway platform lighting energy consumption and improves the comfort of the platform lighting environment.
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Optimization of Overspeed Protection Control Strategy for ATC System in Low Adhesion Environment

Pan Hongliang, Sun Minda, Li Di, Lin Yuanqiao, Yuan Jianjun

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In adverse weather conditions such as rain and snow, the adhesion characteristics between wheels and rails of urban rail transit trains differ significantly from those in dry and clear operating environments. To ensure the effective operation of overspeed protection of the Automatic Train Control (ATC) System under such conditions, it is of great essentiality to conduct in-depth research on optimizing the ATC overspeed protection control strategy in low-adhesion environments. The role of the overspeed protection function of the ATC system is elaborated from the following three perspectives: Safety Braking Model, Guaranteed Emergency Braking Rate (GEBR), and adhesion braking mechanism. By analyzing the contradictory relationship between the methods used to determine the GEBR value in specific projects and the adhesion coefficient in actual operations, potential failure mechanisms of the system’s overspeed protection function are explored. A simulation model for the overspeed protection of the ATC system, considering the influence of wheel-rail adhesion, is developed and validated on the MATLAB platform. Addressing the limitations of the current system’s train control strategy under rainy and snowy weather conditions, an optimized control strategy for ATC system overspeed protection in low-adhesion environments is proposed. This strategy enables the fine-tuned adjustment and control of GEBR value and system canopy speed under fixed target conditions.
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Research on the Target Speed Values of the Railway from Fuping (Yanliang) to Xianyang Airport

zouyu

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To solve the problem of selecting speed target values for intercity and city area composite functional lines in urban agglomerations, this paper takes the Fuping (Yanliang) to Xianyang Airport Railway (Fuji Railway) in the Guanzhong City Cluster as an example, and systematically analyzes that the line is positioned as an intercity line that takes into account the city area function, while reserving the function of crossing the west extension high-speed railway into the airport. It belongs to the urban area composite functional line. Against the background of the planning adjustment of the Fuji Railway, the paper systematically studies the travel time target requirements of the Xi'an urban agglomeration, and uses the scheme comparison method to propose three speed schemes of 140, 160, and 200km/h based on the distance between stations along the entire line for comprehensive comparison. Based on six factors including time target, line conditions, speed effect, traction energy consumption, engineering investment, and the impact of high-speed railway offline, etc. A comprehensive study was conducted on the aspect, and the results showed that although the target speed of 160km/h increased by 73 million yuan in investment compared to 140km/h, The traction energy consumption has increased by 9.55%, but the speed ratio of the entire line has reached 44.96%, which is within a reasonable range of 30% -50%. The effect of improving driving efficiency and shortening operating time is more obvious, which can meet the needs of entering the central area in 30 minutes and entering the core area in 45 minutes. According to the offline of the West Extension High speed Railway, the direct speed of 160km/h has only increased by 27 seconds compared to 200km/h, but has increased by 3.82 minutes compared to 140km/h. The effect is significant, and it can provide high-quality services for passengers traveling long distances. The line is suitable for the target speed of 160km/h. In the context of improving the quality and efficiency of power lines, the number of lines that integrate multiple functions will further increase. The research ideas of this paper can provide reference for subsequent projects.
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Evaluation Model of Urban Rail Transit Construction Project Selection Based on Analytic Network Process

Zhao Qian, Fan Xueyan, Tian Li

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The difficulty of urban rail transit construction planning project selection has increased significantly, as a result of the refinement of approval policies and the increase in the urban rail transit network scale. Therefore, the traditional qualitative analysis and comparison method cannot meet the requirements of construction planning project selection. To address the difficulty in selecting urban rail transit projects in large cities, a model for evaluating the selection of urban rail transit construction projects was constructed based on the analytic network process(ANP). Based on the policy requirements and the demands of relevant stakeholders, five evaluation criteria are proposed: urban coordination, social impact, construction implementation cost-effectiveness, post-construction traffic effects, and network service improvement. These criteria are further refined into nine evaluation indicators. An evaluation model operation platform was constructed based on MATLAB, and the evaluation model was verified using a city in Southwest China as a case study. The technical route of the evaluation model conforms to the decision-making logic for selecting urban rail transit construction planning projects. The input data of the evaluation model are all data that can be obtained during the construction planning phase. The output results of the evaluation model can intuitively reflect the priority ranking of the candidate projects.
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Soil displacement in unsaturated clay caused by double-line horizontal shield construction

LI Xuegang, CHEN Xiaofei, WEN Xiaodong, WANG Chaowei

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It is very important to study the formation displacement caused by double-line shield construction and its mutual influence for ensuring construction safety and improving construction efficiency. In this paper, based on the initial solution of unsaturated soil under buried depth load, the three-dimensional solution of formation displacement caused by double-line parallel shield tunnel construction is derived by superposition calculation of soil settlement caused by successive shield tunnel construction, and the influential factors such as incision construction load and soil loss are fully considered. The rationality of the solution in this paper is verified by comparing the results with actual engineering cases. The influence of construction parameters of double-line shield tunnel on formation displacement is further studied. It is found that the construction of advance line has significant influence on the construction of rear line, and the settlement peak value caused by double-line shield tunnel is shifted
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Prefabricated Facade Design of Urban Rail Transit Elevated Station based on Concrete Plasticity

Wan Zhanzhi, Lv Jiayue, Zhou Tiejun, Huang Shengxiang, Wang Ziyao

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The facade of the building is an important part of the image and urban style of the elevated station, and it plays a crucial role in the design of the station form. This paper firstly analyzes the existing situation and problems of the facade of the elevated station through on-site investigation. Subsequently, the assembly technology is applied to the construction of elevated stations. The plasticity of concrete provides a new possibility for the innovation of the form design of elevated stations. On this basis, the design strategy of the station facade is put forward from the perspectives of design and construction respectively. In order to demonstrate the pertinence and effectiveness of the design strategy of the facade of the elevated station, the design practice is carried out in combination with the engineering projects of Dayanhe Street Station and Xiuhu Station of Zhejiang Jinyi East Urban Rail Transit. Finally, the organic balance between the diversity of station facade design and the standardization of assembled components is realized. The research results can provide important reference value and guiding significance for the design and construction of the facade of urban rail transit elevated stations.
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Study on the Setting Of Rail Cant under Dynamic Changes in Wheel Profile

Zhu Aihua, Li Yuhang, Meng Yuxuan, Xing Tong, Bai Tangbo

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In response to the problem of setting rail cant under the dynamic changes of subway wheel profile, this paper measured the wear profile data of LM wheels at five operating mileage, established a subway vehicle system dynamics model, and analyzed the influence of rail cant on the vehicle's straight-line stability and curve passing performance during the dynamic changes of wheel profile; The entropy weight method is used to comprehensively evaluate the dynamic performance of the vehicle, and the optimal rail cant setting scheme is obtained for straight lines and curves with different radii under the dynamic changes of the wheel profile. Research has shown that when a vehicle is running in a straight line, the coupling of rail cant and wheel wear profile has a more significant impact on lateral stability than vertical stability. The dynamic changes in the wheel profile exacerbate the impact of rail cant on vehicle stability. During the curve operation, when rail cant is constant, the vehicle's curve negotiation performance first deteriorates, then improves, and then deteriorates as the wheel wear profile dynamically changes; When the wheel wear profile is constant, as the curve radius increases, the influence of the rail cant on the vehicle's curve negotiation performance gradually increases. Taking into account the dynamic changes in the wheel profile, the optimal matching of the outer/inner rail cant for straight, R300m, R400m, R500m, and R600m curve is (1/30, 1/40), (1/20, 1/20), (1/20, 1/40), (1/40, 1/40), and (1/40, 1/40), respectively.
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Theoretical Innovation Directions for Existing Urban Rail Line Reconstruction

DING Shukui

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With the rapid development of urban rail transit in China, the reconstruction of existing lines has emerged as a critical approach to enhancing operational efficiency, service quality, and safety reliability. Addressing the current challenges in urban rail transit line reconstruction, such as insufficient network synergy, path dependency in equipment updates, and the lack of upgradability design, this paper explores theoretical innovation directions. This paper proposes key strategies, including incorporating upgradability into the equipment performance evaluation system, decoupling equipment from lines for network-oriented reconstruction, and improving the overall network functionality through clustered line reconstruction. These theoretical innovations aim to systematically promote the reconstruction of existing lines, reduce the cost of equipment upgrades, improve maintenance efficiency, and drive the sustainable development of the urban rail transit industry.
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Key Technologies for Shield Tunnel Protection in Near-Zero Distance Deep Excavation Construction

GU Xintian, 金浩, 沈晓伟, 李奎

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In order to complete protection challenges of the shield tunnel structure under the condition of low clearance by the retaining walls construction and the near-zero distance deep excavation, taking the pump well construction project in soft soil area as an example, we used Metro Jet System method within steel H-piles driving by resonance free vibratory hammer, applied synchronous pre-reinforcement from the inside of shield tunnel by longitudinal braces, filament wound profiles etc. By comparison of 3D numerical simulation analysis and deformation monitoring, it has limited the influence of soil squeezing effect and time-space effect on the tunnel structure, which can provide a reference for the design and construction of similar projects in the future.
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Multi dimensional research on the economic cost-effectiveness of urban rail transit based on sustainable development

LIU Liqin, XING Yanting, YU Songwei, LI Mingyang, LIU Wei

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The positive externality of urban rail transit determines that a comprehensive economic cost-benefit analysis should be carried out when judging the economic feasibility of the project. In response to the latest requirements for preparing the outline and explanation of the project feasibility report, this study conducted a multidimensional study on the economic cost-benefit of urban rail transit. Firstly, identify economic costs and benefits from three dimensions: government, enterprises, and the public, establish a three-level quantitative+qualitative indicator system, expand quantitative indicators from 5 to 13, and add 14 qualitative indicators; Secondly, conduct research on key indicator analysis methods, propose quantitative methods for driving GDP, fiscal revenue, and increasing employment, break through the current difficulties in evaluating the macroeconomic contribution of urban rail transit, and improve the calculation methods for time saving benefits, fatigue reduction benefits, and traffic accident reduction benefits; Finally, it is clarified that there are 9 indicators that can be included and 4 indicators that cannot be included in the economic cost-benefit analysis flow table, and a comprehensive evaluation of the project's economic cost-benefit is conducted through case studies to provide support for early-stage decision-making and promote sustainable development of the industry.
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Research on the Planning and Design of Multi line Transfer Hubs in Rail Transit: A Case Study of Gangxia North Rail Transit Hub in Shenzhen

he long qing, cui xiao tian, Shi Qing, GUOJIAYING

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The high passenger flow and complex traffic organization of urban rail transit third line and above rail hubs directly affect the success or failure of hub construction, and the quality of planning and design schemes is crucial. This paper discusses the planning and design practices of the Gangxia North Transit Hub in Shenzhen as a case study. It elaborates on the planning methods and technical system for creating integrated urban transit hubs in the core areas of major cities, touching on aspects such as the functional positioning analysis of the hub, passenger flow demand forecasting, overall planning layout, comprehensive development of the hub, underground space planning, and improvements to the surrounding road traffic. The planning and construction of multi-line rail transit interchange hubs play a significant role in promoting the integration of stations and cities, invigorating urban development vitality in the area, guiding the transformation of urban transportation development models, and fostering the sustainable development of urban rail transit.
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Exploration of Travel Patterns of Urban Rail Transit Commuters: A Case Study of Changsha, China

DENG Jierong, LIU Chenhui

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This study analyzes the commuting patterns of metro passengers and explores the characteristics of each type of commuter based on the Changsha Metro AFC data from 2023. A Gaussian Mixture Model (GMM) is constructed using three variables: the median of the first boarding time, the median of the last boarding time, and the average commuting time. This model classifies passengers into three categories: the classic commuting pattern, the off-peak commuting pattern, and the long-distance commuting pattern. The results show that most passengers follow the classic commuting pattern, the off-peak commuting pattern is the second most common, and the long-distance commuting pattern is the least common. Passengers in the classic and long-distance patterns primarily commute during the regular peak periods (7:30-8:30 AM, 5:30-6:30 PM), while those in the off-peak pattern avoid these peak times, boarding to work time are more evenly distributed, covering the period from 7:00 to 12:00AM, and boarding from work time mostly between 8:00 and 10:00 PM. Regarding commuting time, passengers in the classic and off-peak patterns typically commute for 15 to 30 minutes, whereas those in the long-distance pattern usually commute for more than 30 minutes, with their alighting time also occurring slightly earlier.
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Overview of urban rail transit operation lines in mainland China in 2024

HouXiufang

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By the end of 2024, a total of 28 provinces and 58 cities in mainland China had opened 362 urban rail transit lines, with a total scale of 12168.77km, including 9281.37km subway lines, accounting for 76.27%. At the end of the statistical period, 1486.01km of FAO lines have been opened, accounting for 12.21% of the total mileage of lines in operation. In 2024, a total of 51 new urban rail transit operation lines (sections) were added, with a total length of 953.04km, including738.26km new metro lines and 425.70km new FAO lines, all of newly addded FAO lines were classified as GoA4. It is expected that by the end of the 14th Five Year Plan period, the total operating scale of urban rail transit in mainland china will exceed 13200km. It is estimated that the annual passenger volume in the year of the end of the
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Statistical Analysis of Urban Rail Transit Operation in the World in 2024: A Review

Han baoming, Lizhuoyi, Jinyuxin, Lufang, Hujiangfeng, Huangsiqi, Wangdingning, Zhangzhi, Gaojie, Fengfangwei

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With reference to the more common statistical standards in the international arena, urban rail transit is divided into three major categories, namely metro, light rail and tram, and the current status of the world''s urban rail transit operation is statistically analyzed. The analysis shows that by the end of 2024, 563 cities in 79 countries and regions around the world have opened urban rail transit systems, with a total mileage of more than 44738.97 km, of which subways, light rails, and streetcars each account for 51.23%,10.33% and 38.35%. As of December 31, 2024, 66 cities in China (including Hong Kong, Macao and Taiwan) have opened and operated rail transit, with an operating mileage of 12853.40 km, of which the operating mileage in Mainland China is 11,232.65 km. In 2023, the metros of 188 cities in 59 countries around the world transported a total of 713,78 million passengers, with an average load intensity of 0.85 million (passengers/day). kilometers), of which China (including Hong Kong, Macao and Taiwan) metro annual passenger traffic is 31.81 billion. China''s urban rail transit continues to develop steadily, and the scale of line network and passenger flow continues to rank first in the world. A total of 219 cities in 54 countries and regions around the world have opened suburban railways with a total mileage of 64,086.30 km, and 17 cities in China (including Hong Kong, Macao and Taiwan) have opened with an operating mileage of 2,865.47 km. By analyzing the scale and development of the line network in key countries at home and abroad, The construction of suburban railways in China and the interconnection between different networks have great prospects.
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Research on the Scope of Urban Rail Transit Control and Protection Area in Karst Region

yang zhihui, lei gang

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A specific adjustment plan for the control and protection area in karst region was proposed in response to the problem that the degree of expansion of the control and protection area for urban rail transit in karst geology was unclear. Starting from the mechanism of karst adverse geology affecting the safety of existing structures, through the study of guiding industry standards and the mechanism of karst ground collapse, three important indicators of the scope of control and protection area for urban rail transit in karst region were determined: the scope of influence of external operations, the scope of influence of karst ground collapse and the scope of susceptibility to influence of existing urban rail transit structures. Based on geometric analysis, the maximum scope where the existing urban rail structure suffered a safety risk caused by karst ground collapsekarst, which is induced by external operations, is determined. This maxium scope is adopted as the scope of the control and protection area in the karst region. Finally, the control and protected area scope calculation models of metro station and interval tunnels in two typical karst geological conditions are proposed. Calculations were carried out on Shenzhen Rail Transit Line 16 as an example, and the results can provide a reference for the operation and management of urban rail transit projects in Shenzhen and other karst regions.
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Prediction method of tunnel settlement in proximity engineering based on multi-source weighted data and automated machine learning

Yuzhen Han, Xiaofan Nie, Fucai Hua, Jizhong He, Lianwei Zhang, Hao Pan, Lei Zhang, Xuyang Wang

Abstract: (81) HTML (0) PDF (0.00 ByteKB) (0)

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To address the issue of settlement in existing subway tunnels due to the construction of new adjacent tunnels, an automated machine learning approach and a strategy for weighting multi-source data were employed. A predictive model was developed, taking into account tunnel characteristics, stratum properties, and relative positional relationships as input parameters, with the settlement values of the existing tunnels as the output. The model was tested using tens of thousands of simulation data points and real-world data. The findings suggest that while the automated machine learning algorithm can produce a highly accurate predictive model based on simulation data, it may not perform as well with multi-source data sets. By assigning weights to multi-source data, the model's ability to generalize can be improved, leading to an optimized model that specializes in real-world data, based on simulation data. When the quantity of weighted real-world data is comparable to the simulation data, the model's error rate is reduced. Additionally, according to the feature importance of the best-performing model, the stratum loss rate emerges as a critical input parameter for prediction, with the significance of geological conditions, spatial relationships, and construction attributes being nearly equivalent.
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Research on 3D Visualization Monitoring and Fault Diagnosis Method for Urban Rail Transit Switch Machines Based on Digital Twins

ZHENG Yan, ZHANG Zhenhai, LIANG Zhaohui, ma zhang

Abstract: (320) HTML (0) PDF (0.00 ByteKB) (0)

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In order to improve the visualization of switch machine status monitoring and the intelligence of fault diagnosis by urban rail transit operators, a 3D visualization monitoring and fault diagnosis method of switch machine based on digital twin is proposed, which provides a powerful technical support for the real-time monitoring of switch machine status, high-quality transmission of operation data, and the precise alarm of equipment faults. Compared with the existing intelligent operation and maintenance system of Switch Machines, this study uses digital twin technology to establish a high-fidelity model, maps the field-working Switch Machines in the information space through real-time interaction of data, and realizes three-dimensional visual monitoring of Switch Machines indoors through WebGL and model lightening technology; in view of the small number of samples of fault data of Switch Machines in the field, it establishes a combined model of CNN-Transformer to achieve fault diagnosis. To achieve the fault diagnosis of Switch Machines, the fault diagnosis accuracy rate is 98.67% under the condition of imbalance between normal data and fault data; In order to verify the feasibility of the proposed framework and the improved algorithmic approach, a 3D visualization monitoring and fault diagnosis platform for Switch Machines based on digital twins is designed.
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A Review of Domestic Research on Performance Evaluation of Urban Rail Transit Networks

Zhao Jiaxu, Hou Benwei, Miao Huiquan, Jiang Zhiwei

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In order to analyze the development and current research status of urban rail transit network performance evaluation, this paper conducts a quantitative analysis of the literature from the CNKI database based on CiteSpace software. This paper gradually focuses on three levels of research: urban rail transit, urban rail transit network, and urban rail transit network performance evaluation, and analyzes the information such as the number of publications, authors, literature sources and keywords. By tracing the important literature, the main indicators of rail transit network performance evaluation are summarized, and the advantages and disadvantages of different evaluation methods are commented. The results show that the research on performance evaluation of urban rail transit networks is undergoing several important transformations. Firstly, the analytical model is developed from unweighted network to weighted network model, which pays more attention to the differences between stations and intervals. Secondly, the research object was extended from the analysis of rail transit network to the comprehensive evaluation of coupled transportation networks such as rail-road and rail-bus. Finally, the research focus of network performance has gradually shifted from the resistance ability under disasters or external shocks to the resilience evaluation including the post-disaster recovery ability.
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Application research of Unmanned Aerial Vehicle Video Intelligent Inspection system in Low Altitude+Straddle Type Monorail Transportation

wushuqiang

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In recent years, promoting industrial innovation through technological innovation and developing new quality productivity as a new growth point for the national economy have become increasingly important in various industries. Low altitude economy has become a new industry direction pursued by global competition due to its prominent features. The research on low altitude economy in the field of urban rail transit is rapidly developing and growing. For the low and medium capacity rail transit system represented by the straddle type monorail system, based on the key technology research of low altitude technology, it is necessary to explore a low altitude unmanned aerial vehicle intelligent inspection system that is suitable for the construction and operation characteristics of straddle type monorail, meets operational requirements, and effectively solves maintenance problems. This article proposes for the first time a video intelligent inspection system based on unmanned aerial vehicle platform applied to straddle type monorail transit, analyzes its application plan and value in straddle type monorail transit, and explores a practical and feasible low altitude economic application scenario for the low and medium capacity rail transit system mainly based on elevated laying, which is conducive to realizing the automation of straddle type monorail transit track beams and bridges. Inspection Reducing the workload of manual inspections and minimizing manual omissions has important guiding significance.
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Research on Diffusion Mechanism of Backfill Grouting for Metro Tunnels During Operation Period

HAN Zhen, WEI Xueda, CHEN Tielin, WANG Shunyu

Abstract: (102) HTML (0) PDF (0.00 ByteKB) (0)

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In order to study the diffusion mechanism of slurry of backfill grouting for metro tunnel in different working conditions, the mathematical model of the diffusion process is derived according to the physical process involved in grouting, and a three-dimensional numerical calculation program based on the finite element method and the fluid volume method is compiled. Taking the actual project as the background, the diffusion behavior of backfill grouting for metro tunnel under different soil conditions is simulated, and the rationality of the numerical simulation results is verified by indoor model test. The results show that in hard soil, the slurry mainly splits in the direction perpendicular to the lining structure, and it is difficult to form a large area of closed reinforcement behind the lining. In the soft soil, with the increase of grouting pressure, the slurry gradually expands along the interface between the tunnel and the soil. After the grouting is completed, the slurry forms a uniformly distributed closed reinforcement along the tunnel wall. The trend of the model test is the same as that of the numerical simulation, which proves the correctness of the grouting diffusion mechanism behind the tunnel wall.
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Application Research on integrated automation intelligent operation and maintenance system of urban rail substation

GUO Zhiqi

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Through the introduction of intelligent equipment and advanced information technology, to improve the intelligent level of the power supply system of the whole urban rail transit (hereinafter referred to as rail"). Of city rail substation integrated automation intelligent operations system present situation and progress of the research, from the system architecture, hardware configuration, information conditions, scheduling mode, operational management, summarizes the current situation of the city rail substation integrated automation system dispatching, operational mode of pain points, put forward the city rail substation integrated automation intelligent operational system requirements. The overall framework of the integrated automation intelligent operation and maintenance system of the urban rail substation is designed, With the help of advanced information technology, Introduce intelligent equipment technology and establish the basic layer of independent intelligent component data acquisition, The integrated automation system of the substation integrates the decentralized construction of each electronic supply system and forms a unified dispatching and operation and maintenance platform ; Integrate the equipment full life cycle data of the power supply and distribution side of the urban rail power supply system, Build the intelligent operation and maintenance system of substation integrated automation system in the field of urban rail power supply, Suitable for the technical specifications for urban rail cloud, Form a unified intelligent power supply system platform, Solve the problems of decentralized construction of urban rail power supply system, ununified standards,repeated input of multiple subsystems and the access requirements of key equipment, In line with the current and future development needs of the intelligent power supply system.
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Service Quality Evaluation and Optimisation Strategies for Railway Stations Based on IPA-KANO Model-- A case study of Shenzhen and Hong Kong Metro Stations

YIN Longbiao, SONG Bingjing, LUO Jiaying, TANG Lei, YANG Qingjuan, LUO Shixian

Abstract: (111) HTML (0) PDF (0.00 ByteKB) (0)

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With the rapid development of China's economy and the acceleration of urbanization, the quality of urban rail transit systems in large cities is of vital importance to residents' travel experience and the functioning of urban areas, and is directly related to the overall quality of public services. However, there is still relatively little systematic research on the level of urban rail transit services. Based on previous research, this paper combines field surveys and national standard documents to propose 21 evaluation indicators in five dimensions (environmental safety, business and service, spatial design, ecological sustainability, and humanistic care) and conducts a survey of 553 valid questionnaires at Shenzhen and Hong Kong subway stations to study the perceptions of subway users on the importance and satisfaction of service elements. Furthermore, based on the IPA-KANO model, a correlation matrix of latent importance and manifest importance is constructed to determine the priority and importance of service elements in subway stations. The results show that the overall score of the commercial diversity and in-station business situation elements is low, while the overall score of the wayfinding system, in-station rest facilities, and exit design elements is high. Combining the research results, this paper proposes design strategies for subway station facilities and spaces based on service quality improvement for different priority and importance levels, which has positive implications for the construction and continuous optimization design of high-density urban rail transit stations in China.
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Design and analysis of Changping Station through capacity of Northeast Loop Line of Beijing Suburban Railway

chengwen

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The northeast Ring line of Beijing suburban railway is operated by public transport, and the maximum passing capacity of the system is 20 pairs/hour (p/h). Changping Station is the return station of the northeast Ring line and the depot, and the passing capacity of the station should be increased to 20 pairs/hour (p/h). Northeast loop CTCS-2+ATO+automatic turn back control system, in order to improve the ability to meet the requirements of changping station, both changping station yard, signal, optimizing the changping station line, both ends of the throat area and connection with the main line form, combined with the optimization of signal scheme, through traction calculation and scene map drawing, finally make the changping station through 23p/h, not only meet the requirements of the system through the ability, and 13% margin. Through the calculation and analysis of the passing capacity of Changping Station, it is proposed that the number of station lines, the length of the throat area, the signal layout and the operation speed of the station are the main limiting factors affecting the passing capacity of the station, and proposes the solution to improve the passing capacity of the station, so as to provide reference for the relevant design of the suburban railway.
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Research and Application of Embedded Rail Technology in the Renovation of Existing Lines

ZHOU Zhenyu

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To evaluate the application and performance of embedded track systems in the renovation of operational metro lines, this study focuses on a pioneering project implemented on a Guangzhou Metro line. This paper elaborates on the project"s background, distinctive features, construction procedures, and provides solutions to the construction challenges encountered. By comparing the pre- and post-renovation vibration, noise and Track Quality Index (TQI) on track, along with the monitoring of the post-renovation track condition, this study demonstrates the effectiveness of embedded rail track renovation in enhancing the performance of existing lines. The results indicate that this technology can significantly improve the vibration and noise reduction performance of the line while ensuring the continuity and safety of existing line operations.
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Optimization and Application Study of Slide Plate Structure for Urban Rail Transit Turnouts

吕文昊, chenpeng, 段玉振

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The issues of tongue fracture, de-welding between the tabletop and baseplate, and conversion failure occurring on slide plates are major defects in the turnout areas of rail transit systems. The proposed solution of using monolithic cast slide plates, due to complex casting processes, is prone to inclusions and shrinkage porosity, leading to a relatively high scrap rate. Moreover, traditional methods of oiling slide plates for maintenance not only result in significant maintenance workload in switch areas but also cause severe pollution in the track area, eroding the fastener pads and affecting their durability. In response to these problems, optimizations and improvements have been made in key aspects of slide plate design, production, and inspection, including structural design, casting processes, reducing surface friction coefficients, and non-destructive testing.
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Research on the evaluation system and resource allocation method of "Rail-bus-slow travel" triple network integration

Yan Jianxin, WANG Tao

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Regarding the traditional triple network integration evaluation system that only considers the "presence or absence" of rail connection facilities, Ignoring the "good or bad" operation of the facility leads to the inability to evaluate and deal with the connection inconvenience caused by the prominent contradiction between supply and demand and poor travel experience；On the basis of retaining some indicators of 'facility availability', introducing indicators at the levels of "supply-demand matching" and "user experience" for the first time, and the evaluation system of "rail-bus-slow travel" is systematically constructed. And propose key resource allocation methods from the aspects of facility integration, network integration, and operation integration. The research results show that the optimized evaluation system can fully guarantee the convenience, comfort, and safety of track connection, and has a rich theoretical and practical reference value for the systematic improvement of triple network integration in large and medium-sized cities.
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Research on Shield Tunnel Segment Displacement Monitoring Method Based on BOTDA Technology And Diamond-Shaped Layout

Sunxuebing, Chenjian, Lixiaolong, Zhangliren

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Traditional fiber optic sensing deployment methods are predominantly used for one-dimensional or two-dimensional displacement monitoring of tunnel segments, making it difficult to effectively monitor three-dimensional deformation between segment rings. This paper proposes a diamond-shaped layout scheme based on distributed fiber optics, establishing a three-dimensional deformation monitoring method suitable for shield tunnel segments. By analyzing the three-dimensional deformation patterns of tunnel segments, three methods for calculating segment displacement are introduced. To validate the effectiveness of these methods, a simple and operable experimental device simulating three-dimensional deformation of tunnel segments was designed, and indoor tests were conducted. The test results were compared with theoretical calculations, confirming the effectiveness of the proposed diamond-shaped fiber optic layout for segment deformation monitoring, as well as the rationality of the three displacement calculation methods. The results demonstrate that the diamond-shaped distributed fiber optic sensors, combined with the K-value decomposition method, achieve the best monitoring performance for segment displacement. Furthermore, the use of Brillouin Optical Time Domain Analysis (BOTDA) technology enables extensive real-time monitoring of tunnel segment displacement changes.
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Study on unsteady aerodynamic characteristics of urban train passing through the most unfavorable length tunnel

FU Zhichen, LI Tian, LI Yifan, ZHANG Jiye

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In order to explore the aerodynamic characteristics of urban train passing through the most unfavorable length tunnel, the three-dimensional, unsteady, viscous Reynolds time-averaged N-S equation and RNG k-ε two-equation turbulence model were used to carry out the numerical simulation of aerodynamics of 160 km/h urban train passing tunnel. The results verify that the pressure wave and the movement of the train make the flow field and pressure distribution in the tunnel show different regional characteristics. The pressure change of the measuring point of the car body is mainly caused by the pressure wave and the viscosity effect. The pressure change of the measuring point on the tunnel wall is mainly caused by the pressure wave, the extrusion of the air in the tunnel by the train and the low pressure zone around the train. The pressure wave causes the pressure change on the surface of the train to increase the pressure resistance, and the friction resistance increases when the train enters the tunnel. The amplitude of unsteady aerodynamic force increases when the car body enters and leaves the tunnel. The pressure wave has little effect on the amplitude of unsteady aerodynamic force of the first three car bodies, and has a great influence on the amplitude of unsteady aerodynamic force of the last five car bodies.
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Study on the Surface Settlement induced by jacked box Tunnel with shallow overburden

Zheng Peng Cheng, Huang Jia Hao, Liu Wei, Huang Xue Mei, Liu Hao, Zhao Dong Mei

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Addressing the issue of shallow-buried box tunnel machine passing under significant risk sources, this study takes the close-range underpass of the expressway by the underground passage box tunnel machine at Sanyuanqiao Station of Beijing Subway Line 12 as the background. Numerical simulation was used to precisely model the roadbed pavement structure layer of the expressway and simulate the entire construction process of the underpass. The ground surface deformation patterns caused by the box tunnel machine under the expressway were analyzed, and a parameter sensitivity analysis was conducted on construction parameters such as the support pressure at the pipe head, ground loss, and grouting pressure during the pipe jacking construction. Finally, video monitoring was used to monitor and verify the settlement of the expressway. The results show that the ground surface deformation caused by shallow-buried box tunnel machine can be summarized into three stages: slight surface uplift, rapid surface settlement, and final settlement stabilization. Changes in ground loss and grouting pressure are the most sensitive to settlement variation. The established numerical model can reflect the basic patterns of surface deformation caused by pipe jacking construction, as indicated by on-site video monitoring data. The maximum settlement of the highway surface meets the control standard of ≤15mm.
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Optimization Study of Flexible Train Composition and Full-length and Short-turn Routings Based on NSGA-II

fujiale, 文静, 徐纪康, 付雅婷, 周艳丽, 施宇豪

Abstract: (607) HTML (0) PDF (0.00 ByteKB) (0)

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In response to the diversified and uneven demand for passenger travel, with the goal of improving service levels, this paper proposes an operational mode for urban rail transit, which involves online Flexible Train Composition and Full-length and Short-turn Routings, and integrates NSGA-II algorithm to optimize the operational scheme. Firstly, the paper analyzes the turnaround scenarios of trains under flexible composition conditions and determines the relationship between turnaround time and departure intervals. Secondly, using passenger travel costs and train operating kilometers as objective functions, a mathematical model for the operational mode of urban rail transit with online Flexible Train Composition and Full-length and Short-turn Routings is designed based on the NSGA-II algorithm. Finally, a case study is conducted to verify the feasibility and effectiveness of the algorithm for a specific rail transit line. The results show that compared to single routing, Full-length and Short-turn Routings, and mixed operation modes with multiple compositions, the proposed operational mode reduces vehicle operating kilometers by 42.68%, 22.81%, and 15.98% respectively, reduces vehicle utilization by 35%, 23.53%, and 16.13% respectively, and reduces the maximum load factor from 161.71%, 123.54%, and 135.49% to 119.68%. This operational mode effectively reduces vehicle operating kilometers and utilization while ensuring service levels and improving the balance of line load factor, thereby bringing greater benefits and improvements to urban rail transit systems.
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Estimation method of urban rail transit passenger route choice based on multi-source data

Zhu Guo, Zhang Lanlan, Liu Jiajun, Yang Haofan, Yin Lichao, Zhang Ning, Zhang Hengwen

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The network operation of urban rail transit has introduced diversity in passenger route choices. Given that it is difficult to accurately determine passengers' network route choices based on existing Automatic Fare Collection (AFC) transaction data and probabilistic inference methods, thus affecting tasks such as rail transit network passenger flow allocation and ticket clearing, this paper utilizes network station information to construct an urban rail topology network. It searches for feasible path sets for OD pairs and uses multi-source data, including AFC transaction data, mobile signaling data, and train schedule data, to build a nonlinear optimization model to infer passengers' travel route choices. Experiments based on the Nanjing Metro network show that the model is effective and robust. This study can provide guidance for urban rail transit operations and ticket clearing.
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Study of Deformation Control Measures for Concealed Underground Tunnels in Loess Areas Through Existing Stations in Close Proximity

Zhen Fulong

Abstract: (102) HTML (0) PDF (0.00 ByteKB) (0)

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Aiming at the problem of excessive settlement of the station caused by the new tunnel close to the existing station, relying on the project of Xi 'an Metro Line 8 close to the Convention and Exhibition Center Station of Line 2, the numerical simulation and on-site monitoring are used to analyze the control effect of various control measures on the deformation of the existing station during the construction of the underpass. The recommended values of construction parameters of the tunnel in the loess area are given. The results show that : (1) The construction method and excavation footage have obvious effect on the deformation control of the station when it is close to the underpass. After the construction method is adjusted from the upper and lower step method to the on-site CRD method, the maximum settlement of the station is reduced by 50%. After the excavation footage is adjusted from 1.5 m to 0.5 m, the maximum settlement of the station is reduced by 30%. (2) The staggered distance between the upper and lower pilot tunnels and the erection of temporary steel support have a weak effect on the deformation control of the station, which can be appropriately adjusted according to the engineering geology and on-site monitoring. (3) Based on the project, the construction scheme of on-site CRD method + 0.5m excavation footage + 5m single-side cavern upper and lower guide hole staggered distance + 5m spacing temporary steel support is adopted. The on-site monitoring shows that the maximum settlement of the station side wall is ?3.76mm, which is basically consistent with the numerical simulation. The maximum settlement of the track bed and the track is ?2.55mm and ?2.51mm respectively, which meets the requirements of the station deformation control standard.
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Gather-distributing Characteristics of Passengers between Facilities in Subway Station

YUAN Bohui

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Abstract:

Passenger gather-distributing is determined by dimension of facilities, walking behavior of passenger, passenger density and path choice preference, which is basis of quantifying the distribution of passengers in subway station. Firstly, based on the density of passenger, passenger state-space was constructed and its steady-state probability was presented. Secondly, state-transfer model of passengers was constructed, and expression of passenger blocking and unblocking probability was depicted. Finally, in order to illustrate the measurement is valid, the changing of passenger distribution in station was verified. The experimental results showed that when passenger density exceeds the free-flow density, because the actual passenger flow exceeds a certain threshold, traffic congestion occurs in small-capacity facilities. And the actual passenger gather-distribution features are not only related to the capacity of a single walking facility, but also to the bottlenecks of the network.
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Study on piston wind characteristics of moving trains in subway tunnels

LIU Jijian, MENG Xin, LAN Huifeng, WANG Qianying, HE Yuesong, ZHANG Fengjun, ZHANG Ling, JIANG Wenwen

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Piston wind will be formed in the process of subway train running in the tunnel, which will have a certain influence on the flow field in the tunnel. It is of great significance to study the characteristics of piston wind for rational utilization of piston wind. Based on Bernoulli equation of unsteady flow, a lumped parameter theoretical model of piston wind in subway tunnel is established, and the characteristics of unsteady piston wind are analyzed. In order to verify the accuracy of the theoretical model, a reduced size model test bench of 1:16 was established, and the piston wind speed was tested experimentally. The comparison between the model value and the measured value shows that the Pearson correlation coefficient is higher than 0.98, and the average error is lower than 13%, which verifies the correlation and accuracy of the theoretical model. By using the lumped parameter theory model, the influence of different factors on the piston wind in subway tunnel is explored, and the grey correlation degree is analyzed. The results show that the congestion ratio is the biggest factor affecting the ventilation effect of the tunnel piston, followed by the train length and train speed, and the tunnel length is the least. Based on this, a fitting formula for the ventilation effect of the piston in common subway tunnels in China is proposed.
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Study on Comprehensive Inspection Mode of Beijing Subway Interval Facilities

YU Lin, LI Yujie, YE Libin, ZHANG Jun, YANG Shuo, CUI Guangyan

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To improve the inspection level of Beijing Subway interval facilities, and achieve the goal of cost reduction and efficiency increase, the inspection basis of interval facilities was clarified based on the national standard, industry method, local standard and enterprise standard. The automatic inspection equipment and way of inspection of Beijing Mass Transit Railway Operation Corp. Ltd. were discussed. The functional parameters, advantages and disadvantages of typical comprehensive inspection equipment were compared and analyzed. The comprehensive inspection mode of Beijing Subway interval facilities was presented. The results indicate that the enterprise standard can cover the inspection contents and inspection cycles in the national standard, industry method and local standard. The comprehensive detection vehicle is suitable for dynamic inspection, while the comprehensive detection car is suitable for static inspection, both of which are far superior to the handheld equipment. The on-board detection equipment is mainly used for routine inspection. The comprehensive detection vehicle and the comprehensive detection cars combined with the existing professional detection equipment are mainly used for scheduled inspection. The fixed monitoring system and the handheld equipment are mainly used for special inspection. The comprehensive inspection should be implemented by leasing service in the short term, and by purchasing equipment in the long term. This study can serve as a reference for promoting the intelligent operation and maintenance of urban rail transit infrastructure.
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Design and Analysis of Platform Screen Door Technical Solutions Adapting to Multiple Vehicle Models under the Background of "Four Networks Integration"

wangyujue, 马松, 刘潇洋

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Addressing the compatibility issues of platform screen door (PSD) systems across different lines and vehicle types within the context of "four-network integration," this study innovatively proposes a design scheme for an adaptive PSD system, encompassing comprehensive solutions such as improving mechanical structures, optimizing control system algorithms, enhancing intelligence levels, and bolstering gap detection system capabilities. These solutions aim to elevate the flexibility and safety of PSD systems, thereby better accommodating the needs of diverse vehicle types and operational modes. By facilitating the adaptability to multiple vehicle types, they contribute to reducing station sizes and lowering construction costs for urban rail transit. This research provides valuable reference and insights for the upgrading of PSD systems under the backdrop of "four-network integration" in urban rail transit. By optimizing the design and functionality of PSD systems, it can effectively mitigate the impact of multiple vehicle types on PSD systems, further facilitating the smooth implementation of "four-network integration."
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The influence of PCA scale on the correlation model between urban built environment and rail passenger flow

Yuan Lu, Jin Zhao, Yifeng Yao

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Objective: With the rapid development of urban rail transit, the subway, as an important public transportation, provides an efficient large-scale travel option. Previous studies generally believe that the built environment around subway stations affects the passenger flow, but the size of PCA (Pedestrian Catchment Area) has not yet been unified. The purpose of this study was to verify whether the size of PCA affects the outcome value of the correlation study between metro ridership and the built environment. Methods: Taking 25 stations of Nanning Metro Line 1 as an example, five indicators were selected as independent variables, including residential population, jobs and commercial facilities, and the actual passenger volume of the stations was used as the dependent variables. The OLS regression model was used to compare the results of model fitting and influencing factor analysis under different PCA radius variables. Results: There were differences in the research results of the relationship between passenger flow and built environment in the data collection of PCA in subway stations within different catchment areas. For Nanning, the radius of the PCA is 600m, and the fitting of the correlation model between subway passenger flow and built environment is better than that of 300m and 900m. Conclusion: The scope of PCA will lead to inconsistency in the results of the study on the association between subway passenger flow and the built environment. In the future, it is necessary to conduct model analysis for different PCA radii and determine the appropriate PCA scale according to the fitting effect to improve the accuracy of the research.
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Renewal Potentials of Rail Transit Station Area in Inventory Areas of Tianjin——An Analysis by "Node-Place-Quality" Rubik's Cube State Model

郭源园

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As a catalyst for urban renewal, the construction of urban rail transit provides important opportunities for improving the quality of urban space of transit station area in the downtown, and also brings new impetus to the inventory development. By incorporating the "Quality" dimension into the traditional "Node-Place" model to indicate the perception of spatial environment, this paper constructs the “Node-Place-Quality” Rubik's Cube state model, which aims to assess the renewal potentials of transit station areas in the downtown. By taking the central area of Tianjin as case study, the modeling results show that the proportion of dependent and imbalanced types of transit station area is as high as 35.49% and 38.71%, respectively, while balanced and coordinated types account for 22.58% and 3.22%, respectively; The transit station areas with high renewal potential are concentrated in the edge of the Inner Ring of Tianjin, and the renewal potential of transit station under construction is also relatively high, while the transit station areas with low renewal potential are agglomerated in the central business district (CBD). These findings provide theoretical support and policy insights for the urban renewal in the transit station area in the metropolitan`s downtown.
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Research on the design method of FAO failure handling plan based on FMEA-EWM

Wen Qian, Wang Yu, Zhang Kun, Chen Jiadi, Niu Ru

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The fully automatic operation (FAO) system has become the mainstream of urban rail transit in China. Considering factors such as safety and timeliness of emergency response, at present, FAO lines in China still operate in a staffed manner, failing to give full play to the "fully automatic" advantage. To address the concerns of operation units and improve the efficiency of emergency response for equipment failures, this paper proposes an emergency plan framework related to FAO line directed by key equipment based on extensive survey on the current emergency plans of fully automatic operation lines in multiple cities. Aiming at the problems of insufficient completeness and poor operability of current emergency plans, a design method of emergency plans for fault handling that integrates failure mode analysis and entropy weight method is proposed. Considering five factors such as the severity, occurrence probability, scope of influence, difficulty of isolation, and difficulty of operation restoration, objectively calculate the comprehensive fault impact index, combined with system design information and operation log data. Based on this impact index, operators can determine the fault handling strategy and design the emergency plans. Finally, taking the axle counter equipment as an example, the equipment fault mode is classified and an emergency plan is designed targeted with 85 months of fault log data of a certain line. The results show that the completeness and operability of the failure handling emergency plan have been effectively improved.
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Thermal Modeling and Online Condition Monitoring for the Air Cooling System of Power Converters for Urben Rail Transit

Zhou Qian, Chen Jie

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During the long-term operation of the cooling system, the impurities and dust in the ambient will go inside heatsink channels with cooling air, affecting the thermal dissipation efficiency and significantly decreasing the reliability of power converter. Existing offline condition monitoring methods of the cooling system have the problems of low accuracy and high-cost, a real-time online monitoring method of the thermal dissipation state is proposed based on the thermal modeling of cooling system. In this paper, a real-time online cooling system thermal state monitoring method is proposed. The method utilizes Gauss-Newton iterative method to identify the steady state thermal resistance, and then realizes online monitoring of cooling system heat dissipation status with the steady state thermal resistance as the characteristic parameter. Finally, the established online monitoring method is verified through simulation and experiment, and the results show that the proposed cooling system online state monitoring method can accurately monitor the cooling system operation state and provide support for the intelligent operation and maintenance of the converter.
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Characteristics Analysis of a Supercapacitor-Battery Hybrid Scheme for Regenerative Braking Energy Utilization in Urban Rail Transit

LI Lu, ZHAO Yajie, LIN Fei, YANG Zhongping

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This paper focuses on the utilization of regenerative braking energy in urban rail transit, comparing key parameters such as working principles, power density, and energy density of supercapacitors, lithium titanate batteries, and flywheels. The paper analyzes the characteristics of a hybrid energy storage system composed of supercapacitors and lithium titanate batteries. Simulation results demonstrate that the hybrid energy storage system, combining supercapacitors and lithium titanate batteries, offers significant advantages over systems solely based on supercapacitors or batteries. These advantages are particularly evident in scenarios such as regenerative braking energy recovery, enhancing substation power supply capabilities, and supporting emergency traction of trains. The study highlights the potential of hybrid energy storage systems in optimizing the utilization of regenerative energy in urban rail transit.
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Research on the Construction Plan of Integrated Operation and Dispatching System for Monorail Transit

LIU Tao, YANG Chao, CHEN Guang

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This article analyzes and studies the problems of relatively independent specialties, a large number of various workstation terminals, high usage, management, and maintenance costs in the current monorail transportation operation and dispatch system. In the event of faults or accidents, the data between subsystems is not interconnected, and coordination and command are difficult. The analysis and research are conducted from the aspects of data control, various subsystem business implementation, and comprehensive requirements for operation and maintenance. This paper elaborates on the architecture scheme of a deeply integrated monorail comprehensive operation and scheduling system based on a unified software/hardware platform and human-machine interface for various professional subsystems, and analyzes different application directions such as upgrading and renovation of existing lines, construction of new lines, and network-level integration. This article addresses the needs of data control and comprehensive intelligent operation and maintenance. It integrates and designs the architecture of center, station, and depot/parking lot system equipment, integrates or interfaces various subsystems, and monitors and controls various professional system equipment on a unified platform. Through analysis, the adoption of a single track system with comprehensive operation scheduling greatly improves the degree of system integration, simplifies job positions, and effectively reduces construction and operation costs. The comprehensive operation and scheduling system can achieve the interconnection and sharing of various professional resources. In the event of emergencies or equipment failures, it can provide users with complete and rich information support within a unified comprehensive platform. Through intelligent linkage and other automatic control technology means, it can significantly improve operational efficiency. Integrated operation and dispatching system solution conforms to the development direction of integrated, simplified and simplified monorail transportation system, and will be the development trend of China's monorail transportation operation and control system in the future.
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Research on Model Selection of Medium and Low Carrying-capacityUrban Rail Transit Based on CRITIC-TOPSIS Model

Li Xuesong, Chao Yuhong, XU Chuangchuang, WEI Changhai, LV Yukai

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Guided by the need to address the shortcomings of subjective selection and the mismatch between capacity and demand in the selection of existing medium and low capacity urban rail transit standards, the standardized and procedural decision-making system for standard selection has been developed. Firstly, the 4 criterion and 16 index evaluation system has been established, considering constraints such as peak hour passenger flow, minimum transport capacity reserve, and the number of train operations. A multi-objective optimization model has been constructed to determine the set of candidate rail transit systems. Besides, the CRITIC-TOPSIS algorithm has been constructed to determine the weight coefficient values of each indicator and the optimal solution distance, thereby determining the optimal track system. Finally, using the S-line as the background for example verification, 5 alternative track systems were evaluated through a quantitative model. The CRITIC and TOPSIS algorithms were implemented using Python software. The decision value of rail transportation system is in order of self-guided monorail, cross-seat monorail, light rail, guideway rubber wheel and low and medium-speed magnetic levitation, so that the optimal rail system of line S is self-guided monorail. Analyzing the standardized scoring matrix and index weight values of each type of rail system, the research results show that the model and algorithm proposed in this paper can effectively solve the problem of low and medium-capacity rail transportation system selection.
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Experiment study on mechanical performance of steel fiber reinforced concrete segment with oblique bolt joint

YANG Weiwei, JIA Yonggang, WU Fan, LU Weidong, Cui Hongzhi, Chen Xiangsheng

Abstract: (114) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

To solve the problem of unclear mechanical properties and damage mechanism of steel fiber reinforced concrete segment of shield TBM with oblique bolt joint. In this paper, a segment structure with an external diameter of 6.2 m and a thickness of 350 mm was used as a prototype to carry out bending performance tests of steel fiber concrete segment with oblique bolted joints under 4 horizontal axial force conditions. The deformation characteristics and flexural performance of the segment joints under different axial force levels were analyzed, as well as the failure process and mechanical properties under failure conditions were investigated. The results show that the higher the axial force on the segment joints, the higher the joint stiffness, causing larger bending moments required for joint opening. That is, it can actively increase the joint axial force by increasing the bolt preload or applying annular prestressing to improve the joint stiffness. The compression of the sealing gasket under joint axial force causes stress concentrations in the sealing groove, and it is necessary to select a suitable sealing gasket or optimize the sealing groove structure in the design. It is shown that enhancing the compressive strength of the top concrete and reducing the insertion angle of the oblique bolt are favorable to the improvement of the joint bearing capacity. The research results can be used to guide the segment joint design.
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Experimental Study on Rail Corrugation Treatment for Vibration Reduction Tracks in Beijing Subway

CUI Rixin, SHI Yi, LI Yulu, WANG Jin, LI Zhonghua

Abstract: (93) HTML (0) PDF (0.00 ByteKB) (0)

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To verify the effects of rail damping devices in rail corrugation treatment for vibration reduction tracks, rail damping devices were added to the ladder-type sleeper track and the steel-spring floating slab track respectively in this paper. Vibration and trackside noise characteristics of the two vibration reduction tracks were reported, and the developments of rail corrugation were tracked. The results show that the rail damping devices installed on the ladder-type sleeper track can receive positive effects of vibration and noise reduction in a wide band range, which can reduce rail vibration and trackside noise by 9.7dB and 11dB(A), respectively. The rail damping devices installed on the steel-spring floating slab track can reduce rail vibration and trackside noise by 8.3dB and 3dB(A) in its working frequency range, respectively. The long-term tracking tests show that installation of rail damping devices can at least double the development rates of rail corrugation on vibration reduction tracks.
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Spatiotemporal Heterogeneity and Nonlinear Analysis of Factors Affecting Rail Transit Ridership—A Case Study on Tianjin

ZHANG Pengyu, LI Zhengzhong, ZHANG Xiran, WANG Yuqin

Abstract: (132) HTML (0) PDF (0.00 ByteKB) (0)

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To explore the impact mechanism of population socio-economic, land use, station characteristics, and other transportation attributes on rail transit passenger flow, based on multi-source data such as LandScan population grid, points of interest (POI), and automatic fare collection system (AFC), the spatiotemporal geographic weighted regression, gradient boosting regression tree, Shapley addition explanatory (GTWR-GBRT-SHAP) model was used to analyze the spatiotemporal heterogeneity and nonlinear effects of the above factors on passenger flow. A case study was conducted using data from Tianjin rail transit network, and the results showed that the mixed model has good fitting goodness in capturing the spatiotemporal heterogeneity and nonlinearity of influencing factors and passenger flow. Factors such as population density, office type land, shopping and leisure land, and betweenness have significant spatiotemporal differences in impact of passenger flow. Factors such as residential type land, transportation facility land, land use entropy, and betweenness have significant complex non-linear and threshold relationships with passenger flow. The above results provide strategic references and theoretical support for optimizing public transportation oriented urban development (TOD) planning and improving the efficiency of rail transit passenger flow.
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Identification of Redundancy Critical Stations in Rail Transit Networks Based on the Shortest Time Path

WU Peng, LI Dewei, DAI Zhicheng

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Redundancy is a crucial attribute of resilience. To address the neglect of time redundancy of critical station identification in rail transit networks, firstly, A time-weighted rail transit network model based on Space L and multi-line coupling is proposed, considering the transfer time between stations. Secondly, an attack mode of node deletion is used to simulate station interruption scenarios, and a station redundancy index, network redundancy index, and redundancy evaluation model based on the shortest travel time change are proposed. Finally, Chongqing rail transit network in 2024 is taken as a case study, and the differences between the redundancy index and betweenness evaluation results are compared. The results show that the average station redundancy index is 0.7998, with 3.87% of stations having a redundancy index K-means clustering center of 0.2788, indicating poorer redundancy for some stations which are more critical. Redundancy critical stations are mainly located near the network ring in longer lines extending outward, while betweenness critical stations are mainly interchange stations where multiple lines intersect, showing significant differences between the two groups of critical stations. Compared to interruptions at betweenness critical stations, interruptions at redundancy critical stations have a more significant and targeted impact on network performance, thus verifying the effectiveness of the redundancy critical station identification method. The proposed method can provide references for resilience optimization of urban rail transit networks.
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Research on Passenger Feature Identification in Surveillance Videos of Urban Rail Stations Based on Skeleton Movements Pattern Recognition

GUAN Yang, JIA Limin, TAO Sihan, DOU Fei

Abstract: (96) HTML (0) PDF (0.00 ByteKB) (0)

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In the field of urban rail transit, the demand for safe operations and the provision of excellent services is increasingly growing. Video surveillance systems face new challenges in identifying passenger abnormal behaviors such as falling, fainting, and fighting. Traditional monitoring analysis methods have poor performance in the application of video surveillance image abnormal behavior recognition, with high false-negative rates and complex parameter adjustments, making them difficult to efficiently apply to actual urban rail station monitoring scenarios. Therefore, this paper proposes a human posture feature recognition framework based on skeleton pattern recognition, introducing a posture estimation technology based on human skeleton. The Alpha Pose model is used to accurately estimate the posture of passengers, and combined with the Spatial Temporal Graph Convolutional Networks model, it achieves abnormal behavior recognition in the monitoring scenario of urban rail stations. By achieving 72.3 mAP on the COCO dataset and 82.1 mAP on the MPII dataset, the performance is improved by up to 17% compared to the OpenPose model, verifying the effectiveness and practicality of the model. The results show that the method proposed in this paper not only improves the recognition speed of passenger behavior but also has the ability to adapt to complex scenarios, providing a new technical solution for urban rail safety monitoring.
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Optimization of Combined Support Systems for Existing Subway Ancillary Structures Affected by Adjacent Excavation

TAO Chang, PENG Liyun, LIU Bingke, CHEN Hanyu

Abstract: (100) HTML (0) PDF (0.00 ByteKB) (0)

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Aiming to solve the difficulties posed by the difficulty in constructing supporting structures for deep excavations near obstacles on one side, a combined support system of retaining piles, tensioned anchor rods, and inclined anchor cables with grouting was put forward. The study utilized Midas software for modeling, and single-factor optimization analysis schemes were designed from five aspects: grouting area strength, spacing and diameter of tensioned anchor rods, number and length of segments for inclined tensioned anchor cables. The rationality of this scheme was validated through engineering examples. The results show that the simulated trends of horizontal and vertical displacements of slope protection pile tops match the monitoring results. The vertical displacement exhibits a parabolic trend,and the horizontal displacement exhibits an arch shape. The maximum horizontal displacement of pile tops decreases as the spacing of tensioned anchor rods decreases, and increases as the diameter of tensioned anchor rods, grouting area strength, and the number and length of segments of inclined tensioned anchor cables decrease. During construction, the deformation of subway ancillary structures is well-controlled and significantly less than the pile cap displacement of the adjacent deep excavation. Top settlement shows a fluctuating upward trend, while deep horizontal displacement has a middle-high, end-low pattern at different excavation stages. As excavation depth increases, the maximum horizontal deformation of the subway structures shifts downward along the shaft wall.
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Parameter optimization of locking pipe curtain based on combination weighting TOPSIS-BPNN-GA method

dujiajun, Yan Qixiang

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Relying on a subway station entrance and exit channel pipe jacking project, combined with the on-site monitoring data for jacking parameter inversion, the refined pipe curtain-corridor-strata pipeline corridor jacking finite element model considering the locking joints was established.The deformation of strata with and without pipe curtain is analyzed comparatively, and the necessity of pipe curtain is verified. Then, the effects of pipe diameter, pipe spacing and pipe thickness on surface settlement, pipe curtain cost and joint gap were systematically investigated through comprehensive tests, and a comprehensive evaluation system of TOPSIS was established to evaluate the adaptability of the pipe curtain with game combination assignment.Subsequently, BPNN was used to fit the mapping relationship between the pipe curtain parameters and the adaptability, and finally the genetic algorithm was used to search for the optimal parameter combinations.The study shows that the parameter that has the greatest influence on the adaptability of the pipe curtain is the diameter of the steel pipe, followed by the clear distance of the steel pipe, and finally the thickness of the steel pipe.Considering the safety, water resistance and economy, the recommended design parameters of the locking pipe curtain are the steel pipe diameter of 990 mm, the steel pipe thickness of 20 mm, and the steel pipe clearance of 160 mm.
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Study on travel behavior of the river-valley type city considering space perception based on SEM-Logit

FAN Mengxing, QI Jinping, ZHENG Xiangdong, SHANG Hongtai, Kan Jiayun

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In order to explore the impact of travelers' subjective spatial perception on travel behavior in the context of special urban terrain, this paper takes Lanzhou, a typical river-valley type city, as an example. It establishes an integrated model of SEM-Logit and explores the impact of spatial perception of the river-valley type city travelers on rail transit travel mode choice based on questionnaire data. The results show that :① Compared with the Logit model without considering travel space perception, the goodness of fit of the Logit model considering travel space perception by SEM is increased by 0.234, and the prediction accuracy is increased by 7.75%. ② The spatial perception of travelers in river-valley type cities has a significant positive impact on the choice of rail transit travel intention and behavior.③ The space perception of travelers in the river valley-type city from five aspects, including the unnecessary detour, rivers in the river valley-type city, wasp waist blockage, the convenience of inter-group travel and the degree of being affected by road slope, will significantly influence travelers in the river valley-type city to choose rail transit, and the degree of influence will decrease in turn.
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Research on summer thermal environment and thermal comfort of Wuhan elevated subway station

CHEN Xiaowei, ZHANG Chi, YANG Caihong, HE Yu, WANG Bo

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To explore the thermal environment and thermal comfort of elevated subway stations in Wuhan,this study aimed to determine the thermal comfort range for passengers and understand the influence of elevated station architectural forms on passenger thermal comfort.The study used a combined method of instrument measurement and subjective questionnaire to investigate five typical elevated stations during typical summer days.Measurement results indicate that most of the time,stations cannot meet the requirements of GB 50157-2013"Code for design of metro".Air temperature in the station is excessively high,the relative humidity generally satisfying criteria,most stations have low air air velocity.The questionnaire results demonstrate a significant correlation between the station's forms and passengers' thermal comfort,passengers prefer open platforms in summer.By linear fitting of SET*(Standard Effective Temperature) and MTS(Mean Thermal Sensation) for two stations, obtain the passenger's thermal sensation range.The PTS(Predicted Thermal Sensation) curve consistently exceeds the SET*-MTS curve,indicating that passengers' summer heat adaptation exceeds expectations.Proposed measures for shading, ventilation, and thermal environment improvement.This provides theoretical references for improving thermal comfort and promoting green transformation in elevated subway stations in regions with hot summers and cold winter zone.
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Research on the influence mechanism of passenger flow in urban rail transit network based on panel data analysis

SHI Zhuangbin, LIU Xiaoqing, Qian qian, HE Mingwei, LIU Yang

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The rapid expansion of urban rail transit significantly promotes the connectivity and accessibility of urban networks. The application of complex network theory in transportation network is becoming more and more extensive, but the influence of urban rail transit network structure on passenger flow changes remains to be further studied. Based on the panel data of urban rail transit from 2012 to 2020, this paper uses the time fixed effect model to construct the influencing factor model of passenger flow change. By constructing the time fixed effect model and comparing the models, this paper tries to explore the influence of urban rail transit network topology and its coupling relationship with urban layout on passenger flow change. The results show that with the development of urban rail transit network, the complexity of traffic network structure is getting higher and higher, and the number of transfer hub stations is increasing, which plays an important role in network connection. The change of topological variables of urban rail transit network has a significant impact on the increase of passenger flow. The densification of network distribution and regional hub are helpful to improve transfer connection and attract more passenger flow. The coupling coordination degree has a significant impact on the change of passenger flow. The coupling relationship between population distribution and line layout needs to be considered in the planning of rail network according to local conditions. Finally, relevant policy suggestions are put forward from the aspect of rail transit network construction planning, which can provide theoretical basis for the relevant policy formulation of urban rail transit construction planning.
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Research on Centralized Rectification Scheme for DC Lighting System in Metro Station

liuyajie

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The existing decentralized rectification scheme for direct current (DC) lighting systems in metro stations has shortcomings such as lower system power supply reliability and system power supply efficiency, excessive cable cost, large distribution cable losses, and inconvenience for unified maintenance of equipment and unified management of power quality. In order to solve the above problems, we proposed a centralized rectification scheme for the DC lighting system of metro stations.This paper introduced the system architecture, current situation and shortcomings of the decentralized rectification scheme of the DC lighting system in the metro station. This paper introduced the system architecture of the centralized rectification scheme for the DC lighting system in metro stations, the DC power supply configuration, the system key configuration ,and the scope of changes the solution will make to the existing system. Using specific engineering application data, make a detailed comparison of the system loss, system cost, System harmonic content ,and system operation reliability of the two rectification schemes.The result shows that the centralized rectification scheme has feeder cable usage than the decentralized rectification scheme, and its system cost is more advantageous. The centralized rectification scheme has lower cable losses than the decentralized rectification scheme. The system power efficiency of centralized rectification scheme is higher than that of decentralized rectification scheme. The system harmonic content of centralized rectification scheme is lower. The power module in the centralized rectification scheme will have better operating conditions and its system stability will be better. The centralized rectification solution is more suitable for DC lighting systems in metro stations.
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Evaluation and promotion strategy of the TOD of Xi 'an rail transit station

wangwen

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Aiming at the poor integrated development effect of TOD station and the problems of mismatch between rail station planning and the renewal of surrounding cities, this paper based on the classic NP (Node-Place) model and the introduction of NPR (Node-place-Ridership) model of passenger flow, taking Xi 'an Metro Line 3 as an example and relying on spatio-temporal big data, The passenger flow data within 24 hours in 6 consecutive months were selected to calculate the basic indicators of 26 stations, and the stations were divided into 6 categories: place advance & low passenger flow, deficiency & low passenger flow, matching type & medium and low passenger flow, node advance & medium and high passenger flow, node advance & medium and low passenger flow, and saturated node advance & high passenger flow. This paper aims to combine the development characteristics and needs of Xi 'an, and accurately match the optimization strategy of the site through theoretical analysis.Research shows that the overall node value of Xi 'an Metro Line 3 is high and the value of this place is low ,and each type of station has distinct characteristics.This paper identifies the same characteristics of 6 types of stations, gives 3 types of process transformation measures, and gives differentiated improvement strategies for different areas of Xi 'an Metro, in order to provide scientific and systematic guidance for the planning, design and management of Xi 'an urban rail transit stations, so that the stations can better integrate into urban life and promote urban renewal and sustainable development.
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Analysis of Commuting and Job-Housing Spatial Characteristics Based on Light Rail Corridors: A Case Study of Addis Ababa

Li Jingwei, Ji Qianyun, Feven Tesfay Belay

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To address the growing population and transportation demands, Addis Ababa constructed a light rail transit system in 2015. This study aims to analyze the impact of the light rail system on residents' commuting and the spatial distribution of employment and residential areas. Based on official city maps, resident questionnaires, and interview data, a multiple linear regression model was employed to analyze the influence of different commuting methods on commuting time. The findings indicate that the light rail system has a limited effect on improving residents' commuting efficiency. Further GIS spatial analysis reveals that the overall distribution of residential and employment areas in the city is uneven, with suburban residential density being more than five times that of urban areas. The analysis results reflect that the failure to coordinate land use with the development of the light rail corridor is a primary reason for the low commuting efficiency. The conclusions advance the understanding of the adaptability and implementation strategies of the Transit-Oriented Development (TOD) model in countries with low-density sprawl and relatively underdeveloped economies.
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The Technology of Replacing Bridge Bearings Without Jacking Up the Beams Based on Bidirectional Adjustable Bearings

zhangxue, xuliang

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In response to the maintenance needs of bridge bearing defects, existing bearing replacement methods all require jacking up the bridge to complete the bearing replacement, significantly impacting bridge structural safety and traffic operations. This study designs and manufactures a "low-melting-point alloy bidirectional height-adjustable force-measuring bridge bearing," leveraging its bidirectional height-adjustable characteristics to develop a technology for replacing bridge bearings without jacking up the bridge. Against the backdrop of practical engineering applications, a comparison is made between the "bridge bearing replacement technology without jacking up the beams" and the existing "bridge bearing replacement technology with jacking up the beams." Utilizing this technology, bridge bearing replacement can be achieved without jacking up the superstructure, effectively avoiding stress changes in the bridge structure caused by jacking and enhancing maintenance efficiency and safety. Additionally, this technology is easy to operate, has minimal impact on traffic operations, and possesses broad applicability and promotional value.
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Research on BIM-based Digitalization Method for Existing Rail Transit Projects

HUANG Yige, WANG Bo, LI Guang, LAI Huahui, ZHONG Yuqi, HUANG Hongda

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Abstract:

Considering the problems of the difficult data collection, non-standard models, and inaccurate data in the digitalization of existing buildings, the BIM-based digitalization method for existing rail transit projects was studied and proposed, according to the characteristics of rail transit projects. First, based on data requirements of the operation and maintenance management, an overall framework for BIM digitalization and scenario applications in existing rail transit projects was developed. Second, the technical guideline for BIM modeling and delivery was studied and established, and a BIM component standard library was developed to standardize the creation of BIM models of existing rail transit projects. Third, according to the on-site data collection situation, different methods were adopted to create BIM models of existing rail transit projects. When the drawings were complete, models could be created based on the drawings; When some drawings were missing, the BIM models creation method based on the on-site images and point cloud data was studied through component feature recognition and matching component units in the BIM component standard library. Finally, to ensure the quality of BIM models, the compliance checking tool which was embedded BIM standard specifications was developed to check automatically BIM models. Additionally, the on-site inspection was conducted on various professional BIM models. The BIM construction of existing operating lines in Shenzhen Metro is being carried out, accumulating BIM-based digital assets, which provides reference for the BIM construction of existing operating lines in other cities.
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Interconnection 2.0：Research on Synergy Mode of Rail Transit and Urban Space based on Multi-level Network Efficiency

zhujinjin, xiahaishan, liuxiaotong, XU Ran

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China's urbanization has entered the stage of urban agglomeration construction and high-quality development, and the role of rail transit network in supporting the spatial development of urban has become increasingly important. However, as rail transit interconnected，the urban space enters a higher network level, and how to improve the spatial efficiency of the metropolitan area has become a research concern. This article analyzes the research characteristics and shortage of synergy mode between interconnecting rail transit network and urban space through bibliometric methods. Introducing the idea of network and mobility into theoretical research, further taking efficiency as the starting point, analyzing the key to synergistic development of network structure and function between rail transit and urban space, then the Interconnection 2.0 Mode of synergy development between rail transit and urban space is proposed, and the synergy relationship is strengthened from three aspects:network structure connectivity, network nodes and element flow. Combined with case analysis, this paper prospects the future development direction of interconnection at a higher stage in China. Theoretically, we focus on the study of network hierarchy and nodality as well as the interaction between flows，and in practice improves the network connectivity and coupling of multi-level rail transit hubs.
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Research and Application of Grounding Leakage Protection Scheme for Suspension Monorail Transit DC System

yin shuang

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[Objective] Through the analysis of the suspended monorail transit power supply system, it is necessary to set up DC system grounding leakage protection to ensure the safety of equipment and personnel under various working conditions.[Method] Although conventional voltage type grounding leakage protection devices can achieve protection functions, they cannot achieve selective tripping and expand the fault range. According to Kirchhoff's current law, an innovative section current type grounding leakage protection scheme is proposed. Through the application of inverse time current curve and differential current components, accurate and rapid positioning of fault sections is achieved, and corresponding sections are prioritized for tripping and cutting off faults, resulting in a qualitative improvement in system selectivity.[Resule&Conclusion] Based on the analysis of the protection object, protection range, protection type, and action time limit of 64D protection and frame current protection, it is concluded that the two types of protection do not conflict and can be used simultaneously. Through practical engineering applications, each protection function is sensitive and reliable. By calculating the key parameters of 64D protection, a protection scheme and system setting value are proposed for practical engineering applications, optimizing the selectivity of the protection system, effectively reducing the range of faults, and ensuring safe operation.
1
wu

Jiang Yun Ping, miao ya jun, li jian jian, 辛华, 甘建文

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Abstract:

wu
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Analysis of Size Effect of Deep Circular Working Shaft Excavation for Intercity Railway Construction

Han Weijie, yangguofu, lixinhai, 曹成勇

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In response to the relevant issues of the size effect of deep circular shaft excavation for intercity railway, based on a foundation pit project of Shenzhen-Daya Bay Intercity circular working shaft, the load-structure method are used to systematically analyze the stress and deformation characteristics of the circular excavation enclosure structure under different diameter conditions. The calculation results of the 3D spatial structure model and 2D elastic foundation beam model are compared. The influence of excavation size effect on the performance of circular enclosure structure is discussed. The results show that circular diaphragm wall is actually a quasi-circular structure, and it also produces a certain vertical bending moment under the action of soil and water pressure, which indicates that it is in a multi-directional stress state. It is feasible to use the simplified 2D equivalent model to design the circular foundation pit retaining structure, and the calculation results are more conservative than the 3D model. The spatial dimension effect has a significant influence on the performance of the circular enclosure structure, and its circumferential effect is very obvious when the diameter of a deep circular working shaft is less than 30 m .
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Research and Implementation of Urban Rail Integrated Management and Control Platform with Digital Twin and Multi-system Integration

hanxiaoyi

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In response to the increasing operation and maintenance pressure and efficiency requirements of urban rail transit, a comprehensive management and control platform based on digital twins and multi-system integration is constructed and implemented to achieve intensive and refined operation and maintenance management of subway stations and improve management efficiency and service levels. Through 3D scanning of existing lines, this paper constructs a digital twin model to depict the operation of urban rail, studies model lightweight technology and uses 3D rendering engines to render and optimize large models and large scenes. In addition, this paper studies multi-source heterogeneous data fusion technology through data standardize processing to realize the process-based collection and storage of heterogeneous data of various professions. Furthermore, develops a comprehensive urban rail management and control platform that integrates functional modules to meet the needs of various professions, the platform's efficient sharing of cross disciplinary data helps optimize the execution process of operation and maintenance tasks, shorten fault response time, significantly improves the accuracy of equipment and facility status monitoring, and enhances the effectiveness of preventive maintenance. The urban rail integrated management and control platform based on digital twin and multi-system integration has successfully realized the innovation of metro station operation and maintenance mode, significantly improved operation and maintenance efficiency, service quality and data utilization level, and provided an effective solution for the intelligent operation and maintenance of the urban rail transit industry.
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Design and Experimental Study of Adjustable Height Device for Low Melting Point Alloy of Rail Bridge

ZHU Jian, XIE Yayong, CHEN Gong, LI Pandao

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In response to the increasing speed and strict requirements for bridge smoothness in the design of rail elevated bridges, this article is based on the design of the elevated bridge of Beijing Metro Line 22 with a speed of 160km/h, and develops and designs a new type of adjustable height device based on low melting point alloy as the height adjustment medium. A series of experimental studies have been carried out, including the structural design of the device, indoor temperature and pressure tests, full-scale pressure adjustment performance tests of the compression shear machine, and on-site beam erection tests. The research results show that the new adjustable height device can achieve step less bidirectional height adjustment function, with a fast height adjustment speed, and can complete height adjustment within 30 seconds. The height adjustment accuracy can reach millimeter level, and it has good step less height adjustment performance and compression stability after alloy cooling and solidification. The accuracy and stability of this adjustable height device are not only important guarantees for the smoothness of elevated bridge beams, but also provide guidance for engineering applications such as replacing diseased bearings and adjusting bridge differential settlement.
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Structure Scheme and Mechanical Performance Analysis of Rectangular Prefabricated Metro Station

FAN Qi, LIN Fang, HUANG Meiqun, LI Mengting, PENG Zhiyong

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This paper focuses on the rectangular prefabricated station structure scheme developed and applied for the first time in Shenzhen Phase V Project. Combined with the evolution process of the prefabricated structure scheme with dry connection, this paper introduces in detail the section design scheme of rectangular structure scheme, structural partitioning and joint, bracing system of beam column, static and dynamic performance. The rectangular Prefabricated station structure scheme can be applicable to different station width requirements, and the adjustable template is used to effectively improve the universality of the rectangular structure components. At the same time, the rectangular structure can be expanded for different types of stations, such as three-layer two-span or two-layer three-span. In addition, the bending bearing capacity of rectangular assembled station joint is verified by full scale bending test, and the adaptability of the theoretical calculation method of the existing joint research to the structural size change is verified. The research results of this paper are intended to provide reference and experience for the subsequent prefabricated structure design and engineering application.
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Research on the key technologies of rectangular pipe jacking shell abandonment reception in water-rich soft soil area

zhangyuhua

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In order to solve the problem that the receiving end of rectangular pipe-jacking can not be provided with an open-cut receiving well, this paper analyzes the soil pre-reinforcement scheme in the construction of rectangular pipe-jacking receiving, studies the reasonable structural type of cast-in-place section of abandoned shell, and puts forward the waterproofing scheme between cast-in-place section of abandoned shell and precast pipe joints and hidden beams and columns of the station, combined with the new entrance project of Jingjiang Road Station in Tianjin Metro Line 2.The detailed processes such as shutdown of pipe jacking machine and grouting are optimized.The practice shows that the scheme can ensure the construction safety of the abandoned crust receiving, and the monitoring data show that the maximum surface settlement is 12. 12 mm.The key technology proposed in this paper has strong feasibility and good effect, which provides a new design idea for similar projects such as abandoned shell receiving due to the limitation of construction site..
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Key method for automatic generation of acceptance test sequences in CBTC engineering

ZHANG RUI, SI Xinyue, WANG Chenzhi

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Aiming at the problems of single method, long cycle time, low efficiency, high cost, heavy task and heavy workload of on-site engineering acceptance test of urban rail transit signalling system in China, a method applicable to automatic generation of on-site engineering acceptance test sequence is researched. Firstly, the constraints of the interconnection test case set for the urban rail signal system are analysed. Secondly, the line is divided into several independent test sections. Thirdly, the line characteristics are converted into a formal language that can be recognised by the computer to improve editing efficiency and the human-computer interaction experience. Then, the "auxiliary generation tool" is applied to automatically generate a number of field-executable engineering acceptance test sequences. Finally, a method for the automatic generation of on-site engineering acceptance test sequences is selected. The "auxiliary generation tool" is then applied to automatically generate a number of field-executable acceptance test sequences. Finally, actual lines are selected as test objects to verify the efficiency of engineering acceptance testing. The study demonstrates that test sequences designed using formal language can meet engineering acceptance requirements, cover 100% of interconnection test cases, shorten field test time, and improve test efficiency compared to the traditional method of manually designing test sequences.
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Research on the Technical Path ways and Methods of List-based Environmental Management in the Rail Transit Industry

liulei, zhangmin

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List-based environmental management is one of the important methods to clarify institutional boundaries and facilitate environmental impact assessment (EIA) reforms. Based on the features of rail transport, key points of planning EIA and project EIA, this paper analyzed the feasibility of implementing list-based management, developed lists of ecological environment zoning control, planning EIA, project EIA, environmental acceptance, and law enforcement inspection, and proposed pathways to aligning different lists in the rail transit industry. The results showed that the list-based management approach could specify the focus of attention of relevant departments that approve, plan, construct, evaluate the projects and administer justice by sorting out their responsibilities, therefore, help meet the requirements of environmental access and environmental protection, thus promoting the whole process environmental management for the rail transit industry.
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Measurement and analysis of the distribution ratio of traction return current in Guangzhou 25kV AC standard subway

SANG Guoyang, LIU Li, YA Shangsong, WANG Lingxiao, CHEN Xia, CAO Xiaobin

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Traction current return system is an important part of traction power supply system. If the current return system fails, it will cause damage to the primary and secondary equipment of traction power supply system, and even affect the normal operation of trains. At present, there is no research on real-time measurement of traction return current distribution for 25kV AC power supply system subway. In order to study the return current distribution law of its traction substation and verify the shortcomings of SCADA system's monitoring of return current, this paper designs a synchronous testing method to measure the current of each return cable. Based on the return path, it is divided into three groups: station return, parking lot return, and ground return, And studied the proportion and variation pattern of reflux current in different paths, and compared it with SCADA reflux current data.Research has found that although the reflux current fluctuates significantly over time, the reflux distribution ratio remains stable for the majority of the time, with only a few times experiencing fluctuations. The average reflux distribution ratio in each time period differs by less than 1%. However, the SCADA system cannot accurately reflect the changes in reflux current. This project has obtained the reflux ratio relationship of the traction substation through actual testing. The measurement and analysis method can provide reference for the reflux ratio relationship of similar substations and also provide direction for the improvement of SCADA system reflux monitoring.
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Micro Deformation Control Technology of Subway Deep Foundation Pits Construction Surrounding Buildings in Weak Strata

WANG Tonghua

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The control of micro deformation of adjacent buildings during the construction of deep foundation pits in weak strata is one of the challenges in the geotechnical field. Taking the construction project of subway deep foundation pit of adjacent buildings in soft ground in Hangzhou as an example, this paper introduced the micro deformation control technologies such as the reinforcement technology of underground continuous wall trough wall, sleeve valve pipe grouting reinforcement technology, servo steel support system, and the reinforcement and excavation technology of underground middle wall, and analyzed the deformation characteristics and the effect of micro deformation control technology in the construction of deep foundation pit of adjacent buildings in soft ground. The results indicate that the sleeve valve pipe grouting reinforcement technology reduces the impact of construction on the surrounding building group and suppresses its deformation; the deformation of the enclosure structure and surrounding deformation can be suppressed through slot wall reinforcement technology, and the quality of the enclosure structure has been improved; the servo steel support system effectively suppresses the deformation of the enclosure structure and reduces the impact of construction on the surrounding area; cross wall and block excavation technology suppresses building deformation and weakens the impact of spatiotemporal effects. In the end, the surrounding buildings of the deep foundation pit basically achieved the goal of "micro deformation".
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Research on Inter-connected Network Operation Technology of Urban Express Lines

TUO Xingbing, YANG Fan, ZOU Fei, LIU Shiqiu, CHEN Taotao

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In response to the current lack of experience in network operation of urban express lines based on fully automated operation technology in China, as well as the lack of corresponding operational reference standards and comprehensive technical solutions. Through the study of relevant literature, and empirical analysis of the operation schemes of Chongqing Suburban Railway BiTong Line and Urban Rail Express Line 27, this study investigates the network scheduling, train planning, and train organization of urban express lines based on fully automatic operation technology. This paper proposes the integration scheme of personnel except train dispatcher in the network dispatching hall and the arrangement scheme of multiple lines in the form of grouping under the network operation conditions of urban express lines interconnection.the paper also proposes the establishment process and principles of the train operation plan, the operation organization principles under the normal and abnormal operation scenarios, the cross-line operation scenarios between fully automatic and non-fully automatic trains.Through research, we aim to achieve an interconnected and network operation technology solution that integrates resources and improves efficiency from the line network to the line, and from the line to the line, which is conducive to achieving automatic cross-line operation between urban express lines, improving service levels, and promoting the construction of smart urban rail transit.
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Development of Driving Simulation Platform for Virtual Track Train

Wan Zhengyang, Zhou Hechao, Zhang Jimin

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The Virtual track train (VTT) has been put into commercial operation as a new type of urban rail transport in China in recent years. To further understand VTT’s operation performance, it is essential to develop a specific driving simulation platform to simulate VTT’s unique hybrid autonomous/manual driving mode. The main contribution of this paper are as follows: First, a vehicle system dynamics (VSD) model of VTT was established using SIMAPCK. Additionally, the control module for simulating the hybrid autonomous/manual driving mode of VTT was developed based on the model predictive control and Logitech driving simulation hardware. Furthermore, a driving scene visualization interface was established using Unreal Engine and Blender to simulate the real driving environment. These contents form a comprehensive simulation platform for the VTT. Simulation results demonstrate that the developed platform can effectively and accurately simulate the operational performance of the VTT under various driving modes, highlighting its significant engineering significance.
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Research on the Engineering of Applicability Degradation Scheme for Autonomous Train Operation System

FU JIAWEI

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The Autonomous Train Operation System (TACS) is the development direction of future urban rail transit signal systems and is partly being applied in some urban rail transit. Different from traditional CBTC, No unified TACS standard has been established yet, this paper aims to analyze the engineering applicability of existing TACS system degradation schemes. Based on the working principle of TACS, this paper discusses the necessity of configuring a degraded system ; based on the current development status of the TACS system, this paper summarizes three feasible TACS degradation schemes, introduces the architectures and working principles of different degradation schemes, and qualitatively analyzes the three TACS degradation schemes from the aspects of system composition, application scenarios, and tracking ability under degradation situation. Establish the train tracking time model under degradation situation, and simulate the degradation train tracking scenarios of three TACS degradation schemes under the same engineering conditions. Based on the simulation results, identify the factors that affect the efficiency of degradation tracking. On the basis of the above research, the key conditions for the TACS degradation system are summarized, and the engineering applicability and application effects of the three degradation schemes are analyzed, some improvement suggestions are proposed. The results of this article have guiding significance for the promotion and application of Train Autonomous Operation System (TACS).
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Analysis of the impact of urban rapid transit pressure on train airtightness measures

WU Minhui, LIU Jianchao, ZHANG Ge, WANG Luping, DUAN Haibin

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In order to analyze the effects of tunnel diameter, portal cushioning devices, and train airtight measures on pressure waves inside and outside urban rapid transit trains, a three-dimensional finite element analysis model including the tunnel, train, and portal cushioning devices was established. The matching between the tunnel diameter and the train airtight index was calculated and analyzed, while the effects of portal cushioning measures on pressure waves were also analyzed. Combining with the new technologies and manufacturing processes of trains, the setting of portal cushioning devices can effectively control the peak pressures inside and outside the train, and specific airtightness requirements for vehicle components such as doors, air conditioning, car body, gangways, etc. are proposed. These requirements can meet the needs of airtightness of urban rapid rail transit trains, providing important references for the transmission of pressure waves in urban rapid rail transit and the control measures of airtightness index of various parts of trains.
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Planning and Practice of Public Rail Facilities for TOD Project

Wang Chunsen, Xing Min, Xiao Tipeng, Kang Qiyang

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Abstract: With the acceleration of urban development, the construction speed of urban rail transit in various cities is gradually strengthening, The TOD comprehensive development model centered on public rail facilities has been widely applied,and more and more transfer stations and integrated transport hubs are emerging.The domestic rail transit TOD is gradually developing towards diversification, and the concept of station city integration is helping the rail transit TOD to reach a new peak. Large scale rail transit TOD projects generally require planning in the early stages of the project, based on advanced planning and coordinated design methods, which are more conducive to the implementation of the main body to create a comprehensive transportation hub project with core characteristics in the area. This article focuses on the problem of mismatch between the core development area of Dongguan and the timing of rail transit construction. It summarizes the practical path from early planning to implementation based on line network and detailed planning research, and innovatively proposes the construction of public rail facilities co construction engineering. The model of advanced planning, coordinated design, and integrated construction brings new design concepts. The research results indicate that the construction of public rail facilities according to the underground space model has solved the problem of urban comprehensive hub locations being unable to be developed synchronously due to the inability to initiate and implement rail transit projects, providing new research directions for subsequent project development, design, and implementation, and providing successful cases for government decision-making.
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Train-induced structural vibration response model based on mobility theory

Lu Qingquan, Chen Jialiang, Zou Chao, Li Xuming, Ma Liqiu, Wang Zhe

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In order to quickly and reasonably predict the vibration response of buildings along subway lines, the building structural system is decomposed into two parts: a propagation structure and a response structure, based on the theory of mechanical mobility. The bearing structure is assumed to be a beam element model, and the slab structure is considered a plate element model. The mobility formula and corresponding matrix expressions of each unit system are derived, and the train-induced structural vibration response model is then constructed. The reliability and correctness of the model were verified by combining it with on-site testing. The study shows that the structural responses predicted by the mobility theory-based model in both the time domain and frequency domain have a high degree of consistency with the measured vibrations; in the frequency domain, the maximum error of the center frequencies of each 1/3 octave band does not exceed 5 dB, indicating that the proposed train-induced structural vibration response model can quickly and effectively predict the structural vibration response, and the outcomes can provide theoretical support for vibration prediction along subway lines.
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Design and application of ultrasonic guided wave rail fracture monitoring system

ZHOUYONGJIU, FengJiaSheng

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In order to monitor rail health in real time and realize early warning of rail fracture damage, this paper proposes a broken rail detection method combining ultrasonic guided wave detection technology and variational mode decomposition signal processing technology. According to the requirement of rail fracture detection, the system workflow and the hardware circuit of each module are designed and constructed. The three-dimensional rail model is established in the finite element simulation software to explore the propagation speed of ultrasonic guided wave in the rail and the feasibility of signal noise reduction method. Through the equipment installation test in Suzhou Metro Line 5, the method of artificial simulation of broken rail defects is used to verify the effectiveness of the monitoring system. The test results show that: when the rail is broken, the remote alarm time of the system is 3 minutes, and the fault location accuracy is 98.9%, which provides an effective means for rail fracture monitoring.
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Travel Mode Choice Behavior under Rail Transit?Abnormal Conditions based on Cumulative Prospect Theory

zhang xiao lin, xiong zhi hua

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When the traffic system is abnormal, passengers are prone to have blindness, panic, conformity and other psychology, and make incomplete rational decisions.This is inconsistent with the complete rational assumption and complete information assumption in the existing passenger travel behavior model, such as MNL. Therefore, the incomplete rationality of passengers under abnormal conditions is described through the cumulative prospect theory,and consider individual differences among passengers to solve the inability of classical MNL model.Firstly, comprehensively considering the four factors of time, cost, comfort and convenience, a model of rail transit non normal passenger travel mode selection based on cumulative prospect theory is constructed.It used to characterize the incomplete rationality of passengers.Afterwards,a questionnaire survey is conducted to calibrate the model parameters for rail transit abnormal conditions. Based on the survey results, a differentiated reference point following a Poisson distribution is constructed to describe the reference point dependency phenomenon of the model.Individual differences among passengers are introduced into the model to explain the essence of different decision-making outcomes among passengers.Finally, the results of the case study indicate that the Poisson distribution test value with the introduction of differentiated reference points meets the test criterion of greater than or equal to 0.05. It explain the essence of passengers' different decision-making results, and presenting a trend of comprehensive prospects fluctuating with the reference points.This model focuses on abnormal situations and reflects the incomplete rationality and individual differences of passengers when facing abnormal situations.The overall accuracy is higher than MNL model, and the average absolute error is reduced by 4.9% .The accuracy of microscopic calculation results has been improved by 25.4% compared to the MNL model. It can provide theoretical support for traffic demand prediction under abnormal conditions of rail transit. However, under the influence of the principle of loss aversion, the division rate of certain methods will be reduced. The accuracy at the micro level needs further improvement.
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Research on rail transit operation safety risk prevention and control system based on artificial intelligence technology

lizhigang

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In order to adapt to the development of modern rail transit operation high quality, improve security risk control ability, based on artificial intelligence technology application of rail transit operation safety risk prevention and control system research, research and development of urumqi metro safety management platform, the artificial intelligence technology such as big data into the safety production management, management, management methods support innovation and perfect, improve the site safety management in rapid perception, real-time monitoring, advance warning, dynamic optimization, intelligent decision-making, linkage disposal, system evaluation, global coordination, etc. System covers the subway operation safety management foundation work and key work, mainly for dual prevention system, operation process dynamic management, safety production standardization, etc., with information foundation ability supplement as the goal, the construction of hidden risk classification control, management, safety supervision and inspection, safety think-tank, emergency disposal, dangerous operation management, early warning and prediction function module. It realizes the digitalization and intelligence of enterprise security management, and improves the ability of security risk prevention and control.
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DBN-based Reliability Evaluation of LTE-M Train-ground Radio Communication System

Yang An yu

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With the development of metro radio communication system, the use of LTE technology to carry CBTC, PIS, CCTV and other services to build a comprehensive platform for the train-ground network has also become a development trend. In order to solve the problems of dynamic failure and different services in the reliability analysis of LTE-M train-ground radio communication system, this paper evaluates the reliability of LTE-M train-ground radio communication system based on dynamic Bayesian network (DBN). The reliability block diagram which is constructed on the basis of analyzing the LTE-M system structure and function, is transformed into a dynamic Bayesian network, and the DBN structure and parameter modeling were conducted. Based on the forward inference of DBN, the reliability of LTE-M system is obtained and compared. Based on the backward inference of DBN, the weak points of LTE-M system are recognized to provide reference for operation and maintenance. The results show that the LTE-M system has high reliability; Building base band unit and train access unit are the vulnerabilities of the system, which need to be focused on. The proposed approach can improve the intelligent maintenance level of LTE-M train-ground radio communication system.
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Analysis on the causes of water leakage at shield segment joints and research on optimization measures

shanxiaobo, liyilun

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In the overall structure of shield tunnels, segment joints are the weakest part of the waterproofing system and the most important part of waterproofing design. Currently, shield tunneling construction is undergoing many attempts and innovations, and changes in structural design and construction methods may lead to leakage of water or damage to sealing pads at segment joints. In order to solve the problem of water leakage at the joints of shield tunnel segments, starting from the waterproof principle of elastic sealing gaskets, this paper analyzes and summarizes the material, bonding process, and structure of elastic sealing gaskets, and finally proposes specific optimization measures. In addition, based on the actual case of the new segment shield tunnel project in Jiangxinzhou, Nanjing, this study analyzes the impact of tunnel innovation on joint waterproofing, proposes many optimization measures, and continuously monitors the actual waterproofing effect and tunnel forming quality after the tunnel is completed. The monitoring results show that the tunnel forming quality is good, and the waterproofing effect is far superior to traditional tunnels.
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Study and Optimization of Mask R-CNN Algorithm for Surface Defect Detection on Railway Tracks

liangzhen, 贾超, 赵晨

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Surface defect detection technology plays an important role in railway inspection to effectively prevent railway accidents and ensure operational safety. This paper addresses the issues of poor detection accuracy and low sensitivity to small targets in existing railway defect detection technologies. For the Mask R-CNN (Mask Region-based Convolutional Neural Network) algorithm model, a model improvement scheme is proposed by incorporating an attention mechanism. This scheme introduces a Channel-wise Spatial Module (CSM) into the feature extraction network for instance segmentation defect detection, effectively eliminating interference information, obtaining multi-scale feature representation, and obtaining more spatial information and better shallow information, thereby enhancing the edge detection capability of surface defects on railway tracks. In the same experimental environment, compared with the Mask R-CNN algorithm, after adding CSM, the mAP value of the Mask R-CNN model increased by 6.5%. Among them, the AP values for the recognition of "depression," "crack," and "fatigue wear" defects on railway tracks increased by 6.3%, 6.9%, and 6.1%, respectively. Horizontal comparison shows that the Mask R-CNN model with CSM, compared with the Fast R-CNN model, improved the segmentation effects of the three defects by 11.6%, 12.5%, and 12.9%, respectively; meanwhile, compared with the Faster R-CNN model, the segmentation effects of the three defects improved by 8.8%, 10.0%, and 10.3%, respectively. The work in this paper demonstrates that the Mask R-CNN model with CSM can better recognize three types of defects, improve detection accuracy and sensitivity to small targets, and provide more secure and powerful technical support and guarantee for intelligent track inspection.
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Analysis and Understanding of the Experience of Rail Transit Planning and Construction in Macao

Jin Wei, Xiao Ripeng, Cheng Tan, Wen Xin

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In order to enhance the capacity of the urban transportation system, promote sustainable transportation development, achieve green development goals, and provide more and more reliable travel options for Macau residents and visitors, the Macau government is actively promoting rail transportation planning and construction. This paper analyzes the history and current situation of Macao"s rail construction, recognizes the prerequisites of Macao"s rail development planning in terms of supporting the urban pattern, enhancing transportation capacity, optimizing transportation structure, and following public will, and summarizes the technical points of Macao"s rail deployment in terms of serving the main corridor, linking the main hub, integrating multi-modal, and coordinating spatial relationships, for reference of related cities in developing rail transportation. Keywords: Urban Rail Transit; Rail Transit with medium traffic volume; Transportation Capacity; Public Willingness
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Research on dedicated rail return current scheme based on contact rail power supply traction power supply system

Sun Jianjun, Xing Chunyang, Lan Huifeng, Li Guoyu, Li Chuanhui, Huang Qilai

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The urban rail transit projects in China have adopted overhead contact system power supply and dedicated rail return current scheme to solve the problem of stray current leakage. However, at present there is no application case of dedicated rail return under contact rail power supply system in China. This article proposes four dedicated rail return current schemes based on the contact rail power supply system. From the aspects of equipment impact, vehicle current return, networked operation of each line, power supply system protection, safety and cost-effectiveness, etc., this article analyzes and evaluates the four proposed dedicated rail return schemes through quantitative and qualitative methods, discusses the feasibility, advantages and disadvantages of each scheme, and finally proposes a recommended dedicated rail return scheme based on the contact rail power supply system, and summarizes the impact of dedicated rail return on other disciplines.
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Deformation Control Technology of High-speed Railway Bridge Sidecrossed at A Small Angle by Shield Tunneling in Sandy Stratum at A Small Angle

ZHOUXIN

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This article combines the geological deformation mechanism caused by shield tunneling construction and uses the three-dimensional numerical simulation method to simulate the displacement of bridge piles during the small angle side crossing of high-speed railway bridge group piles in a subway shield tunnel in sandy. The validity of the bridge protection measures are verified, and the key technical points for controlling deformation of the bridge are identified. This is verified through engineering practice, and the normal operation of high-speed rail is ensured.
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Study on the early temperature field and strain variation law of concrete on the side wall of subway station

CHEN Weiwen

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Abstract:

This paper monitors the construction process of side walls by embedding temperature and strain sensors, and compares the measured data with the Midas civil finite element model to summarize the law of temperature field and stress field in the construction process of side walls. Field monitoring and numerical analysis show that ,the hydration heat reaction of concrete in the early stage is relatively fast, and the maximum value is reached only 20h after pouring. The temperature is high in summer, and the cooling rate is relatively slow, about -0.40℃/h, and the cooling rate of the middle layer is relatively fast. The time when the compressive stress reaches the maximum value is close to the time when the temperature reaches the maximum value. Then it enters the shrinkage deformation stage. After the critical condition of 0 stress occurs, the tensile stress increases gradually with the continuous decrease of temperature, and the tensile stress at each measuring point tends to be stable at 50h after pouring. The finite element model is close to the field monitoring data, which can play a certain role in prediction, and can play a theoretical basis and reference role for the actual fracture control in engineering.
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An Identification Method of Faulty Train for A Straddle-Seat Monorail DC Traction System

Zhang Xiangliang, LIU YONG SHENG, 蔡志端, 王孝顺, 罗四倍, 单丰, 祝艳华

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When a short-circuit fault occurs between positive pole of high-voltage DC circuit for a train and its carbody inside the station in a straddle seat monorail DC traction system, this causes carbody grounding relay（GR）of all trains inside the station to action and circuit breakers of the train to trip.Meanwhile, this also brings about multiple 64D grounding protections action and trip circuit breaker of the DC feeder.The fault arouses loss of power to the DC traction system. This is necessary to identify the faulty train and restore normal power supplying of the DC traction system as soon as possible in order to reduce the impact of the accident.First, the paper analysed characteristic differences in the amplitude of grounding current and negative receiving electricity current for faulty train and normal train when short-circuit occured between the positive circuit and the carbody based on the equivalence model of DC traction bipolar power supply system for straddle monorail transportation. Second, identification method of faulty train was proposed based on the comparison of grounding current and negative current amplitude. The faulty train identification procedure was activated when the grounding current amplitude was greater than the setting value. In this case the train was judged to be faulty if the magnitude of grounding current was greater than the magnitude of negative receiving electricity current，but it was recognised as a normal state if the former was less than or equal to the latter. Finally, the correctness and effectiveness of the proposed method was verified by MATLAB simulation and field test. The method is simple, practical and highly reliable, which can provide a strong guarantee for the safe operation of straddle-seat monorail traffic.
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A Summary of the Development of Pure Electric Braking System and Key Technologies for Urban Rail Trains

Zhihong Zhong, Zhongping Yang, Fei Lin, 石春珉

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At present, the common braking method adopted by most urban rail trains is the electropneumatic braking. However, due to the disadvantages of poor controllability and slow response of air brakes, it will result in inaccurate parking and poor comfort. As well as issues such as greater loss, if you can replace air brakes with electric brakes, you can overcome these problems. In order to truly realize pure electric braking and make it necessary to replace air braking, on the one hand, it is necessary to satisfy the maximum torque output capability in the full-speed range as much as possible; on the other hand, it is necessary to ensure the accuracy of the speed measurement at low speeds. The controllability of the torque output and the control effect of the jerk have good performance. Based on the development history of pure electric brake, this paper expounds the status quo of pure electric brake application and the main problems to overcome. From the perspectives of high speed and low speed, the difficulties of pure electric brake and the corresponding problems are described in detail. The solution to the problem, and summarized for each difficult issue, and looked forward to the future development direction.
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Research on Overvoltage Suppression during Operation of Rail Potential Limiting Devices in Urban Rail Transit

Tang Yuning

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In order to ensure personal safety, over voltage protection devices are usually installed in stations and depots of operating lines, OVPD)， However, the overvoltage generated during the reset of the rail potential limiting device OVPD may cause the OVPD section II to act or even lock, resulting in the rail potential limiting device short circuiting the ground and rail, becoming a path for stray current leakage. With the continuous increase of urban rail operation mileage, stray currents have caused serious problems such as DC bias in the surrounding power system and corrosion damage to the urban pipeline network, which have seriously threatened the safe operation of the power system and oil and gas system. This paper proposes a suppression method for the overvoltage caused by the mis-operation of the rail potential limiting device caused by abnormal rail potential, which exacerbates the leakage of stray currents in urban rail transit. The method involves constructing a simulation model of the overvoltage generated by the OVPD opening of the rail potential limiting device, constructing an arc experimental platform using N1250 contactors, and conducting grid mounted testing on actual lines. The results show that after using the overvoltage suppression method proposed in this article, the peak operating overvoltage generated by the opening of the rail potential limiting device will be significantly reduced, reducing the possibility of OVPD mis-operation and reducing stray current leakage.
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Research on Key Technical Solutions for Train Control System Supporting the Integration of Four Networks in Rail Transit

ZHANG Youbing, 崔佳诺, 陈志强, 王建敏, 王佳

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In recent years, achieving the integration of the four networks and improving the overall transportation efficiency of the rail transit system has become a research hotspot and development direction. From the perspective of the signal system, the key to achieving "four network integration" is to achieve the integration of the CTCS system of the high-speed railway and the CBTC system of the subway. Using the existing mature CTCS system and CBTC system as technologies, research the key technologies of train control system that support the integration of four networks, solve the technical problems of incompatibility between the two systems, achieve interconnection and interoperability, and support safe and efficient cross line operation of trains. This article studies the key technologies of train control systems that support efficient cross line operation of CTCS and CBTC, including onboard equipment, ground equipment, and overlap area design. It also provides a detailed description of the specific process of cross line operation without stopping in automatic driving mode. Cross line operation is achieved through compatibility of on-board equipment with ground equipment, reducing the number of ground equipment, simplifying the system structure, providing system security, reliability, and maintainability, and also having significant cost advantages; Adopting integrated on-board equipment with a simple system structure, low equipment cost, and low requirements for installation space is the main direction of future technological development; The key technologies of the train control system compatible with CTCS and CBTC proposed in this article can be used to guide system design, research and application, and have important guiding significance for achieving "four network integration".
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Research on Advanced Persistent Threat (APT) Detection Technology for Typical Application Scenarios of Urban Rail Transit

ZHANG HONGJUN, LYU MO, GAO YANG

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In order to solve the problem of how to effectively deal with Advanced Persistent Threat (APT) in urban rail transit scenarios.This paper proposes a method that combines attack source graphs with deep traffic learning to integrate attack reconstruction and traffic monitoring to realize the judgment and detection of APT attacks. It can be seen from the experimental results that this model can effectively trace the source of APT attacks. In comparison with traditional APT attack detection models based on sandbox or abnormal characteristics, this combined model has obvious advantages in detection accuracy, precision, recall rate and other indicators.
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Finite element analysis of the influencing factors on the floating of shield tunnel segments in soft soil strata

张宝成, 贺文喆, guo yongjian, 罗治斌, 黄明利, 吴啸宇

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In order to study the influence of excavation speed and slurry gel time on the segment floating of shield tunnel, this paper uses Winkler elastic foundation beam to establish a three-dimensional finite element load structure model of shield segment based on the shield interval between Tongyuan Road Station and Xinggang Street Station of Suzhou Metro Line 5, and analyzes the influence of excavation speed and grouting gel time on the segment floating and dislocation. The research results indicate that the floating and staggering of the segments increase with the increase of shield tunneling speed. The floating mainly occurs at the bottom of the segments in the non solidified slurry section, and the staggering mainly occurs at the junction of the non solidified slurry section, the shield tail section, and the slurry solidification section. To avoid the floating and staggering of the segments exceeding the specification requirements, the shield tunneling speed cannot exceed 10 cycles/d. Secondly, with the extension of grout gel time, the segment floating amount and dislocation amount gradually increase. The use of quick setting and early strength double grout for back grouting is conducive to the control of shield tunnel floating.
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Research on the Integrated Development of Multi-level Rail Transit in the Guangdong-Hong Kong-Macao Greater Bay Area

LIU PENG

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This article adopts an empirical analysis research method to analyze the current problems of multi-level rail transit development in the Greater Bay Area, such as insufficient integration across levels, standards, and regions, as well as a lack of unified policy system design and command and coordination institutions. This paper proposes the establishment of a joint conference system for the integrated development of rail transit in the Guangdong-Hong Kong-Macao Greater Bay Area. Strengthen the planning and construction of multi-level rail transit in the Greater Bay Area; Further strengthen cross-regional management and coordination of multi-level rail transit construction; Study and solve the problem of intercity passenger and cargo transportation in urban agglomerations in the Bay Area; Use land policies to support rail transit construction and improve investment policy support; Suggestions on the establishment of a multi-level rail transit operation enterprise alliance in the Greater Bay Area.
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Experience and Inspiration of Crossrail Line Investment and Financing In London Suburban Railway

刘畅

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In view of the contradiction between the construction intention and financing situation in China, this study adopts the case study method to study the investment and financing mode of London suburban railway. This paper firstly introduces the general situation, opening process and social and economic benefits of Crossrail suburban railway line, and secondly focuses on analyzing and discussing the proportion and amount of central and local government investment, the proportion and amount of different beneficiary entities' investment in the mode of "co-investment by central government and local government + contribution by beneficiary entities". Finally, the investment and financing experience of the line is summarized from the central and local co-ownership, attracting social beneficiaries, TOD integrated development, and attracting other transportation enterprises, This study brings new cases, new ideas, and new concepts for the investment and financing of suburban railway and even the entire urban rail transit industry in China.
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Research and Application of Subway Line Design Combination Scheme In Special Environment

renbineng

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In view of the fact that the conventional subway line design method cannot solve the problems of large amount of demolition, difficult construction, high risk and high cost in the dense section of the building (structure) under construction.This article innovates a line design method that combines a special scissors crossover with a curved island type misaligned platform, which not only meets the design needs of related professions such as architecture, structure, signal, track, train operation, and line, but also allows subway lines to flexibly avoid dense buildings around the station. The research results indicate that this innovative route design method can achieve the goals of reducing demolition, increasing construction clearance, reducing open excavation scale, reducing construction difficulty and risk, and saving engineering investment. It provides technical guidance for areas with dense buildings, demolition, and construction difficulties around subway stations. The application of practical engineering cases shows that this innovative line design method can generate good economic, technical, and social benefits.
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A Novel Evaluation Perspective: ESE Evaluation Theory and Method and the Assessment of the Sustainable State of Urban Rail Transit

YU Songwei, LIU WeiYang, Taoyuan, Chen Mingdian, ZHONG Yingying

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This paper introduces a new way to evaluate thinking—the ESE Theory and Methodology, providing new theoretical support and practical pathways for assessing engineering projects such as urban rail transit and other large infrastructure. The paper proposes that data possesses three attributes defined as ESE, and uses these as the axes to construct an ESE Cartesian coordinate system, representing all business scenarios in urban rail transit. Within this three-dimensional ESE space, the sustainable development status of urban rail transit is divided into "eight types in four categories," achieving a visual representation of the sustainable development state of urban rail transport and quantifying the degree of sustainable development.
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Research on smoke exhaust efficiency of urban rail transit station hall under different smoke exhaust vent modes during fire

FAN Le-le

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In response to the current rough smoke exhaust conditions in the public area of the subway station hall, which generally involves opening all smoke exhaust outlets in one smoke control zone, the existing smoke exhaust layer is damaged to a certain extent and the smoke exhaust efficiency is underground. This article focuses on eight different smoke exhaust conditions in the public area of a certain urban rail transit station hall in Zhengzhou, and studies the smoke exhaust efficiency of opening smoke exhaust outlets in different positions. Through FDS simulation, this article obtains the distribution maps of visibility, temperature, and CO concentration over time under different working conditions. It is concluded that: 1) When a fire occurs in the public area of the subway station hall, the more smoke exhaust outlets are opened, the better, but it is determined by the opening position of the smoke exhaust outlet; 2) Opening the smoke exhaust outlet during the horizontal spread stage of smoke will interfere with the horizontal stratified flow of smoke, intensify the heat and material exchange between the upper layer of smoke and the lower layer of cold air, resulting in a decrease in the height layer with a temperature of 60 ℃ and a visibility of 10m, which is not conducive to personnel evacuation; 3) The smoke exhaust outlet near the smoke blocking vertical wall in the middle of the public area on the station hall level needs to be opened normally to smoothly discharge the accumulated fire smoke in that area.
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Study on Environmental Vibration and Propagation Law of Brick-Concrete Structure Induced by Subway

WANGZhengang

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In order to solve the problem of environmental vibration of adjacent brick-concrete structures caused by subway operation.In this paper, a 7-storey brick-concrete structure was used as the study object. The vibrations at tunnel, outdoor ground and structural floor were measured to analyse the propagation law of vibration along the path of "tunnel - ground - structure", and thus the possible reasons for exceeding standards were analyzed: The shallow burial depth of the tunnel, the proximity of buildings to the tunnel, and their coexistence in the same soil layer result in poor attenuation of vibration by the soil. Additionally, the resonance of certain floor slabs within the structure leads to vibration responses exceeding the evaluation standards for outdoor ground and the first floor indoors. The finite element model of this brick-concrete structure was further established, and the measured vertical acceleration at the bottom of the columns was used as the load. The accuracy of the model was verified by comparing the measured floor response. The calculations confirm the amplification effect in the middle or top floor. The influence of the number of floors, storey height, slab thickness and wall thickness on the spatial distribution of vibration response was obtained by parametric analysis. The conclusions can be informative for the environmental vibration evaluation of such structures.
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Study on the Noise Reduction Effectiveness of Diffusion Type Sound Barriers in Metro Access Lines

XU Ping, DU Xuanqi, He Kuang, YANG Yanfeng

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The access line of Zhongzhou Avenue depot in Zhengzhou metro line 5 is taken as an engineering example, the noise are in-situ tested before and after the installation of sound barriers, the noise reduction process is simulated with Virtual Lab software, the simulation results have good agreement with the tested sound pressure level changing with the sound source frequency, and the accuracy of the acoustic simulation model and calculation method is verified. The insertion loss of sound pressure level is adopted to characterize the noise reduction effectiveness of the sound barrier, and further research are conducted on the noise reduction effectiveness of triangular wedge, QRD sequence, PRD sequence and micro perforated panel - PRD I composite sound barrier, and the results reveal that: wedge angle has a significant impact on the noise reduction effectiveness of the triangular wedge sound barrier; the higher irregularity has profit to increase the diffusion effect for diffracted sound of PRD sound barrier, and PRD sound barrier has better noise reduction effectiveness than QRD sound barrier; the overall noise reduction effectiveness of PRD type I sound barrier is slightly higher than that of PRD type II sound barrier, to reduce properly the design frequency of the diffusion body, increase the order, and expand the slot width can improve the noise reduction performance of the PRD type I sound barrier; to add micro perforated plate resonance sound absorption structure in the diffuser end groove of micro perforated panel - PRD I composite can further increase the noise reduction of the end structure of diffuser, which would have an ideal application prospect for improving the noise environment of metro access lines.
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Research on Standardization of Transport Services for the Daxing Airport Express

WEI Wei, LI Peng, CAO Ran, YUAN Zheng, YAO Xiangming

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The Daxing Airport Express is a special rail transit line that serves Daxing International Airport, which is different from the ordinary urban rail transit line in terms of functional position, service passengers, passenger flow characteristics, and service standards. However, it is lack of transport service standards for this type of special transit lines. In order to improve the service quality of the Daxing Airport Express and match service standards of air traffic, it is important to design specific service standards. First, the particularity of the special line is analyzed from the aspects of service passengers, technical conditions, passengers’ travel needs, etc.; Second, analyzing the existing service standards of rail transit, and then expounds the necessity of establishing transport service standards for these special lines; Finally, providing suggestions for designing service standards from the aspects of design principles, standard framework, and key contents of services. This study aims to provide reference for the formulation of service standards for the special rail transit airport line.
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Thinking About the Planning of Beijing Rail Transit Line and Station Based on Integrated Station-City Development

Zhang Bawu, Li Ying

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In recent years, with the comprehensive transformation and upgrading of the national economy, Beijing's urban development mode has also undergone a transformation, with more emphasis on scientific, sustainable and high-quality development and construction. The relationship between rail transit and urban development has also been re-examined, and the planning concept of "urban follow-track construction" has emerged. This paper analyzes some of the problems existing in the development of the current situation of Beijing's rail transit, summarizes the experience of the integration and development of rail transit station cities, sorts out the policy guidelines related to the integration of station cities in Beijing in recent years, and puts forward new understandings and thoughts on the station planning concept of rail transit lines. In the aspect of urban rail transit line network planning, emphasis is placed on the selection of corridors and nodes, strengthening the interaction with urban planning. In the aspect of route planning, attention is paid to the resource matching between stations and land, balancing the win-win relationship between planning and construction.Combined with the experience of actual engineering projects, the new concept of planning is applied to engineering practice, and it’ll provides a reference for the implementation of the integrated development of Beijing rail transit station city.
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Measured Analysis of Vibration Source Strength in Metro Tunnel Influenced by Vehicle Condition Factors

LIU Wenwu, FENG Qingsong, LUO Xinwei, QI Yingrui

Abstract: (109) HTML (0) PDF (0.00 ByteKB) (0)

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In order to analyze the influencing factors of the vibration source strength of subway tunnel, taking the straight line section of a subway line as the research object, the vehicle-induced vibration signals and velocity signals were collected synchronously, and the time-domain and frequency-domain characteristics of all-day test samples were statistically analyzed. The results show that during peak hours in the morning and evening, the vibration response inside the tunnel may not be completely maximum, and the degree of dispersion of the vibration source intensity is directly related to the vehicle state. The average difference in the VLZ of the tunnel wall measurement points caused by V1 and V2 vehicles is 6.7 dB; Take more than 40 sets of test samples to calculate the intensity of the vibration source, and the results are closer to the daily sample mean; The main frequency of tunnel vibration caused by the wheel rail system shifts with the change of vehicle speed. The vehicle speed shows a strong linear positive correlation with the vibration acceleration level of the track bed and tunnel wall. For every 10km/h increase in vehicle speed, the vibration increases by about 1.7dB and 2.6dB, respectively; When the speed difference is within 10km/h, the vibration source intensity changes within 1dB, and when the speed difference is between 10-20km/h, the increase is about 1.5-2.2dB; The coefficient of speed-corrected CV is calculated to be 18.5, which is close to the coefficient used for train speed correction in the vibration prediction formula; the tunnel wall vibration is more discrete in the low-frequency band below 40 Hz, but the contribution of this band to the source strength of vibration is small, accounting for 15.29%, and the dominant frequency band is 50-63 Hz, which contributes to the source strength of vibration by 59.55%. The research results can provide a reference for the further accuracy of the vibration prediction formula, and provide a theoretical basis for improving the accuracy of the metro tunnel source strength test results.
1
Optimization Design of Integrated Development Vehicle Base

Wang yali

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In order to solve the problems of construction and operation caused by the development of the upper cover, it is necessary to adjust and optimize the general layout of vehicle base, fire fighting, traffic organization, pipelines, vibration and noise reduction. Based on the analysis of the difference between the development and non-development of the vehicle base, this paper puts forward the optimization strategy of“One center, two principles”, which is based on the problem-oriented theory and the premise of ensuring the scale and function of base, not only create good conditions for the development of the upper cover, but also ensure the safety and environment under the cover, this paper expounds the optimized design ideas from the aspects of site selection, general plane layout, maintenance technology, fire evacuation, ventilation and smoke exhaust, traffic organization, etc. , such as adopt new maintenance equipment, strengthen evacuation and smoke prevention and exhaust, to eliminate the adverse effects of the development of the upper cover as much as possible, so as to achieve the coordination, mutual benefit and win-win.
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Assembly Attitude Analysis of Prefabricated Walls in Large-diameter Shield Tunnels of City Line

WU Yukai, Tang Zeren, 吴玉凯, Liu Xian

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In order to control the assembly quality of partition walls in large-diameter tunnels, this paper investigates and analyzes the assembly attitude of prefabricated partition walls of Shanghai Airport Link Line. After specifying the coordinate system of partition walls, assembly attitude of the partition walls with and without initial assembly error is studied, and attitude information of the partition wall and analytical expression of its bottom plane equation are obtained under each working condition. The analytical results reveal that: 1) When there is no initial assembly error of partition walls or only the initial assembly error of translation or rotation, the selection of different control points and jacking sequence of regulating system will not affect the assembly control of partition walls. And the assembly attitude can be controlled according to the obtained expression of the attitude of partition walls. 2) When partition walls have only initial assembly error more than translation or rotation, the attitude of partition walls should be controlled according to the adjustment system, which is based on different jacking sequences of regulating system. And then the assembly of the partition wall can be controlled according to obtained expression to improve the assembly accuracy of partition walls. 3) The analytical formula is applied to the construction of partition walls, and good engineering application results have been achieved.
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Numerical simulation analysis of the dynamic loads distribution in subgrade of metro depot

LIU Yaqiong, XIE Yunqi, REN Lei, ZHAO Xiaohua

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The design standards for the roadbed structure of the metro depot have not been clearly defined in the "Metro Design Specification(2013)", and the current practice of using the main line standard results in high and unreasonable costs. This article relies on the Zhengzhou Metro Tieluxi Depot project to carry out numerical simulation analysis of dynamic loads under different subgrade structures, and studies the variation law of dynamic load distribution. The dynamic load generated by ballastless track at the same train speed is smaller than that of ballasted track. The increase in the thickness of the subgrade surface layer has a more significant effect on reducing the dynamic load generated by train operation. However, an excessively thick foundation will increase the stiffness of the roadbed, which is not conducive to stress dissipation. Therefore, when the foundation thickness is increased to a certain extent, the effect of reducing dynamic loads gradually becomes less significant. The numerical simulation results show that the design scheme of the metro depot subgrade can appropriately increase the parameters on the basis of "0.3+0.9" and "0.4+0.7", ensuring that the dynamic and static stress ratio of the subgrade is strictly less than 0.2, achieving the best level of safety and economy.
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Research on the Countermeasures of Service Improvement under the Bus-like Operation of Intercity Railway in Guangdong-Hong Kong-Macao Greater Bay Area——An example of Guangfo metropolitan

DAI Zhi, WANG Xiaolong, HANG Yanbin, QIN Yu

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Accelerating the construction of a commuting circle with rail transit as the backbone provides important support for the cultivation and development of modern metropolitan areas. In order to better play the effectiveness of the intercity railway in the Guangdong-Hong Kong-Macao Greater Bay Area(GBA), the operating entities and modes have been adjusted in recent years, gradually transferring from the original railway operation departments to local metro operators following the public transport model. By analyzing the issues related to unclear functional levels, lack of coordination with urban development, insufficient networked operation, and low service efficiency of the intercity railway in the GBA, this article proposes to reintegrate and re-examine the various levels of tracks, including intercity railways and city-wide express lines, based on their functional hierarchy. It also recommends considering the network layout in combination with the travel demand characteristics of the metropolitan area, optimize the external corridor of the metropolitan area, and strengthen the fast direct connection channel of the core area. using station sidings and connecting lines to further enhance the interconnection of metropolitan area railways, and optimizing the transfer services between intercity stations and subways. These suggestions can provide some reference for the improvement of service and sustainable development of intercity railway.
1
Modal analysis of subway bogie frame based on environmental excitation

Bie Bilong, 黎少东, 潘彦凌, 琚永刚, Shu Yao

Abstract: (91) HTML (0) PDF (0.00 ByteKB) (0)

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A large number of practical cases have shown that fatigue failure of subway turnstile structures is mainly caused by modal resonance. If the modal characteristics of the entire vehicle, equipment, and turnstile are not properly matched, abnormal vibrations and noise may occur in the rail vehicles. Therefore, it is necessary to conduct modal analysis and mistuning design of subway vehicle turnstiles to ensure smooth operation, reduce structural vibrations and noise, and improve the safety and ride comfort of the vehicles. By adopting a modal identification method for vehicle turnstile under operating environmental excitation, the modal parameters of the turnstile structure before and after wheel profiling and under different loading conditions were identified. According to the test results, it can be concluded that wheel profiling has little effect on the modal parameters of the structure, but as the load increases, the modal frequencies of various orders generally increase. This is related to the increase in the stiffness of the turnstile air spring due to the increased boundary constraints caused by the increased load. By comparing the test results with the simulation analysis results of the turnstile structure under free and constrained states, it is found that it is necessary to simulate the actual boundary constraint conditions as much as possible to ensure the accuracy of the finite element model. This provides a basis for subsequent researchers to study modal mistuning design.
1
Study on Risk Control of Shield Undercrossing Operation Station in Water-rich Soft Stratum

wuxinliu

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In order to reduce the disturbance to the existing metro station caused by shield tunneling in water-rich soft stratum, taking the construction of a T-type transfer station with shield tunneling passing through the operation station as the engineering background, the cutter configuration and tunneling parameters of the shield tunneling cutting the diaphragm wall without glass fiber reinforcement are studied by theoretical analysis and field measurement, and the key risk control measures of the shield tunneling passing through the operation station are proposed. The results show that the shield can pass through the diaphragm wall safely by using high strength shell cutters with different cutter heights, reducing the tunneling speed and thrust of the shield, and increasing the torque of the cutter head, and that the disturbance to the floor can be reduced by taking the interaction force between the floor of the operation station and the stratum as the additional load during the construction of the underpass and taking the static soil pressure at the center of the shield increasing by 1.2 times as the set value of the chamber pressure; The settlement of the existing structure can be well controlled by filling the gap between the shield shell and the stratum with clay shock, and filling the building gap behind the segment with the combination of synchronous grouting, secondary grouting and radial grouting; The deformation caused by the construction of shield undercrossing operation station is mainly settlement. The deformation caused by the construction of shield cutting diaphragm wall is mainly horizontal displacement, accounting for more than 75% of the total horizontal displacement.
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Analysis of Travel Speed and Speed Efficiency of Existing Urban Rail Transit Lines in China

gaoguofei, yangyunze, yanyana, dugangde, tongxin

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In order to measure the efficiency of travel speed of urban rail transit lines, the concept of speed efficiency is introduced. Based on the operating data of 170 urban rail transit lines in my country, it covers the fully closed-operated subway, light rail, monorail system, etc., only considering the train operating mode of the station parking, from the average station spacing and line design speed to travel speed and travel speed and travel speed and travel speed and travel speed and travel speed and travel speed and travel speed and speed of travel. The speed efficiency is analyzed, and the results show that most lines (about 64%) design speed is 80km/h, and the average station spacing is between 1.0~2.5km, of which 89.9% of the line travel speed is distributed at 30~40km/h, the speed is The efficiency is distributed at 37.5~50.0%. In addition, quantitative analysis of changes in travel speed and average station spacing, design speed correlation, and changes that are correlated with the average station spacing positive and negatively related to the design speed. Finally, based on the fitted travel speed and speed efficiency formulas based on actual data, the corresponding distribution relationships of average station spacing, design speed, travel speed and speed efficiency were calculated, which can provide reference for measuring the reasonable range of travel speed and speed efficiency of urban rail transit lines.
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Research on the Necessity of Rail Transit Lines 26/27 Interconnection Between Chongqing Core Hubs

SHI Xiulu

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In order to prove the necessity and rationality of interconnection with Chongqing rail transit Line 26 and Line 27 based on the connotation of urban rail transit interconnection, this paper summarizes the macro positioning of planning fit, improving service quality, guiding urban development and implementing resource sharing. And it analyzes the economic benefits, operating losses and civil investment increase caused by the interconnection mode. With the influence of time value, the converted net present is used as the measurement index of the interconnection’s necessity and rationality to demonstrate Line 26 and Line 27. The results show that the converted net present of interconnection with Chongqing rail transit Line 26 and Line 27 is greater than zero. The necessity of interconnection is prominent and the scheme is reasonable, which should be recommended. In view of the necessity of urban rail transit interconnection, this paper constructs an analytical framework combining qualitative analysis and quantitative analysis, improves the research system of urban rail transit interconnection, and provides an effective reference for the planning and design of similar projects.
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Research on the bridge-rail interaction of small radius curved bridge and effect of fastener resistance under temperature effect

QIAO Hong, HUANG Chengying, WANG Shaoqin, DAI Zuhao, RUAN Liangfeng, DU Xianting

Abstract: (99) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

To study the temperature effect on the bridge-rail interaction of small radius curved bridges, with a curved tram bridge taken as engineering background, an integrated rail-bridge-pier spatial finite element model considering continuous welded rail was established and verified. The bridge-rail interaction law of the straight bridge and the small-radius curved bridge was analyzed and compared, and the magnitude and distribution patterns of additional expansion force of rail, lateral force at bridge pier top and longitudinal force at bridge pier top of the small-radius curved bridge under the overall heating conditions and local heating conditions were compared and analyzed, based on which three fastener arrangement schemes were proposed and compared. The research results indicate that under the overall heating condition, on small radius curved bridges, the lateral displacement of the steel rail and the lateral force at bridge pier top are larger than those of the straight bridge. Under the overall heating condition, as the bridge temperature increases, the additional expansion force of rail gradually increases. The expansion force of the rail and the longitudinal force on the top of the pier when the overall heating condition is used for calculation are larger than those with the local heating condition used for calculation. Compared to constant resistance fasteners, small resistance fasteners can significantly reduce the additional expansion force of rail, but too small longitudinal resistance can easily lead to large fracture joints when the rail breaks. The results of the study provide a reference for the design of continuous welded rail on small radius curved bridges for trams.
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Distribution of particulate matter in subway and prevention and control measures

Meng Xin, 毛海和

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To investigate the sources and distribution patterns of PM2.5, PM10, and TSP particles in subway stations, this paper conducted a particulate matter concentration detection in 11 stations along two subway lines in a certain city. The testing areas encompassed outdoors, public areas of stations, equipment management rooms, and corridors inside the platform end doors. Particulate matter concentrations of PM2.5, PM10, and TSP were measured in each area, and samples of particles were collected from both outside the station and on the platform. Elemental analysis of the particulate matter was conducted, and further analysis was performed to investigate the distribution of PM2.5, PM10, and TSP particles in different outdoor concentration levels in each area. The results of the particulate matter composition analysis revealed a significant increase in iron content in the particles within the subway stations compared to those outside. The iron-containing particles inside the subway stations often exhibited flaky and irregular shapes, differing from those outside. This indicates that the primary source of particulate matter is friction between wheels and rails. Analysis of the concentration measurements in various areas revealed that when outdoor particulate matter concentrations are low, the distribution patterns of particles of different sizes are similar, with the overall trend being higher concentrations inside the tunnels than inside the stations and outdoors. However, when outdoor particulate matter concentrations are high, PM2.5 and PM10 concentrations generally exhibit higher levels inside the tunnels than outdoors and inside the stations. Regardless of outdoor particulate matter concentration levels, TSP concentrations in public areas and train carriages are consistently higher than outdoors. Furthermore, based on the detection results, relevant suggestions for the prevention and control of particulate matter in subway stations are provided.
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Research and Application of Rail Transit Metro Vehicle Speed Measurement Platform Scheme

wu jun, wang junping

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At present, subway vehicles are equipped with various speed sensors from different systems, resulting in multiple sensor types and a large number of sensors. In response to the current development status and issues in vehicle speed measurement, a vehicle speed measurement platform is constructed to unify the speed sensor models, provide speed information to all systems, reduce the number of speed sensors, simplify the underframe wiring, and lower the cost of maintenance and operation. The vehicle speed measurement platform integrates speed sensor and accelerometer information to provide more accurate speed data; combined with ground balise equipment, it provides more accurate wheel radius calibration values for all systems, enhancing the control accuracy and operational performance of the vehicles. The speed information can be transmitted via both hardwire and network, offering more flexible access methods for various systems. Field tests have verified that the speed information provided by the measurement platform meets the needs of all systems. A comparative analysis of the traditional speed measurement method and the measurement platform is conducted from five dimensions: system safety and reliability, system cost, system performance, vehicle installation and maintenance, and development trends. The vehicle speed measurement platform meets the needs of all systems and is in line with the development trend of integrated vehicle control design.
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Optimization of fire water supply control system in subway station

MU YuHong

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The purpose of this paper was to explore the optimization method of automatic pump start of fire water supply control system for municipal direct pressurized water supply in subway. By describing the development history of fire control pipe network and system control in subway stations, aiming at the problems such as non-action of pump start and too long time of station fire control system, field test and analysis of test data are adopted in subway stations, and the changing characteristics of fire control system pressure and flow are mastered through practice. The conclusion is drawn: The municipal water pressure affects the setting of the action value of the pressure switch. A new method for determining the values of pressure switch, flow switch and stabilizer pump set based on municipal water pressure threshold was established. Because the setting value of the pressure switch is affected by the municipal water pressure, the station municipal direct pumping fire control system should adopt high pressure regulation. It is found that the pressure switch and flow switch are complementary under different working conditions, so the flow switch and pressure switch are set as automatic pump start function to improve the reliability of automatic pump start. The logical relationship between the action value of the pressure switch, the flow switch and the pressure regulator pump group should be adjusted according to the different setting schemes of the pump room, so as to avoid the risk of the pressure switch flow switch operating incorrectly to start the pump due to the leakage of the fire control pipe network, and to solve the problem that the automatic pump starting time is too long or too fast. To explore the fire control system optimization scheme in line with the characteristics of subway stations, and effectively improve the efficiency and safety of the subway fire water supply system.
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Analysis and Thinking on Digital Operation Developmentof Kunming Metro Line 4

HE Xiong

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The high-speed development of urban rail transit has brought unprecedented challenges to enterprise operation and management, and the traditional operation method restricts the use of data and resource sharing. With the rapid advancement of the strategy of a strong transportation country and the construction of smart cities, the subway, as an important part of the residents' transportation and travel, the contradiction between the high operating costs and the mismatch of traditional operation and management means, urgently needs to change from traditional thinking to digital thinking, to digitally drive the quality of operation and management, and to improve the efficiency of enterprise production. This paper summarizes and analyzes the difficulties of digital operation of rail transportation, and takes Kunming Metro Line 4 as a case study to show the path of digital transformation of Line 4 operation and the results of the economic benefits of digital operation.Line 4 realizes digital operation of the metro by building a comprehensive automation system and business integration management system for rail transportation based on the cloud platform and carrying out the change of digital transformation of the enterprise in a synchronized manner, in order to practically promote the digital operation of the metro. By building a comprehensive automation system and business integration management system based on the cloud platform and simultaneously carrying out enterprise digital transformation changes, Line 4 realizes digital operation of the metro, and promotes the cost reduction and efficiency of the enterprise with practice, and provides digital operation solutions for urban rail transit for the industry.
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Research on the Mechanical Method Construction Scheme for Ultra-long Connection Channels in the Composite formation Area

WEI Xupeng, FU Zeng, CHENG Peng, LI Peng, ZHANG Dongyan

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In order to avoid the problems of high risk and long construction period in the construction process of long-distance connection channels using conventional construction methods, it is planned to use the mechanical method for the first time in the composite formation of South China.Therefore, research was conducted on the overall plan, construction method selection, equipment selection, and segment structure design, and the project was successfully implemented under the guidance of the research results. And the following conclusion is drawn: the mechanical method of connecting channels can solve engineering problems with long distances, large angles, and large inclinations, and has applicability in composite formations in South China; It is feasible to change the assembly method of pipe segments from radial insertion to longitudinal insertion followed by radial insertion by modifying the pipe segment design scheme.
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Research on Key Problems of Real-time Optimization of Braking Performance of Urban Rail Transit Trains

YuKe, ZhangXuannan

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The train control system of urban rail transit is mostly based on fixed parameter algorithm, which has problems such as inaccurate braking and deviation of parking position in the face of environmental changes, thus increasing the risk of collision and directly threatening the safety of train operation and passenger comfort. Aiming at the shortage of real-time and accuracy of the existing automatic control system, an intelligent upgrade scheme of train control system is proposed. Firstly, an accurate train dynamics model is established by parameter fitting, and then a sliding mode adaptive robust control strategy is used to adjust the train control system in real time. Through the simulation of Beijing Metro Line 5, the braking performance index of the train model and the optimization algorithm of the on-board controller are calculated, and the optimization ratio of the parking accuracy reaches 91.36%. The results show that the proposed optimization measures are effective in improving braking performance and have important application value and practical significance in urban rail transit system.
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Experimental study on smoke control of tunnel fire for cancelling fire door in the cross-passageway

WANG yiran, CHEN yafei, LI yanfeng, LI lei, XIA sanxian, ZHANG xiaowei, ZHU lan

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In response to the lack of experimental verification for the smoke control and ventilation models in tunnel fires without fire doors in the cross-passageway of urban rail transit projects, this study conducted a multi-condition ventilation and smoke control experiment on a typical tunnel of Zhengzhou Metro. The experiment focused on different locations of train fires within the tunnel. By testing the smoke control wind speeds in both the fire tunnel and cross-passageway under different conditions, we aimed to verify the impact of not installing fire doors in cross-passageway on tunnel fire ventilation and smoke control, as well as evaluate the effectiveness of different ventilation and smoke control models. The results showed that for stations with fully enclosed platform doors and one cross-passageway in test section tunnels, when no fire doors were installed (i.e., with open fire doors), all tested ventilation and smoke control models achieved wind speeds greater than 2m/s blowing towards the side where the fire occurred at door openings. At the same time, exhaust wind speeds inside the fire tunnels also exceeded 2m/s, meeting relevant regulations" requirements for smoke control. It is feasible to cancel fire doors in similar projects. Different ventilation and smoke control models yielded varying wind speeds at door openings. Models using two tunnel fans supplying air to the fire tunnel and pressurizing non-fire tunnels along with four exhaust fans extracting smoke from the fire tunnel achieved higher wind speeds at cross-passageway entrances.
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The construction characteristics of the Japanese station square and its inspiration for China.

MA Fei, OTA Mitsuru, XU Chang

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With the continuous development of rail transit and urbanization in China, the single-function station square planning can no longer meet the current diverse urban construction needs. This study combed the construction history and related planning standards of station squares in Japan, conducted on-site research on station squares in multiple cities of different levels, analyzed the spatial planning and development methods of representative cases, and summarized the conclusions of Japanese station squares. planning experience: Pay attention to the spatial regulating role of the station square in the integrated development of the station and city, and adjust the urban function of the square according to planning needs; the construction of the square should be combined with the development characteristics of the surrounding areas of the station, focusing on the flexible layout and diversified use of the square; planning A cooperative organization will be established at each stage to focus on mutual communication and division of responsibilities among the various construction departments of the square, as well as the development of a continuous user participation mechanism and a complete square operation system, etc., thereby hoping to provide reference and guidance for the sustainable development of China's rail transit and reasonable urban space planning.
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Simulation and energy saving analysis of various new urban rail traction power supply systems

LIU Mingliang, TIAN Zhongbei, DONG Hongzhi, ZHENG Junfeng, ZHU Dongpo, CHEN Lei

Abstract: (103) HTML (0) PDF (0.00 ByteKB) (0)

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From the angle of energy-saving and emission-reduction, this paper studies energy-saving methods and strategies to reduce the energy consumption of urban rail transit. Based on the traditional method of power flow calculation, the equivalent circuit model of traction power supply system for urban rail transit is established. Combined with data analysis of Hefei rail transit line 1, a multi-train operation simulation was conducted using a new urban traction computing simulation model, the energy consumption of traction substation in the existing traction power supply system and three new traction power supply systems (inverter feedback, energy storage, photovoltaic) is analyzed. The results show that compared with the existing traction power supply system, the traction power supply system with inverter feedback can significantly reduce the energy consumption of traction substations, traction power supply system with energy storage system can effectively reduce the peak power of traction substation, traction power supply system with photovoltaic system can reduce up to 24.89% of the traction substation energy consumption.
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Exploring the Identification and Evolution of Key Stations in Urban Rail Networks using Singular Value Decomposition

Wang Yizhe, Qiu Yuzhi, Wang Zijia

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In order to identify key stations in urban rail transit networks and study their evolution over multiple years, we construct a key station recognition method based on truncated singular value decomposition (TSVD). OD data during the morning peak hours from 2011 to 2019 in Beijing are selected as the dataset. The analysis of network passenger flow evolution and identification of key stations in subway networks are conducted using the indicator of key eigenvectors and compared with the identification results obtained from complex network methods. The analysis demonstrates that, TSVD can be effectively applied to identify key network stations considering OD distribution, and the resulting identification outcomes to some extent better represent the spatial distribution of network passenger flow. In terms of application results, it is discovered that the spatial layout of key stations in Beijing's urban rail transit tends to develop towards multiple centers, such as the Northwest Xi'erqi, as well as the Southwest Fengtai Science Park. These stations gradually form network passenger flow centers and establish connections with each other. Stations like Southeast Tu Qiao and Northeast Fengbo also exhibit a preliminary trend towards becoming network passenger flow centers.
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Research and Design of Intelligent Judgment Mode for Urban Rail Transit Security Inspection System

XIONG Xiaofeng, jinzhaoyuan

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In order to improve the efficiency and accuracy of urban rail transit security inspection system, this paper designs a novel pattern recognition mode to effectively combine AI ( artificial intelligence ) image recognition technology with manual centralized pattern recognition technology.Firstly, according to the current situation of liquid inspection, the liquid detection algorithm is introduced to avoid the open inspection of safe liquid. Secondly, the security products are classified according to the risk level. Finally, the AI confidence judgment, manual sampling or necessary inspection chart are combined to determine.The pattern recognition mode can flexibly adjust the depth of AI intervention according to the accuracy of AI image recognition and the needs of pattern recognition at different stages. With the continuous improvement of the accuracy of AI image recognition, it gradually changes from AI-assisted manual-based pattern recognition mode to AI-based manual-assisted pattern recognition mode, and finally realizes the fully intelligent pattern recognition mode.Through case analysis, it can be seen that the judgment graph model can further achieve the effect of rapid security inspection, cost reduction and efficiency increase without reducing the safety inspection level of urban rail transit stations.
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Analysis on vibration effect of immersed floating slab track based on fluid-solid coupling

LU Ruiquan, YANG Lin, YUAN Dehao, NIU Xiaoli

Abstract: (108) HTML (0) PDF (0.00 ByteKB) (0)

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A numerical model of immersed steel spring floating slab track vibration based on fluid-solid coupling theory was established. The vibration reduction of the floating slab track with different accumulation water depth under train running considering track, water and tunnel base was analyzed. The results show that the water under the floating slab can influence its performance of vibration reduction. When the depth of the accumulation water was lower than the 1/2 height of the slab side space, the effect on the vertical vibration of rail and slab was small but on the vibration of tunnel was obvious which would increased about 5dB on vertical vibration level. When the water filled with the entire height of the slab side space, the vertical vibration of rail and slab was reduced while the vertical vibration level of the tunnel at its peak value frequency increased about 13.4dB (30.7%). The insertion loss of the tunnel vibration level also increased about 13.36dB and 13.67dB at 63Hz and 80Hz respectively. Therefore, when the height of the water under the floating slab was over the 1/2 height of the slab side space, which means the vertical vibrations of the slab and tunnel at their peak value frequency were larger of 5dB and 10dB respectively than the normal condition without water, the maintenance work to drain away the water should be carried on immediately.
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Tianjin Metro Emergency Dispatching Command Platform Plan for Integrated Demand and Intelligent Trend

CHEN Xu, ZENG Xiaoxu, LIU Ying, ZHAO Zhanyun, GAO Fan

Abstract: (105) HTML (0) PDF (0.00 ByteKB) (0)

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The urban rail transit dispatching and command work is a complex system engineering, and the emergency dispatching and command system, as the top priority of the urban rail transit dispatching and command work, directly affects the level of enterprise operation service and train operation safety. Taking the Tianjin Metro emergency dispatch as an example, this paper summarized the basic modes of emergency dispatch and command in domestic urban rail transit, and combined the trend of information integration and intelligent operation of urban rail transit. The overall goals and functional requirements of the Tianjin Metro emergency dispatch and command platform were proposed, and a Tianjin Metro emergency dispatch and command system architecture and technical solution oriented towards integration and intelligent trend were established, thus providing support for the safe and orderly operation and scheduling of subways under networked conditions.
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Key Technology Study for Automatic Generation of Rail Transit Pipe Fittings

Yin Dixian, Deng Xueyuan, Lu Kun

Abstract: (116) HTML (0) PDF (0.00 ByteKB) (0)

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Focusing on the complexity of urban rail transit pipelines and the difficulty that the generation of pipeline 3D models still relies on human-computer interaction, this paper proposes a method to automatically generate parametric pipe fittings. The method automatically judges the types of elbows, tees, crosses and other fittings according to the straight pipe centerline data extracted from drawings; calculates relevant parameters; expresses models by using IFC; and uses C++ to realize the automatic generation of models, which is proved to significantly improve the efficiency of pipeline model generation and the degree of automation.
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Analysis and Design of Track Panel Well in Overlapping Subway Tunnel

Li Yueyang, Du Yufeng, 刘飞, Wang Weifeng, Li Zhe, Jin Tianrui

Abstract: (131) HTML (0) PDF (0.00 ByteKB) (0)

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In order to meet the lifting requirements of the track bed in the subway design, it is necessary to set the track panel well hole (28m×5m) in the roof and middle plate of the open-cut station or the open-cut section. The large opening of the track panel well seriously weakens the stiffness of the plate, and the traditional two-dimensional frame section calculation under the construction condition cannot meet the design requirements and the actual situation. In addition, it is very important to choose the supporting structure of the track panel well section, which is closely related to safety and economy. Based on a specific case of the design of a stacked subway track panel well in the high water pressure fine particle stratum in the east of Beijing, this paper introduces the comparison and selection ideas of the project envelope and main structure, and the key problems of structural calculation, hoping to provide reference for the design of track panel well in the future process of subway construction.
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The development and applicability analysis of medium and low volume rail transit system in the world

HE Peng, LIU Penghui, LI Songsong, LIANG Qinghuai

Abstract: (234) HTML (0) PDF (0.00 ByteKB) (0)

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As the encryption and supplement of the metro network in super megacities and the backbone of medium-sized cities and even big cities, medium and low volume rail transit plays an important role in solving urban traffic problems. Based on the survey of more than 2600 medium and low volume rail transit lines in 496 cities in 65 countries, the database of medium and low volume rail transit lines in the world is constructed. Based on the database, this paper analyzes the distribution of nine medium and low volume rail transit systems, including gear rail, tram, suspension monorail, APM, straddle monorail, linear motor system, medium and low speed maglev, electronic guidance rubber-tyred system and beam-guiding rubber-tyred system in different continents, countries and cities. And the statistical analysis of each system in different countries, different city characteristics, different line function positioning. At the same time, the origin and development of each system are summarized, and the technical characteristics, parameters and applicability of each system are analyzed. The research results can provide reference for the choice of urban medium and low volume rail transit system in our country.
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Research on the key technology of track seamless in the development depot based on the upper cover of vibration source control

Zhang Dong feng, Shao Zhuang

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In view of the urgent need for vibration and noise reduction in the upper cover development, this paper summarizes the existing control measures of track vibration and noise in the depot, puts forward the necessity of seamless rail in the depot line, and studies the demand for sleepers. After calculation, it is believed that the depot can meet the strength and stability requirements of the seamless line under the condition of using the arm span resistance pillow and cooperating with other strengthening measures. Furthermore, this paper proposes the seamless turnout technology of No. 7 movable turnouts, and carries out the seamless verification of the turnouts in combination with the actual use conditions in Beijing, and it is believed that the turnouts and the turnouts group have the conditions for seamlessness. Under the condition of 15km/h, this paper conducts a comparative test, and it is believed that the movable turnout has a vibration and noise reduction effect of 3~5dB compared with the fixed turnout.
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Improved prediction model of metro wheel wear based on BiLSTM network

Zhu Aihua, Bai Yang, Bai Tangbo, Wang Yali, Zhang CaiSheng, Li Anyan

Abstract: (104) HTML (0) PDF (0.00 ByteKB) (0)

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In order to address the issue of long-term dependence caused by the extended time span of wheel wear data and improve the prediction accuracy, this paper an improved BiLSTM metro wheel wear prediction model is proposed by optimizing Bidirectional Long short-term memory network (Bi-LSTM) with Sparrow search algorithm (SSA). Firstly, the hyperparameters of the Bi-LSTM algorithm, such as the number of neurons, iteration count, input batch size, and learning rate, are optimized using the SSA. This optimization process is conducted within a specified range to obtain the optimal values of these hyperparameters. This optimization process aims to obtain the optimal parameter values. Subsequently, the SSA-BiLSTM network model is constructed using these optimal parameter values to predict and analyze wheel wear. Tread wear and flange wear are taken as the research objects, and the measured historical wear data of wheel No.1 of the metro’s carriage # 1 are used as inputs to metro and validate the model, and compare the prediction results with those of MLP, LSTM, BiLSTM and SSA-LSTM models. The results show that the improved bidirectional long short-term memory network model has higher wear prediction accuracy, and the mean absolute percentage error (MAPE) of tread wear is reduced by 13.28%, 10.32%, and 1.47%, and flange wear by 9.5%, 0.46%, and 0.02%, respectively, and the model"s excellent generalization ability was verified by comparing it with the wear data of the first wheel of the same metro trains 2 and 4. The results confirmed that the model exhibits strong generalization capabilities. The wheel wear prediction model with improved BiLSTM network proposed in this paper can effectively improve the prediction accuracy, providing theoretical support for intelligent management of metro wheelsets and extending the wheel"s lifespan.
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Use of shield muck for producing grouting material and its application in stacked tunnels

ZHOU Yanjia, YANG Guohua, WANG wei, LI Wentao

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Focusing on the reuse of tunnel muck, this article aims to prepare tunnel muck from Suzhou Metro Line 8 into synchronous grouting material that meets the engineering requirements for different geological conditions by adjusting solidification material compositions through laboratory experiment. In this project, a new double-line shield tunnel of Metro Line 8 intersects with the existing double-line tunnel of Line 3 at Tangzhuang Station, forming a unique situation with two layers of four tracks. The muck-produced grout used in this project have a consistency value of 113 mm, and the 7-day and 28-day strengths exceed 1 and 2.5 MPa, respectively, meeting the engineering specifications. Based on the deformation monitoring data, it is evident that the muck-produced grout effectively controls the impact of upper tunnel construction on existing structures. Utilizing shield tunneling muck to prepare synchronous grouting slurry can achieve the resource utilization of muck, while promoting green construction and reducing the construction cost of around 750 thousand Yuan per kilometer (double line).
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Analysis of Escape Risk and Braking Strategy for Commuter Trains under Rescue Treatment

ZHU Kan

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With the vigorous development of urban railways, the rescue scenarios during their operation urgently need to be analyzed. The "public transportation operation mode" of urban trains results in shorter running times, as same as to subway rail trains, which requires higher timeliness for rescue than high-speed trains. However, the capacity of urban trains cannot fully meet the above operational needs. This article establishes a longitudinal dynamic model for multi-formation train coupling, and Beijing New Airport Line was token as an example to analyze the potential risk of train slip caused by the existing urban rail transit operation under rescue scenario The results show that when coupled on the maximum slope, the train will slip and generate a high impact rate, which will reduce passenger comfort. When parking on a slope, the brief loss of train braking force also poses a risk of slipping due to the brake-traction switching process. At the same time, the comfort of passengers during the rescue process was analyzed, and the results showed that when the coupling speed reached 4km/h, the comfort of passengers significantly decreased, exceeding the limit. A speed limit for commuter train rescue coupling based on actual operation was developed, as well as a holding braking mode under rescue treatment to meet the safety and comfort of the passengers.
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Numerical and Experimental Studies of the Dynamic Coefficient of the U-shaped girder for Urban Rail Transit

潘艳阳, Xia Chaoyi

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The mechanic behaviors of the U-shaped girders in urban rail transit are different in the spanning and transverse directions, and the dynamic coefficient of 1.40 in the current design code will lead to material waste. Considering the bidirectional stressing characteristics, the U-shaped girder of the Nanjing S6 Urban Rail Transit is selected as the study case, and the train-bridge coupling dynamic model is established. By comparing the tested and calculated results, the model effectiveness is verified. Through the studies changing the train speed and the train formation, the dynamic coefficients of different responses are analyzed. The results indicate the girder bottom only bears longitudinal tensile stress, but it carries both of transverse tensile and compressive stress at the same section. The maximum dynamic coefficients of the deflection, the longitudinal stress, and the lateral stress are 1.231, 1.216, and 1.362 respectively, which occur at the full and fixed loaded cases of the 6-car formation. When determining the dynamic coefficients of a single-track U-shaped girder, the influence of train formation should be considered, and the values should be distinguished according to the stressing directions. It is recommended to take 1.30 when calculating the deflection and the longitudinal stress, and to remain 1.40 when calculating the lateral stress. The study is to propose the reasonable values for the dynamic coefficients of the U-shaped girders, and provide reference for the structural optimization.
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Cooperative passenger flow control method of urban rail transit based on reinforcement learning

WANG Dianyuan, ZHAO Xingdong, DOU Fei, ZHOU Xu

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The rapid urbanization and population increase have led to a continuous rise in passenger flow in urban rail transit, which presents significant challenges to the safety, comfort, and stability of rail transit operation. In order to solve the problem of excessive load rate of urban rail transit during peak hours, we propose a cooperative passenger flow control method for urban rail transit, which is based on deep reinforcement learning. This method uses the full load rate between intervals as its state, the flow restriction strategy as its action, and the passenger flow experience as its reward. Then, it generates the optimal flow restriction scheme through multi-round reinforcement learning training. Subsequently, we validate the effectiveness of this method by constructing simulation experiments using the Beijing subway network data. The simulation results show that the cooperative passenger flow control method can effectively reduce the passenger flow in the section, relieve the congestion in the peak hour section, and improve the passenger travel comfort.
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Overall strategy of comprehensive development of TOD of rail transit stations based on top-level design -- Taking Foshan as an example

LIU Erhui, XIE Zhiming, XU Shiwei, SU Yehui

Abstract: (159) HTML (0) PDF (0.00 ByteKB) (0)

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For improving the comprehensive development efficiency of land along rail transit lines, guiding the orderly development of urban rail transit stations and ensuring the supporting role of urban sustainable development, the innovative research on the overall strategy of TOD comprehensive development in Foshan based on top-level design was conducted. Firstly, sorting out the practical problems faced by Foshan City, as an important mega city in the Guangdong Hong Kong Macao Greater Bay Area, in the current stage of comprehensive development of rail transit, such as the lack of interest sharing mechanisms, failure to collect and store land along the line in advance, insufficient planning and coordination of station site selection, and mismatched timing between rail construction and comprehensive development; Then, a comprehensive coordination framework for reasonable development and propose development strategies such as improving top-level design, strengthening strategic coordination, advancing land preparation and storage, and exploring diversified land supply was established. Finally, taking the land use planning practice along the second phase of urban rail transit construction planning in Foshan City (Line 4 Phase I, Line 2 Phase II, and Line 11) as an example, top-level policy issues, top-level planning issues (coordination of national spatial planning and comprehensive transportation planning), land issues (land preparation and storage, diversified land supply mode issues), and TOD construction mode issues were discussed, it explored and established a top-level design practice path for comprehensive development that is in line with the characteristics of Foshan City, it proposed a TOD comprehensive development overall strategy that is suitable for the actual situation of Foshan City, effectively guided the implementation of comprehensive development of land around stations along the line, and provided valuable top-level design practice experience and reference basis for similar metropolitan areas.
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Construction technology of underground tube jacking subway station based on structure division method

FU Zeng, FAN Xiaodong, WEI Xupeng, LI Peng, YU Changyi

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In order to avoid many negative problems caused by the traditional open-cut method of subway station construction, such as blocking, demolition of shops, underground pipeline relocation, etc., the construction technology of rectangular tube jacking underground subway station is studied based on the engineering background of Haibang Station of Guangzhou Metro Line 3 East extension. First of all, three kinds of pipe jacking combination schemes are proposed, and the characteristics of the three schemes are summarized, and the scheme selection is made according to the actual station engineering. Then, the section design, pipe jacking machine selection, pipe section design and waterproof design of the station are introduced. Finally, the feasibility of the combined pipe jacking method is verified by theoretical calculation and numerical simulation. The results show that the rectangular tube jacking underground subway station construction technology can be used in the subway station construction of underground pipeline, and it is safe and can be implemented.
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Application Practice of e-CNY Hardware Wallet Currency in Suzhou Rail Transit

付保明, 张宁, 何铁军, 张炳森

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In response to the application issues of e-CNY hardware wallet in rail transit gate boarding, business process design and ticketing system transformation methods were adopted to achieve e-CNY hardware wallet in Suzhou rail transit gate boarding business. Firstly, the basic concept of e-CNY hardware wallet was introduced, and the application forms of e-CNY hardware wallet in rail transit were clarified; Then, taking into account the current business situation, usage needs, and technical characteristics of e-CNY hardware wallet in rail transit, the overall plan for passing through the gates and boarding the train with e-CNY hardware wallet is determined, and detailed design is carried out for the registration, entry and exit, ticket processing, and other business processes of e-CNY hardware wallet; Finally, combined with the current situation of Suzhou Rail Transit ticketing system, the specific transformation scheme of the Internet ticketing system and the AFC system is proposed, so as to realize the e-CNY hardware wallet lock-in service. The application of e-CNY hardware wallet in Suzhou Rail Transit has an important promotion significance for the promotion of e-CNY hardware wallet, and has an important reference value for the application of e-CNY in the field of rail transit.
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Research on Barrier Free Multipath Ticket Prices for Cross System Rail Transit in Urban Circles

zhangsen

Abstract: (92) HTML (0) PDF (0.00 ByteKB) (0)

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In response to the integrated fare system for cross standard rail transit payment areas in urban areas, Based on previous literature research and domestic and international research, this article,This article first clarifies the principle of cross standard barrier free ticket pricing under a single path,then, the multi-path cross standard barrier free ticket pricing schemes are divided into two categories: OD differential pricing and OD equal pricing,The technical means of accurately tracking passengers based on the classification of ticket types used by passengers in OD pricing research, and obtaining infeasible conclusions;The OD same price study recommends the weighted path algorithm, which takes into account the revenue of revenue guarantee enterprises and the public welfare guarantee people's travel expenses. This paper proposes two algorithms, namely, the passenger flow weighted path and the average weighted path, and describes the calculation steps of the algorithm in detail, and verifies the feasibility of the algorithm through two examples of Guangzhou Metro,This study is the first in China and fills a gap in the country to a certain extent.
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Research On The Compilation and Review Of Public Safety Monograph Of The Preliminary Design Of Urban Mass Transit

MA Biao

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The public safety monograph of the preliminary design of urban mass transit plays an important role in scientific planning and design of safety precaution engineering from the source, effectively improving the ability of safety precaution in operation, preventing and defusing public safety risks, it is also an important carrier for Public Security Organ to intervene in the construction of urban rail transport engineering early. Based on the analysis of the public safety risk and the establishment of the security standards of urban rail transit, the paper proposes that the monograph should be compiled in the form of modularization, in accordance with anti-terrorism riot, Emergency Management and police support to set up three modules. The Provincial Public Security organ of the Planning District is responsible for organizing expert group to review the monograph and finally issuing a written review opinion, the main basis of the review is systematically sorted out from three aspects: laws, regulations, standards and policy requirements, through research and analysis, the whole process can be divided into five stages: Project Initiation, preliminary review, site review, review and completion of review. The research achievement has realized the standardization of the whole process, and provides the reference for the related province (City) to carry out this work scientifically.
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A Research Review of Slow Traffic System in Urban Rail Transit Station Areas：Based on Citespace Analysis

FU Dongxue, ZHANG Shengrui, HOU Quanhua, ZHAO Meng

Abstract: (227) HTML (0) PDF (0.00 ByteKB) (0)

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Optimizing the slow traffic system in urban rail transit stations has a positive effect on improving the operational efficiency of rail transit, upgrading the spatial quality of stations, and promoting the integration of stations and cities. To provide reference for the planning theory and practical research in this field in China, based on the literature related to slow traffic system in urban rail transit station area in WoS and CNKI core databases, and with the help of CiteSpace, a literature analysis tool, this paper outlines the time, country, discipline and journal distribution, analyzes the research development history, identifies the recent hot spots: synergy research of station and city, shared bicycle transfer research and accessibility research. In addition, this paper reviews the current progress of four key research directions: slow traffic accessibility, slow traffic environment, slow traffic transfer and slow traffic facility planning. Moreover, the following prospects are proposed for future research: subdividing research subjects to understand the needs of multiple groups of people; updating research methods to accurately predict station traffic; expanding the scope of research to focus on station renewal in old cities; broadening research horizons to deepen research on station-city synergy.
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Comparative Study on Energy-Saving Optimization Control Strategies of Ventilation and Air-Conditioning System

ZHANG Yunxia, SU Ziyi, LI Xiaofeng

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Aiming to advancing the energy conservation project of subway stations, this study concentrates on the optimization of control strategies of the ventilation and air-conditioning (VAC) system. In this study, Beijing, Shanghai and Guangzhou were selected as the representative city for the cold region, hot-summer cold-winter region and hot-summer warm-winter region, respectively. Besides, model for subway station with platform screen door system was established in Transient System Simulation Program (TRNSYS). The performances of the automation control and optimized timetable control were compared in terms of station environment, energy performance and renovation costs. Results show that both automation control and optimized timetable control can effectively improve the station air temperature during the cooling season, achieving similar station environment. For energy use, automatic control can reduce the annual energy consumption of the VAC system by 41%~49% compared to the current conventional timetable control, while optimized timetable control can decrease the annual energy use by 38%~48%. As for renovation costs, optimized timetable control merely requires the improvement of management without supplementing devices, while automatic control needs higher equipment and maintenance costs. Therefore, it is recommended to adopt optimized timetable control for subway stations to achieve energy-saving potentials.
1
Shi Weishi, Huang zuning,Shang Hui

shiweishi, 黄组宁, 商晖

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The switch machine is the core equipment of the signal system, with the largest maintenance volume, the strongest maintenance difficulty, and a wide range of equipment failures. With the rise of intelligent operation and maintenance research in the urban rail transit industry, the research on intelligent operation and maintenance of switch machines has attracted the attention of industry scholars, and is the foundation for achieving intelligent maintenance of urban rail signals and intelligent operation and maintenance production organization modes. This article summarizes the shortcomings of traditional microcomputer monitoring systems and proposes an intelligent operation and maintenance system based on the maintenance difficulties and pain points of switch machines in the industry. The system mainly includes critical state perception, intelligent fault diagnosis, critical state warning, and health assessment, and proposes specific implementation methods. The system has been successfully applied to Nanning Metro Lines 4 and 5, with significant benefits.
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Hazard Analysis Technology based on Scenario Fusion for Fully Automatic Operation System

XUE Weiqing, DING Yi, LI Yan, DING Yafei, HU Feiyan

Abstract: (111) HTML (0) PDF (0.00 ByteKB) (0)

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In order to improve the operation safety of fully automatic operation system (FAO) in urban rail transit, proposed a hazard analysis method of FAO system based on scenario composited from the perspective of FAO system operation and maintenance, identified the hazards and relevant hazard elements of equipment in normal, fault, emergency, rescue and other scenarios, and carried out hazard analysis, Finally, from the perspective of FAO system operation, put forward relevant safety requirements for each core system of FAO, operation and maintenance personnel, equipment interface and construction, and solves the limitation that function safety integrity level (SIL) cannot be allocated in the safety analysis of traditional function Failure Mode, Effects and Criticality Analysis (FMECA). It provides a reference of the hazard analysis and SIL allocation for the construction of subsequent FAO system lines.
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Research on microenvironment and thermal comfort of subway carriage occupants based on amplitude-flow fan

GAO Zhixin, HE Feng, ZHAO Jing, DIAO Lei

Abstract: (110) HTML (0) PDF (0.00 ByteKB) (0)

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The airflow performance of the amplitude flow fan in subway carriages directly affects the thermal comfort of passengers. Taking the B-type subway carriage passengers equipped with amplitude flow fans as the research object, using CFD software STAR-CCM+ and Stolwijk human physiological model, the effects of fan speed, disturbance field function, and supply air temperature on the microenvironment of different parts of the carriage passengers were analyzed through 7 different working conditions. At the same time, the DR Berkeley thermal comfort evaluation model was used to evaluate the human thermal comfort of the carriage passengers. The results showed that in 7 operating conditions, the temperature and velocity distribution inside the cabin were uniform at fan speed of 1400rpm, disturbance speed of 3.25rpm, and supply air temperature of 20 ℃. The thermal flow field in the passenger microenvironment was the best, and the thermal comfort was better at 0.766.
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Performance evaluation of disc cutters of EPB/TBM dual mode shield tunneling machine in full section hard rock strata

SUN Zhang, WANG Zhenhua, JIANG Yihui

Abstract: (100) HTML (0) PDF (0.00 ByteKB) (0)

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In order to improve the excavation efficiency of EPB/TBM dual-mode shield machine and reduce the wear of disc cutters, the performance of disc cutters was studied based on the Intercity Railway from Airport East Station to HuangMaBu Station, ShenZhen, where the full section hard rock strata from ZDK8+583 to ZDK8+359.8 on the left side of the tunnel has been selected as the research target. First, the conditions of cutters replacement and wear were analyzed according to the different functions and types of disc cutters, and the optimum performance of disc cutters was obtained. The results indicate that China Railway's wide blade disc cutter is more suitable for excavation in this type of formation. In addition, in order to better guide the replacement of disc cutters, the service life of the optimum performance disc cutter was evaluated, and the tool information management system was established according to the actual situation. Through this system, information management of cutters can be achieved, ensuring more economical and efficient on-site construction. The above research can provide guidance for the selection of disc cutters of shield tunneling machine, and is conducive to strengthening the information management of disc cutters, promoting shield construction safer and more efficient.
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Statistical Analysis of Urban Rail Transit Operation in theWorld in 2023: A Review

HAN BAOMING, YU YIRAN, XI ZHE, SUN YAJIE, LU FANG, LI SIWEI, LI ZHUOYI, HUANG SIQI, HU JIANGFENG, SANG YANLING

Abstract: (1709) HTML (0) PDF (0.00 ByteKB) (0)

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With reference to the more common statistical standards in the international arena, urban rail transit is divided into three major categories, namely metro, light rail and tram, and the current status of the world"s urban rail transit operation is statistically analyzed. The analysis shows that by the end of 2023, 563 cities in 79 countries and regions around the world have opened urban rail transit systems, with a total mileage of more than 43,400.40 km, of which subways, light rails, and streetcars each account for 50.07%, 10.69%, and 39.24%. As of December 31, 2023, 66 cities in China (including Hong Kong, Macao and Taiwan) have opened and operated rail transit, with an operating mileage of 11,900.29 km, of which the operating mileage in Mainland China is 11,232.65 km. In 2022, the metros of 183 cities in 59 countries around the world transported a total of 58,652 million passengers, with an average load intensity of 0.81 million (passengers/day). kilometers), of which China (including Hong Kong, Macao and Taiwan) metro annual passenger traffic is 21.251 billion. China"s urban rail transit continues to develop steadily, and the scale of line network and passenger flow continues to rank first in the world. By analyzing the data after the release of Document 52 of the State Council, we forecast that low-capacity urban rail transit systems, such as streetcars, will flourish in mainland China, especially in the central and western regions, in order to promote green and sustainable urban development. Meanwhile, based on data from major countries (regions) and cities around the world before and after the epidemic, it is expected that passenger traffic in mainland China will return to pre-epidemic levels by 2024-2025.
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Contribution analysis of factors affecting magnetic induction voltage in subway based on BP-MIV

LIU Jiangtao, GAO Haiyang, WEI Ru, CHEN Tingji, YANG Lian, YAN Qiaona, KONG Weijun

Abstract: (118) HTML (0) PDF (0.00 ByteKB) (0)

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Metro traction current changes dynamically in train operation, resulting in magnetic induced voltage in the peripheral grid circuit, and the resulting induced current is one of the key issues that cause transformers to undergo DC demagnetization. The generation of magnetic induction voltage is affected by a variety of factors, in order to quantitatively analyze the size of the contribution of different influencing factors, this paper firstly uses the magnetic induction voltage formula to derive the main influencing factors of the magnetic induction voltage of the subway, and then establishes the "subway line-transmission line" magnetic coupling boundary element model to simulate and analyze the influence of the key factors on the induction voltage, and then analyzes the influence of the key factors on the induction voltage. In the stage of smooth running of the train, the induced voltage is affected very little, and at 1000m, the induced voltage has been attenuated by 90%, and then we constructed the back propagation (BP) neural network to generate the magnetic induced voltage, and analyzed the contribution of each influencing factor to the magnetic induced voltage by using mean impact value (MIV), which shows that the main influencing factors in the equivalent loop of the subway are the same as those in the grid, and the results show that the magnetic induced voltage in the equivalent loop is the same as that in the grid. The results show that the magnetic induction voltage in the equivalent loop is more likely to be influenced by the equivalent loop length, whose contribution is 44.38%, and the relative distance has the smallest contribution of 21.31%. Thus, it is the area of the power system constituting the equivalent loop that is the most important factor affecting the value of the magnetic induction voltage.
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Measurement and Analysis of Wheel-Rail Noise in Long-Span Bridges of Urban Rail Transit

shangting, zhonghao

Abstract: (116) HTML (0) PDF (0.00 ByteKB) (0)

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To investigate the wheel-rail noise characteristics of urban rail trains passing through long-span bridges, this study focused on the Dongshuimen Bridge of Chongqing Rail Transit Line 6 and the Chaotianmen Bridge of Chongqing Rail Transit Loop Line. Noise measurement data were collected during the passing the bridges. The study analyzed and compared the spectrum characteristics of the noise, summarizing the relevant patterns. The results indicate that the wheel-rail noise generated by rail trains on large-span bridges exhibits a wide-frequency characteristic, with the sound pressure level spectrum curve showing a “high in the middle, low on both sides” pattern. The noise peak of steel truss arch bridges is concentrated around 800Hz, and structural noise generates a relative peak in the range of 63-80 Hz. In contrast, the noise peak of steel truss girder cable-stayed bridges is in a higher frequency range. The three-span continuous steel truss suspension arch bridge exhibits a wide and high amplitude noise spectrum, with its noise being significantly greater than that of the steel truss girder cable-stayed bridge, especially in the mid-to-high-frequency range of wheel-rail noise.
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Overview of Subway Water Barrier Technologies and Devices at Home and Abroad

cheng ze nong, yang xin zheng

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In order to enhance the emergency response capability to subway waterlogging, this research investigated the water barrier technologies and devices for subways both domestically and internationally. Focusing on subway waterlogging risk points such as subway station entrances/exits, vent shafts, main tracks, and vehicle bases, a systematic review of conventional and innovative subway water barrier technologies and devices was conducted. Analyzed the advantages and disadvantages of various subway water barrier technologies and devices. This research discussed the challenges faced by subway water barrier technologies and devices in terms of cost economy, intelligence and automation, and sustainability. Recommendations were provided for structural optimization, material improvement, multifunctional water barrier devices, intelligent and automated control, green technology, and sustainable development. The research results indicate that different water barrier devices have different application scenarios. The water barrier devices should be selected by risk points and flood characteristics. Conventional subway water barrier devices are widely used and technologically mature. Compared to them, new technologies have advantages in automation, resource-saving, and improving emergency reliability. The research aims to serve as a reference for the design, installation, and application of subway water barrier devices, providing technical support for ensuring the safe operation of subway systems and effectively responding to subway waterlogging.
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Research on Rail Curve Superelevation Setting of Suburban Railway

lifengyu

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The paper studied the reasonable setting of suburban railway curve superelevation in the case of related specifications and standards that are not unified, and the principle of prioritizing the allowable values of each superelevation is not clear. By comparing and analyzing the requirements for curve superelevation setting in different codes and analyzing examples, this paper proposed the maximum and minimum values of design superelevation, the allowable values for under-superelevation and over-superelevation in general and difficult situations, and the allowable values for superelevation slope ratio which take into account such as the Code for Design of Railway Track, the Code for Design of Suburban Railway, and other industry standards, and the priority of design principles of allowable values for different superelevation was obtained, providing guidance for the setting of curve superelevation for new suburban railways, and providing reference for the improvement of industry related standards.
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Research on the construction of dual prevention mechanism in urban rail transit construction project

Lai Zhiwei

Abstract: (215) HTML (0) PDF (0.00 ByteKB) (0)

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The construction of dual prevention mechanism is an important work in the field of safety management of Urban Rail Transit projects. At this stage, there is a deficiency of the guidance for the construction of dual prevention mechanism due to the lack of laws and regulations, there are differences in the understanding and implementation of the dual prevention mechanism in various cities, and there also appear various problems in the executing process. Through the investigation and separation of the current situation of the construction of the dual prevention mechanism, it is concluded that the problems are mainly manifested in the mixing of phrases and terminologies the lack of safety risk management assessment, the incomplete investigation and rectification of hidden dangers, the inconsistent grading standards of hidden dangers, and the insufficient combination of risk and hidden danger controls. Relevant research can provide reference for the standardization and improvement of dual prevention and control in the field of Urban Rail Transit engineering construction
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Research on The Communication Machine Room Upgrade Scheme of Existing Subway Station Transfer Transformation

Liang Hai Ying, Wang yu jie

Abstract: (200) HTML (0) PDF (0.00 ByteKB) (0)

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With the continuous development of subway construction in China, the network operation mode of subway is formed, and more and more transfer nodes are formed. Due to planning and other reasons, the subway lines built earlier did not reserve late transfer access conditions. Therefore, in the process of new line construction, the transfer transformation and upgrading of existing stations are often accompanied by new stations. Among them, the transformation and upgrading of communication transmission system is one of the key work. Communication system is the traffic nerve of urban rail, which can be divided into public security communication system, civil communication system and special communication system. It supports the information exchange between the control center and stations and vehicles, and provides stable communication service for passengers. This paper discusses the communication room transformation and communication capacity expansion requirements brought about by the transformation of transfer stations under the operating conditions of existing lines, and proposes the enhanced MSTP construction scheme for public security transmission system and the backbone transmission system OTN construction scheme. Xitucheng Station of Beijing Metro Line 10 intersects with the newly built metro Changnan Line, and the changes in the building structure and function of the transfer station have put forward new requirements for the equipment systems deployment and equipment upgrade of the communication system. This paper applies the design scheme to the transfer project, verifying the rationality of the proposed scheme, and the research results provide an application reference scheme for the communication system upgrade of the transfer transformation of the existing station.
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Research on the Construction of a Digitized and Intelligent Subway Safety Emergency Assurance System

XU Xiwei, CHEN Wei, CHEN Guanlin, WANG Ying

Abstract: (147) HTML (0) PDF (0.00 ByteKB) (0)

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In the rapid development phase of urban rail transit, addressing issues such as inadequate emergency response and insufficient emergency handling in unexpected events, this paper presents the design of a digital twin-based subway safety and emergency assurance system. The system's design architecture, application scenarios, functionalities, and key technologies are elaborated upon. This system integrates diverse sources of data, including hydrological, meteorological, and sensor data, and utilizes emerging technologies such as digital twin, GIS, and BIM. It manages the entire emergency process of subway operation, encompassing daily safety monitoring, emergency resource management, emergency plan administration, and command and dispatch. Moreover, it focuses on enhancing capabilities for dealing with three major emergency scenarios: fire, typhoon and flood prevention, high passenger flow. This comprehensive development significantly enhances accident prevention, emergency response, and handling efficiency, while elevating the level of digitization and intelligence in the existing emergency management system.
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Research on carbon emission prediction and carbon reduction target of Xi 'an urban rail transit operation

WANG yiran

Abstract: (168) HTML (0) PDF (0.00 ByteKB) (0)

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In order to solve the problem of unclear carbon emissions from future operation and carbon reduction targets of the urban rail transit network, based on the statistical analysis of operational energy consumption of Xi 'an urban rail transit from 2018 to 2022, this paper uses the carbon emission factor method to calculate the carbon emissions from operation in the past five years. The energy consumption of Xi 'an urban rail transit in the next five years is predicted by the index method, and the carbon emission is predicted. According to the binding requirements of comprehensive energy consumption intensity proposed in the Action Plan for Green Urban Rail Development of China's Urban Rail Transit, the total energy saving target of Xi 'an urban rail transit operation in the next five years is quantitatively analyzed, and then the constraint value of total carbon emission and the target value of carbon reduction are determined. The research result indicates that approximately 174.9×104tCO2e total carbon emissions are generated during the operation of Xi'an urban rail transit from 2018 to 2022. In this condition, it is expected that 305.5×104tCO2e total carbon emission will approximately be generated during the next 5 years of operation, in which traction and station power consumption are the main sources of carbon emission. If the comprehensive energy intensity reduction target proposed by the association is achieved, compared with the predicted carbon emissions, the carbon emissions of the whole network are expected to be reduced by about 13% in 2025; the carbon emissions of the entire network are expected to be reduced by about 15% in 2027; In total, it is expected to reduce carbon emissions by about 10% over the next five years.
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Overview of urban rail transit operation lines in mainland China in 2023

HouXiufang

Abstract: (481) HTML (0) PDF (0.00 ByteKB) (0)

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By the end of 2023, a total of 28 provinces and 59 cities in mainland China had opened 338 urban rail transit lines, with a total scale of 11232.65km, including 8547.67km subway lines, accounting for 76.10%. At the end of the statistical period, 985.30km of FAO lines have been opened, accounting for 8.77% of the total mileage of lines in operation. In 2023, a total of 53 new urban rail transit operation lines (sections) were added, with a total length of 884.55km, including 539.50km new metro lines and 185.66km new FAO lines. The newly added operation lines involve 7 system systems, which are distributed in 30 cities, of which 3 cities will join the urban rail transit operation City camp. In 2023, the annual passenger volume created new historical records with the daily average passenger volume exceeded 80 million person times/day for the first time.
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Research on the Investment and Financing Mechanism for the Renovation of Existing Urban Rail Transit Lines in China

GUO Xuemeng, 李凯, MA Jiaxin

Abstract: (165) HTML (0) PDF (0.00 ByteKB) (0)

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China’s urban rail transport has now entered a new development stage of transformation from “incremental expansion” to “stock optimisation”, and the practical urgency of existing line reconstruction has given rise to a huge demand for funds, and at the same time put forward higher requirements for long-term sustainability of funds, so it is important to build an investment and financing mechanism suitable and matching the demand for existing line reconstruction to ensure the high-quality development of China’s urban rail transport. However, there are various types of existing line reconstruction and complex subjects of interest, but there is a lack of unified and complete guidance planning at the practical level, as well as an urgent need to provide sufficient research support for the innovation of investment and financing modes at the theoretical level. Therefore, this paper analyses the experience of typical cases in London, Japan, Beijing, Shanghai, Shenzhen and Tianjin. Based on the economic attributes, cyclical attributes, and multi-body characteristics of the projects, this paper explores the investment and financing system of grading and classification, and builds a mechanism that is synergistic with the financial subsidies and incentives, meanwhile integrates the stock of assets and new investment. This study can provide a reference and decision-making basis for improving the top-level design of existing line reconstruction, as well as forming a multi-principal synergistic investment and financing mechanism system for the medium and long term.
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Research on Station Design of Urban Rapid Transit

SHANLIN

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Urban rapidtransit emerges under the background of the development of urban circle in our country.This paper takes the Jingxiong Express Line as an example to explore the design standards of urban rapidtransit stations that can be popularized. It should have both advantages of railway and urban rail, and integrate with urban spatial pattern and urban comprehensive transportation system.In this paper, the characteristics and differences of traditional railway station and urban rail station are sorted out. Then, the paper analyzes the functional positioning of each station of Jingxiong Express line, which is divided into major urban traffic nodes, city level and regional level. In the face of the passengers' demand for rapid access to urban rapidtransit, public transportation operation is adopted to shorten travel time and provide efficient and convenient transfer and connection service level.In the face of the wind pressure generated by high-speed trains, full-height platform doors are set up to isolate the track area and the passenger waiting area, which can provide a comfortable waiting environment. Safe and reliable technical measures are taken to meet the requirements of wind pressure calculation intensity.In the face of the uncertainty of the development of the metro area, the station type selection and overall layout are the conditions for the future expansion of urban rail lines, the station type selection and overall layout are the conditions for the future expansion of urban rail lines.
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Identification of Risk Factors of Excavation based on TOPSIS Method

Liupeilu

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The complexity of deep excavation construction arises due to the influence of various potential risk factors on the construction procedure. In addressing this issue, this study introduces an intuitionistic fuzzy TOPSIS method aimed at identifying higher potential risk factors. Initially, potential risk factors are determined through an analysis of failure modes derived from prior excavation accidents, insights from practical engineering projects, and the expertise of engineering professionals. Subsequently, a risk evaluation hierarchy is established, and weights are assigned to experts and criteria using intuitionistic fuzzy numbers. To validate the proposed method's feasibility, a practical project associated with deep excavation is employed. The results indicate that the TOPSIS method effectively identifies high-risk factors. This developed method serves as a valuable decision-making tool for the safety risk analysis and control of excavation construction in similar engineering projects in the future.
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Quantum Computing Based Optimization for the Last-train Connection Planning Problem in Urban Rail Transit Networks

YUAN Ye, XV Hao, WANG Xi, WANG Zhenming, WEI Yan, XV Huizhang

Abstract: (148) HTML (0) PDF (0.00 ByteKB) (0)

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In recent years, there has been a rapid development in the process of urban rail transit networks construction in China. During the last train service period, the operational times of different rail lines vary, often causing passengers difficulties in successful transfers. Therefore, it has become an important issue to formulate a reasonable last-train connection scheme. Aiming at the optimization problem of last-train connection planning in urban rail transit network, this paper selects the arrival time of last trains as decision variables, and constructs a mixed-integer linear programming model to minimize the number of failed transfer passengers. To address the high model complexity caused by the expansion of network scale, firstly, the original model is reconstructed into a two-stage problem with smaller computation scale; subsequently, the first-stage optimization model is transformed into a QUBO (Quadratic Unconstrained Binary Optimization) model that can run on a quantum computer. The algorithm development and experimental testing are carried out based on the coherent Ising machine's optical quantum computing technology. To verify the effectiveness of the proposed method, this paper takes Beijing subway network as an example. Quantum computing results are compared with those from commercial solvers, confirming the feasibility of the model transformation method and quantum computing approach proposed in this paper. This provides technical support for the further application of quantum computing in solving complex optimization problems in the rail transit.
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Energy Saving Optimization of Train Interval Running Time Based on Dueling DQN Algorithm

LUI Fei, TANG FangHui, LIU Linting, HU Wenbin, HA Jinbing, QIAN Cheng

Abstract: (128) HTML (0) PDF (0.00 ByteKB) (0)

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Subway traction energy consumption can be reduced by optimizing subway timetable. In response to the impact of passenger flow fluctuations and train delays on the actual energy-saving rate, this paper proposes a Dueling Deep Q Network (Dueling DQN) deep reinforcement learning timetable optimize algorithm, combined with a real-time subway power supply current flow calculation model. An interval iterative optimization model based on the spatiotemporal distribution of dynamic passenger flow is established to suppressing the impact of passenger flow variation. Adaptive Moment Estimation (Adam) and root mean square propagation (RMSProp) methods are applied to predict the Q-network and target Q-network, to improve the model's convergence speed. While considering minimize the passenger transfer time and waiting time and total travel time， this model allows energy-saving timetable seamless switching. The test results of Suzhou Line 4 demonstrate the effectiveness of the proposed method. Under the condition that the arrival time deviation at transfer stations less than 2 seconds and the overall operating time of trains remains unchanged, the traction energy-saving 5.27%, and the train kilometer energy consumption decreases 4.99%.
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Simulation and Study of Shield Tunnelling based on Block-Based Discrete Element Method and Deformation of Surrounding Rock and liner

ZHOU Yuan, LYU Weifan, WANG Yingyi

Abstract: (105) HTML (0) PDF (0.00 ByteKB) (0)

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To address problems of numerical methods for continuous medium such as finite difference method and finite element method finite difference method and finite element method being unable to simulate the discrete medium characteristic of sandy cobble stratum, based on block-based Discrete Element Method, discrete element model is built to simulate the process of shield tunnelling through sandy cobble stratum, the displacement of joint plane and deformation of surrounding rock and liner is studied; and finite difference model, where sandy cobble stratum is transformed into equivalent continuous medium, is built to simulate the process of shield tunnelling, for the purpose of comparing the differences in numerical results between the discrete element model and the finite difference model. The results show that, in the discrete element model, the area where the positive normal displacement of the joints exceeds 0.1mm is mainly concentrated at the inverted arch, the area where the negative normal displacement of the joints exceeds 0.1mm is located at the hance, and the area where the shear displacement of the joints exceeds 0.4mm is mainly concentrated at the inverted arch. The joint shear displacement caused by the disturbance of shield tunnelling is greater than the joint normal displacement, so the potential failure mode of the surrounding rock in the sandy cobble stratum may be shear failure. The deformation of surrounding rock and liner in the discrete element model is greater than that in the finite difference model, so utilizing Discrete Element Method to verify the design of tunnel and liner is more secure and reasonable.
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Study on vibration monitoring and protection of ancient buildings under Metro Shield

Deng Wenbin, Sun Changkang, Yang Li, 乌郎·哈德力江

Abstract: (143) HTML (0) PDF (0.00 ByteKB) (0)

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In order to ensure the safety of subway shield tunneling through ancient buildings, the general technical route of first evaluation, first reinforcement, construction monitoring, later evaluation and later reinforcement is determined. By building a 1:3.52 physical model of ancient buildings and carrying out shaking table tests to obtain the damping ratio of the structure, using Ansys to build a three-dimensional model, using structural and modal analysis for vulnerable structures to strengthen and prevent, it provides a reference for the follow-up vibration monitoring and shield construction, and adjusts the construction parameters according to the construction monitoring data in the test area. The results show that the maximum displacement of the structure is about 14.01mm under static analysis, which verifies the validity of the three-dimensional model. The basic frequency of the structure model is 0.59046Hz, and the most vulnerable position is the sandalwood. In the process of shield tunneling, the acceleration of ancient buildings is less than 0.003m/s2, the vibration frequency is mainly concentrated in 0.6~20.5Hz, and the vibration frequency is in the normal range. The paper puts forward the overall solution of"The subway shield tunneling through the ancient buildings is mainly based on the uniform driving speed, avoiding the operation peak period, using the grouting reinforcement between the strata in the affected area, supporting the vulnerable structure of the ancient buildings, and adopting the vibration isolation and vibration reduction scheme during the construction", for the follow-up of similar projects to provide a reference.
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Domestic Research and Application Progress of Polyurethane Synthetic Sleepers

Xi Lei, Lv Rui, Zhang Jinlong, Huang Cheng, Zeng Fei, Zhang Yongbing

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Synthetic sleepers of fiber reinforced polyurethane foam were initially applied in urban railway traffic to adapt the linear induction motor system, and developed to the national and heavy-haul railway in recent years. Synthetic sleepers were widely researched and applied nationwide for their excellent overall performances. The technological development history and standards of synthetic sleeper in China were analyzed and compared with the foreign and ISO standards. Meanwhile, the application progress, application problems and solutions were investigated. Combined the requirements of the domestic rail traffic with the application problems of synthetic sleepers, the development suggestions and prospects of polyurethane synthetic sleeper in our country in the future are proposed.
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Analysis of Force and Deformation of Shield Tunnel under the Influence of Pre-dewatering in Adjacent Foundation Pit

LUO Cheng, XIA Xueqin, ZENG Yunrong, WANG Anhua, GUAN Lingxiao, XU Changjie

Abstract: (93) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

Foundation pit dewatering is an important factor causing soil deformation. However, there are few studies on the deformation of adjacent shield tunnels parallel to the foundation pit under dewatering conditions. In order to explore the stress and deformation characteristics of the existing tunnel caused by foundation pit dewatering, a three-dimensional numerical model is established based on the actual project. Taking the maximum vertical displacement of the tunnel as the evaluation index, the orthogonal table is used to screen the optimal combination and the main influencing factors, and then the main influencing factors are analyzed by univariate analysis to study the stress and deformation law of the tunnel. The research shows that through range analysis and variance analysis, it is found that the insertion depth s of the diaphragm wall is the main factor affecting the maximum vertical displacement of the tunnel outside the pit. Therefore, when the new foundation pit project adjacent to the existing tunnel has dewatering demand, this factor can be selected first to control the tunnel deformation. With the increase of the insertion depth of the diaphragm wall, the bending moment and deformation of the tunnel will decrease. After the insertion depth of the diaphragm wall reaches the soil layer with poor water permeability, the deformation of the tunnel will decrease significantly. At this time, the deformation of the tunnel can be effectively controlled, and it is of little significance to control the deformation of the tunnel by increasing the insertion depth. The dewatering causes the adjacent tunnel outside the pit to produce the "horizontal duck egg" settlement deformation towards the pit obliquely downward, and the deformation of the tunnel vault and the side arch waist of the adjacent foundation pit should be focused on during the construction process.
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Safety analysis of shield tunnel segment with cavity behind lining considering the influence of the joints

SHI Yufeng, HU Menghao, 顾大均

Abstract: (101) HTML (0) PDF (0.00 ByteKB) (0)

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In order to explore the influence mechanism of cavity on shield tunnel, a refined numerical model of shield tunnel considering ring and longitudinal joints was established. The variation law of internal force, deformation and section safety factor of the segment was investigated under various conditions such as depth, area and location of cavity, and the influence of different assembly points of the segment on tunnel with cavity behind was discussed. The results show that the order of the adverse effects of cavities at different positions behind the tunnel on structural safety is: tunnel waist > tunnel bottom > tunnel top. When the cavity area is 5.0 m2, with the increase of the cavity depth, the bending moment and safety factor of the tunnel section at the center of the tunnel top or the tunnel bottom cavity first decrease and then increase in the opposite direction, and the ellipticity of the segment first decreases to 0 and then increases in the opposite direction. The bending moment is reversed when the cavity depth is 0.3 m and 0.2 m respectively. The safety factor of the section at the center of the left tunnel waist cavity decreases continuously, and the ellipticity of the duct piece and the bending moment increase greatly. When the cavity depth is 0.5 m, the bending moment of the tunnel section at the center of the cavity at the top or bottom of the tunnel is reversed when the cavity area is 3.75 m2. The existence of circumferential joints within the cavity will reduce the internal force of the tunnel section at the center of the cavity and improve its safety factor. However, its maximum joint opening is 2.0~3.5 times that of the cavity without joint. The research results can provide reference for the safety evaluation of the cavity behind the lining of the shield tunnel and the selection of the assembly points.
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Simulation Study of a Longitudinal Induced Ventilation System in Tall and Large Factory Buildings of the Covered Metro Vehicle Base

Liu Qi

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The combination of metro vehicle base and upper property is becoming more and more, but the natural ventilation is not adopted and the traditional horizontal ventilation systems are difficult to set up? for tall and large factories in metro vehicle bases.And a longitudinal induced ventilation system which is applied to a metro tall and large factory buildings is proposed to solve the problems.Combined with a practical project, three-dimensional models of the longitudinal induced ventilation system at different installation intervals and heights in a factory building are established.And simulation is presented with different cases.The simulation results show that the longitudinal induced ventilation system can achieve good ventilation effects in tall and large factory buildings of? the covered metro vehicle base.This work will provide the basis for further project application of the longitudinal induced ventilation system.
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Research on the IFC-based BIM component standard library for rail transit engineering

BAI Minggang, ZHOU Gang, LAI Huahui, YANG Yuandong

Abstract: (138) HTML (0) PDF (0.00 ByteKB) (0)

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The rail transit engineering is in the stage of rapid development in China, and BIM (Building Information Modelling) technology has been widely applied in the lifecycle of rail transit engineering. However, the creation method and the information of BIM models from different participants are not unified, which makes it difficult to effectively and uniformly use BIM model data. Considering the diversity of BIM model creation software products for rail transit engineering, the IFC (Industry Foundation Classes)-based BIM component standard library for rail transit engineering was proposed. According to the expression requirements of rail transit engineering components, component types, IFC expression of component information and IFC-based extensibility mechanism were studied in this paper. The technology framework of this BIM component standard library for rail transit engineering contains basic layer, technical layer, application layer and user layer. To meet application requirements of BIM component models, the classification and code method in the national standard was used to define the classification and code of these BIM components; the encryption and decryption method for BIM component model was carried out to ensure the security of BIM model data; the component information template was proposed to define component properties and their resource links. The proposed unified BIM component library enables project participants to use the standardized BIM component models to create the project model of rail transit engineering, ensuring the standardization of BIM models.
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Research on the Capability Calculation Method of ATC Depot Throat Area

Huang Zongzhi, Xiao Yaling, Bai Yun

Abstract: (121) HTML (0) PDF (0.00 ByteKB) (0)

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Under the background that the departure capacity of depot has gradually become the bottleneck to improve the operation level of the main line in the morning peak, and some cities have begun to explore the construction of ATC depot, aiming the problem that the existing calculation method of vehicle sending and receiving capacity is difficult to apply to ATC depots, the throat area capacity calculation method of ATC depots is studied to make up for the above shortcomings. Under the ATC light-off mode, compared with the total train departure time in different train departure sequences to obtain the minimum total train departure time, and then the maximum throat area capacity of the ATC depot is calculated. Guangzhou Luogang depot is selected as a case study. The case results show that the method presented in this paper can effectively solve throat area capacity of the depot under the ATC light-off mode and provide data reference for the evaluation of the depot design plan. The comparative analysis results show that the ATC off-light mode can significantly improve the morning peak departure capacity of the depot and better meet the operation requirements of the morning peak line.
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Health Status Grading Evaluation Method of Subway Power Supply Equipment Considering Index Importance

Lin Sheng

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The condition-based maintenance mode can better solve the problems of " insufficient maintenance " and " excessive maintenance ", which is the development trend of existing research. The key premise of condition-based maintenance is to grasp the health status of equipment, so as to guide the development of condition-based maintenance work. In order to realize the effective health assessment of subway power supply equipment, this paper proposes a health status classification evaluation method of subway power supply equipment considering the importance of indicators. According to the combination of analytic hierarchy process and fuzzy statistics, the health value of the equipment is solved, and the importance of the index is taken into account. The health status of the equipment is graded. Taking the dry-type transformer as an example, the obtained results can reasonably characterize the health status of the subway power supply equipment, which proves that the method is reasonable and effective.
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Research of Cloud Play-control Technology in rail transit Passenger Information System

YANG Gang, SHU Jun, DONG Song, NIE Shoushuai

Abstract: (138) HTML (0) PDF (0.00 ByteKB) (0)

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The Rail Transit Passenger Information System (PIS) is a comprehensive and multi scenario information service system based on communication and multimedia technology, providing passengers with various display terminals; This article analyzes and studies the difficulties faced by the current rail transit passenger information system, such as excessive hardware investment, low deployment and debugging efficiency, long information playback links, multiple fault points, and poor reliability. It changes the traditional audio and video transmission methods and proposes a new generation of passenger information system cloud broadcast control architecture with "system in cloud, broadcast control in screen", where terminal display devices are directly connected to cloud management and control, Reduced 50% of transmission failure nodes under traditional solutions, ensuring stable and reliable operation of passenger information systems.
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Structure and Performance Evaluation of Prestressed Steel Strut Capable Against Tensile and Compressive

Zhang jinzhu, Zhang Jianliang, Li Yanchuan

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Considering that traditional steel strut cannot be tensioned, and construction of concrete strut is complex and generates a lot of construction waste during the demolition phase, the prestressed steel strut capable against tensile and compressive is invented. The performance evaluation results of mechanical, construction adaptability and the cost with prestressed steel strut capable against tensile and compressive show that, its compression bearing capacity is the same as that of traditional steel strut, equivalent to the concrete strut; its tensile and strut stiffness performances is equivalent to concrete strut, superior to traditional steel strut; its construction convenience is equivalent to traditional steel strut, superior to concrete strut; its cost is equivalent to traditional steel strut, 20%～30% lower than concrete strut. That the first concrete strut replaced by the prestressed steel strut capable against tensile and compressive for metro excavations not only ensures the technical performance, but also can achieve better economic and social benefits.
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The reconstruction practice and development thinking of using existing railway to operate suburban railway under “integration of the four networks”-A case study in Xi’an-Huyi Railway

JIANG Yanlin, 卢剑鸿, LI Xiao, 刘志鹏, 张文韬

Abstract: (104) HTML (0) PDF (0.00 ByteKB) (0)

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The advantage of using the existing railway to operate the suburban railway is that the investment is small and the construction speed is fast, but there is a lack of unified standards in planning, construction, operation and other aspects. Based on the functional orientation of suburban railway, and on the basis of sorting out the construction mode and operation characteristics of suburban railway develop on existing railway, this paper puts forward the key problems existing in the current policy system, the four-networks integration, operation effect and land development. Taking the reconstruction of Xi’an-Huyi railway as an example, analyze the mode of transportation organization, the characteristics of passenger flow, the mode of transportation connection, this paper discusses the applicability of the passenger-cargo mixed-run mode of single-track railway. In view of the future development of Xi’an-Huyi railway, this paper puts forward some strategies, such as improving the mechanism and system construction, optimizing the transportation connection scheme, improving the efficiency of operation organization, and accelerating the land development along the railway line, so as to provide reference for the subsequent reconstruction and improvement of existing railways.
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Simulation calculation of energy consumption based on multiple models of train operation

Liu Qinsheng, Chen Yalan, Wan Xin, Fu Minxue, Yi Dian

Abstract: (108) HTML (0) PDF (0.00 ByteKB) (0)

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Since train energy consumption has a large impact on the rail energy consumption, constructing a train energy consumption model is the basis for realizing energy saving and emission reduction of China's rail. Based on the single-mass point model and the multiple-mass point model of train operation, this paper constructs an energy consumption simulation model considering the motor dynamic efficiency. Taking the four stations and three intervals of a regional line in China as an example, the results show that the operation energy consumption under either the single-mass point or the multiple-mass point train operation model achieves a deviation of less than 5% compared with the actual energy consumption, which verifies the accuracy of the proposed energy consumption model. In addition, the operation energy consumption of the multi-mass model is further reduced by 1.66% deviation from the single-mass model. The proposed model provides a theoretical support for the optimization of train energy saving and actively contributes to the development strategy of China's green economy.
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Research of Urban Rail Operation Safety Evaluation Index System Based on Principal Component Analysis Method

HUI Changwu, XU Dejie, GONG Liang, ZENG Yuning, ZHONG Miaomiao

Abstract: (106) HTML (0) PDF (0.00 ByteKB) (0)

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Studying the distribution characteristics and cause mechanism of urban rail transit operation accidents is of great significance for ensuring operation safety and formulating safety control measures. This paper statistically analyzes 425 urban rail transit operation accidents at home and abroad from 1970 to 2022, and compares and analyzes the causes and time distribution characteristics of operation accidents. Based on the cause mechanism and the principal component analysis method, the safety evaluation system of urban rail transit operation is constructed, and the combined weight evaluation method based on game theory is proposed. Taking the data of 274 operation accidents in China from 1990 to 2022 as an example, combined with the expert scoring situation, the safety status of urban rail transit operation in China is analyzed from a macro perspective. The results show that the factors causing operational accidents include personnel factors, equipment factors and environmental factors. Among them, 47 % of foreign operational accidents are caused by personnel factors, and 65 % of domestic operational accidents are caused by equipment factors. January, March, July, August and December are the months with frequent accidents, which are the same as the peak months of passenger flow. The combination weighting method not only considers the amount of information in objective statistical data, but also combines the experience accumulation of subjective experts, which makes the evaluation results closer to the actual operation situation and more convincing.
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Nonlinear and synergistic effects of station-area built environment on metro ridership: A Shapley additive explanations (SHAP) analysis

YANG LINCHUAN

Abstract: (165) HTML (0) PDF (0.00 ByteKB) (0)

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The rapid growth in the number of motor vehicles has triggered a series of environmental and social problems. In this context, the metro, as a high-capacity and environmentally friendly public transportation mode, has become a crucial means of addressing the abovementioned issues. Although existing research has extensively validated the impact of station-area built environment on metro ridership, there has been relatively less focus on the nonlinear relationship and synergistic effects between the two. This study takes Chengdu as a case, utilizing multi-source big data, including metro card transactions and Points of Interest (POI), and employing interpretable machine learning methods (integrating random forests and SHAP models) to delve into the nonlinear relationship between the built environment and metro ridership, as well as the synergistic effects among built environment variables. The results of the study indicate that the three most important built-environment determinants of metro ridership are population density, road intersection density, and company density. The SHAP model results further reveal the threshold effects of the built environment around stations on metro ridership and the synergistic mechanisms among built environment variables. These findings provide theoretical support and policy insights for Transit-Oriented Development (TOD) goals in cities emphasizing public transportation.
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Field Test of Safety, Stability and Vibration Reduction of the Ladder-Slpeer Track in the urban rapid rail transit

Shen Qiongyu, HAN Dongdong, Dong Zhensheng, YU Quanyu, XU Feihu

Abstract: (124) HTML (0) PDF (0.00 ByteKB) (0)

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The study comprehensively summarizes the testing scheme and result of the ladder-sleeper ballastless track in the urban rapid rail transit of safety, stability and vibration reduction performance compared with the ordinary ballasted track under the maximum speed of 220km/h in 2023 on the National Railway Test Center Circular Line. The test used eight cars CRH380AJ comprehensive inspection units, the testing indicators included the safety and stability of the wheelset derailment coefficient, wheel load reduction rate, and wheel-rail lateral force, the vertical and lateral dynamic displacement indicators of the rail and the sleeper, the vertical and lateral vibration characteristics of rail, and vibration reduction performance of the roadbed surface at a distance of 3.5m from the centerline of the line. The test results of the abovementioned indices were lower than the limits of the relevant standard and basically, and close to the existing the ballasted track. The test results show that the safety, stability, and wheel-rail vibration characteristics of the ladder-sleeper ballastless track in the urban rapid rail transit can meet the requirements of the line at a speed of 220 km/h. According to different weighting methods, the average vibration reduction of the ladder-sleeper ballastless compared with the ordinary ballasted track in the urban rapid rail transit can reach 3.3～5.1dB and 4.4～6.8dB. The test results can provide references of the the urban rapid rail transit and the intercity railway track vibration reduction technology.
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Design and upgrade practice of urban rail big data platformbased on "Data Lakehouse" technology

Wu Yanjun, Guang Zhirui, Li Minghua, Chen Jianhua

Abstract: (168) HTML (0) PDF (0.00 ByteKB) (0)

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In order to explore the optimal scheme for the construction and upgrading of the big data platform in the urban rail transit industry, this paper takes the urban rail big data platform as the research object, starts from the development process of the urban rail big data platform, sorts out the three stages of the development of the urban rail big data platform, analyzes the technologies and advantages and disadvantages of the big data platform at each stage, focuses on summarizing the advantages of "Data lake and Warehouse integration, stream processing and batch processing integration, OLTP+OLAP, multiple loads" and other advantages of the "Data lakehouse" big data technology in the current stage, and studies the key points of the architecture upgrade and transformation design of the big data platform based on this technology. The technology is verified in the upgrading and transformation of the big data platform of the Beijing Metro data center. The application shows that the "Data lakehouse" big data platform technology combines the advantages of low cost of data lake and high performance of data warehouse, solves the shortcomings of the original big data platform in performance, capacity and multi-purpose support, and provides new solutions for the construction and upgrading of big data platform in the urban rail industry.
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Exploration of the Path of Reconstruction of Existing Lines of Urban Rail Transit

WEI Yun, CHU Baiqing, Guang Zhirui

Abstract: (241) HTML (0) PDF (0.00 ByteKB) (0)

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With the accelerated urbanization process, the reconstruction of existing lines of urban railways is of strategic importance in promoting the high-quality development of urban railways and sustainable urban development. The existing line transformation involves a wide range of professional and complex problems to be solved. It is difficult to meet the needs of the new period for the reconstruction of existing lines with eliminating hidden problems that aim to solve safety problems and the reconstruction which is just for some specialized field in the past. Therefore, it is urgent to explore in depth the development path of urban rail transit existing line transformation in the face of the requirements of high-quality urban rail transit development. Based on the history of the reconstruction of existing lines in Beijing, this paper analyses the demand for the reconstruction of existing lines of urban rail transit in terms of the problems faced and the realization of the future goals, proposing overall ideas for the reconstruction of existing lines. Also, we innovatively put forward the idea of investment and financing in the renovation of existing lines from the aspect of sustainable development of urban railways, and given suggestions for the transformation of existing lines in six aspects, i.e., system construction, vitality of elements, investment and financing mechanism, scientific and technological empowerment, technological research and development, and relevant standards, with a view to providing ideas for the transformation of existing lines of urban rail transit in China.
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The Vibration Reduction Effect of Vibration Reduction Measures of Chengdu Metropolitan Express Line

Xie Yumei, He Yulong, Xu Hong, Cheng Yujie, Zhou Wenxiang

Abstract: (97) HTML (0) PDF (0.00 ByteKB) (0)

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In order to evaluate the vibration reduction effect of the city express line, similar sections with basically the same line conditions were selected, and different vibration reduction measures and the corresponding common overall track bed sections were tested on-site to study the vibration reduction effect of the city express line vibration reduction measures. Through the time domain, frequency domain and 1/3 octave analysis of the measured data, the vibration reduction measures and the maximum Z vibration level (VLZmax) of the tunnel wall of the ordinary section are obtained, and the vibration reduction effects of different vibration reduction measures are compared. The vibration acceleration level of the tunnel wall at the measuring point and the ground vibration are analyzed in 1/3 octave to obtain the propagation attenuation of the vibration. The results show that the three vibration reduction measures have the vibration reduction effect, the vibration reduction effect of the double-layer nonlinear vibration reduction fastener is 7.3dB, the vibration reduction effect of the vibration damping pad floating plate is 16.2dB, and the steel spring floating plate has a vibration reduction effect of 16.2dB. And the vibration reduction effect of the steel spring floating slab is 19.7dB. The steel spring floating plate measuring point is seriously disturbed by ground traffic, among which the damping pad floating plate (ZK24+900) has a small attenuation, and the ordinary integral ballast bed (YK44+350) is attenuated due to its large burial depth and no environmental interference. maximum amount.
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Study on Intelligent Evacuation Technology of Metro Station Fire Based on Surveillance Video

tang pengcheng, sun ying, ding shizhneg, zhu yadi

Abstract: (119) HTML (0) PDF (0.00 ByteKB) (0)

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Fire is one of the most serious accidents in urban rail transit stations. A scientific and reasonable safety evacuation plan is an important guarantee to ensure the safety of passengers. However, the evacuation routes in the current subway station fire evacuation plan are difficult to dynamically adjust according to the fire situation. This study used computer vision technology to identify personnel distribution information and fire location based on the monitoring system in the subway station. Based on the information and available evacuation route information in the station, the evacuation route of passengers in the station was optimized to provide a more scientific and reasonable solution for evacuating passengers. The effectiveness of the evacuation plan had been verified through the application of three scenarios. This technology can be combined with the dynamic evacuation guidance system to improve evacuation efficiency and further ensure passenger travel safety.
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Discussion on the Construction of Intelligent Customer Service System for Urban Rail Transit

ZHAO Huawei, LI Jian, CHENG Yan

Abstract: (202) HTML (0) PDF (0.00 ByteKB) (0)

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In view of the problems existing in the existing customer service system, such as low perception level of passenger service demand, single service delivery channel, high cost and low efficiency of operation control, taking high-quality and efficient travel demand in the new era as the starting point, and analyzing the travel chain demand of different passenger groups, it proposes to take service timeliness, convenience, precision and initiative as the goal. The new architecture system of urban rail transit smart passenger service driven by multiple demands of online and offline dual-line services breaks through the bottlenecks of the existing system in data fusion, equipment platform integration, service quality, service efficiency and other aspects. While meeting the passenger service schedule, it focuses on the efficient execution of the last meter of service. Through the demonstration application of typical lines in Beijing subway, It provides a replicable and transferable technology system and application paradigm for comprehensively improving the intelligent service and management process of China's urban rail transit system.
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Passenger Flow Forecasting Technology for Initial Operation of Urban Rail Transit

LI Jinhai, DOU Liang, Zhang Meng, Qin Yizhan, SUN Yin

Abstract: (258) HTML (0) PDF (0.00 ByteKB) (0)

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The initial operation stage is a crucial stage for a new line with passenger services. Accurate forecasting of passenger flow for initial operation is a fundamental work for operational safety assessment and organization preparation. Considering the characteristics and difficulties of passenger flow forecasting in the stage, this paper proposes a set of forecasting techniques and introduces the key contents and main concerns of forecasting work. It is suggested that passenger flow forecasting should focus on the current situation of urban and urban traffic. It is essential to collect and understand the current information of urban traffic and city itself, mine spatial temporal big data, and analyze short-term development trends. On this basis, various traffic surveys are conducted to establish forecasting models to predict the expected passenger flow indicators of newly opened line and analyze its impacts on the existing network. In addition, a prediction sensitivity analysis should be carried out on key influencing factors. Since the accuracy of the passenger flow assignment model directly affects the accuracy of the prediction results, it is also necessary to build a special model for passenger flow analysis based on a macroscopic demand analysis by taking the entire network as the research object. Finally, the prediction results should meet the requirements of operational organization and safety management , and provide comprehensive prediction results, especially for special operational periods, special stations, and non-routine operational scenarios.
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Research on Key Technologies of 160km/h Urban Rail Express Gauge

LIU Xin-Ming, WANG Jian, WANG Jia-qing

Abstract: (132) HTML (0) PDF (0.00 ByteKB) (0)

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The main technical parameters of urban rail express gauge for A-type vehicle with a speed of 160km/h have exceeded the scopes of current national norm and standard. However, there are few studies on it until now. Based on the researches on gauge system and calculation method at home and abroad, our study adopts theoretical analysis and dynamic simulation methods together. The calculation formulas in Standard of Metro Gauges (CJJ 96-2003) are adjusted, so as to be suitable for the 160km/h express project. The optimal structure gauges of station, tunnel and bridge are formulated in combination with express project characteristics under the researches on basic parameters of gauges.：(1) Compared to the stopping condition, when the train passes the station at 100km/h, the distance between station platform and central line of track is 1,600mm； (2) The size of circular tunnel section is determined by space requirement for equipment layout in urban rail express project. When the flexible overhead contact system is adopted, the optimal net size in tunnel is 7.5 m. While the rigid overhead contact system is adopted, the optimal net size in tunnel is 7.1 m.
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Application Practice of Carbon GSP for Shenzhen Rail Transit

Zhou Shi Shuang, Yang Xiang Ming, Zhang Xue Mei, Wu Chao Ran

Abstract: (233) HTML (0) PDF (0.00 ByteKB) (0)

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Public participation in low-carbon travel is an effective way to reduce carbon emissions. How to further guide and incentivize public participation in low-carbon rail transit through carbon inclusive mechanisms is an important research field for rail transit enterprises to carry out green and low-carbon practices,this paper according to the national carbon peak, carbon neutral and carbon GSP policies, as well as the construction of carbon GSP policy system in Shenzhen; This paper focuses on the "Our Low-Carbon Road" project, combines the mechanism of carbon GSP in Shenzhen and the characteristics of the urban rail transit industry, relying on the Internet technology and data aggregation platform to systematic analysis was conducted on the business model, methodology, business process, and data flow, the system architecture and technology program of Shenzhen's carbon GSP application platform, as well as the implementation and application significance of the platform, and puts forward the development ideas of expanding carbon application scenarios, innovating carbon financial products, and cross-regional cooperation. It has provided Shenzhen experience for the application of urban rail transit in the field of carbon inclusion, which is of great significance for exploring the potential of public emission reduction, stimulating green travel for citizens, and nurturing the rail transit industry.
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Experiment and Simulation Research on Vibration of Rubber-tyred Suspended Train and Steel Bridge

LI Qi, LV Chao

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Field experiments and simulation analysis were conducted on the Kaifeng suspended mono-rail demonstration line in this study to evaluate the service performance of the rubber-tyred suspended vehicle and the steel guideway bridge, and to provide appropriate criterion and operating and designing parameters for this type of vehicle-bridge systems. A rubber-tyred Suspended Train-Steel and Guideway Bridge Coupling analysis program was developed. The vehicle-bridge coupling model was built according to the measured parameters including the stiffness and damping of the pneumatic spring and the travel wheels. The calculated and measured results of dynamic response of the vehicle and the bridge were compared. Finally, the dynamic performance of the vehicle and the bridge structure was evaluated based on the calculation and related specifications. The results show that: 1) it is feasible to apply the vehicle-bridge coupling simulation method to the investigate the structural vibration performance of suspended mono-rail system, because of the results of simulation being in consistent with those from the field measurement; 2) the ratio of the vertical deflection to the span of the steel guideway girder is less than the limit given by the relevant specifications and the vertical stiffness of the structure is reasonable; 3) the maximum vertical and lateral rotation angles between two adjacent beams at beam-ends are 4.5‰ and 1.5‰ respectively; 4) the maximum dynamic factors of longitudinal and lateral stress of the steel guideway beam are 1.17 and 1.14 respectively under vehicle speed 80 km/h; 5) the unloading factor of the wheel and lateral acceleration of the guideway bridge is relatively larger than those of conventional railway systems, so that the limitations of these two indices could be set larger than the current railway specifications since the suspended trains are unlikely to derail.
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Definition and Characteristics of Tourism Rail Transit

lisiwei, lufang

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Tourism rail transit (TRT) is a developing mode of transportation in China, with some cases of implementation. TRT encompasses both tourism and rail transit aspects. This paper examines the definition of TRT and underscores its advantages over road traffic. As a distinct application of rail transit, TRT has characteristics that differ from general urban rail transit. Thus, the direct adaptability of urban rail transit experience to TRT is not recommended. From the perspectives of planning, design, operation, and economy, this paper summarizes the main features of TRT, including relatively small scale, low sensitivity to speed, favorable economic benefits, and high landscape requirements. Based on these characteristics, a suitable system of mid- to low-volume rail transit is proposed, along with some development suggestions.
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Research on whole life cycle carbon emissions based on actual metro lines

lixiaofeng, 王荔, 栾承志, 于秋燕

Abstract: (230) HTML (0) PDF (0.00 ByteKB) (0)

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Under the major strategic deployment of dual-carbon strategy, to study the whole life cycle carbon emission of rail transit and to reasonably quantify its carbon emission level is an important issue to achieve peak carbon and carbon neutrality in the transportation sector. Based on a new metro line in Beijing, this paper analyzes the whole life cycle carbon emission of rail transit, establishes a carbon emission calculation model for the whole line and the whole life cycle of rail transit, and quantitatively calculates the carbon emission of the whole line and the whole life cycle of the new metro line. At the same time, the carbon reduction measures in the construction phase and operation phase are analyzed and their carbon reduction potential is quantitatively assessed. The carbon emission calculation for the 81km long new metro line yields a carbon emission of 2.57 million tons of CO2eq in the construction phase, 54,000 tons of CO2eq per year in the operation phase, and a total carbon emission of 5.24 million tons of CO2eq in the 50-year operation cycle. The use of renewable materials and prefabricated structures in the construction phase can reduce carbon emissions by 7%; the use of comprehensive carbon-reducing measures in the operation phase can reduce carbon by 27%; and the carbon reduction potential of the 50-year operation cycle totals 17%. The model bridges the gap in the field of carbon emission calculation for the whole line and whole life cycle of rail transit, and is of guidance to the quantitative calculation of carbon emission for the whole life cycle of urban rail transit. The research results of carbon reduction measures can provide references for urban rail transit to achieve green and low-carbon transformation, and to achieve carbon peaking and carbon neutrality in the transportation sector.
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Research on the Technical Standards for the Renovation of Existing Lines in Urban Rail Transit

WEI Yun, CHEN Yan, ZHAO Huawei, YANG Jun, CHENG Yan

Abstract: (159) HTML (0) PDF (0.00 ByteKB) (0)

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The renovation of existing lines is an important long-term task for China's urban rail transit to achieve high-quality and sustainable development in the future. Technical standards serve as important basis for the initiation, design, and implementation of urban rail transit line renovation projects. This article reviews the current status of the technical standard system for urban rail transit and analyzes the adaptability of existing standards to each link of the renovation projects work process. In response to the problems of incomplete coverage, insufficient applicability, and weak pertinence of existing standards for renovation project, two approaches and schemes for the construction of the technical standard system for the renovation of urban rail transit existing lines are proposed, along with principles for the construction and formulation of standards. The focus of the discussion is on the formulation of technical standards for urban rail transit existing lines renovation, including requirements for renovation determination, renovation design, renovation construction, acceptance and pre-operation safety assessment, and post-evaluation requirements.
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Review and Prospect of Shanghai Urban Rail Transit Existing Line Reconstruction

WANG Zhenbo, LU Jing, SHI Dongyan

Abstract: (94) HTML (0) PDF (0.00 ByteKB) (0)

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Shanghai has been a forerunner in the field of urban rail transit operating line renovation in China due to the early opening of urban rail transit. The experience and lesson of Shanghai in operating line renovation have some reference value for other cities in China. Therefore, the operating line renovation process of Shanghai urban rail transit was reviewed firstly. Then its three main development trends have been concluded that the focus is in a gradual transition from individual situation to overall situation, the renovation contents are gradually diversified and systematized, the renovation demands which align with the development goals of city and urban rail transit network are continuously deepening and expanding. Secondly, drawing up renovation plan with systematic thinking before the renovation, minimizing impact on passengers while ensuring construction safety and quality during the renovation, and carrying out post-evaluation actively after the renovation were summarized as the key points in carrying out the operating line renovation of Shanghai urban rail transit. The difficulties in carrying out the operating line renovation of Shanghai urban rail transit were analyzed from the aspects of limited financial support, high efficiency requirement for internal and external communication, challenge of project management, and insufficient technology accumulation. Finally, the important future works for the operating line renovation of Shanghai urban rail transit were prospected, including exploring more financing channels, carrying out research on the improvement and innovation of construction plan and management mechanism, deepening the evaluation of the operating urban rail transit network, and tackling the technology of non-closure renovation of underground station without pre-reserved condition.
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Study on the impact of shallow buried rectangular jacking pipe construction on adjacent pipelines and ground surface

HAN Zhonghui, Wang Mei

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Abstract:

The ground surface deformation characteristics caused by rectangular pipe jacking construction differ from those of circular pipe jacking or shield tunnels. In order to clarify the ground settlement characteristics during the construction of the shallow buried rectangular pipe jacking and the impact on the existing shield tunnel below the pipe jacking. Based on the monitoring results of the rectangular pipe jacking construction on site, the deformation pattern of the ground surface during the construction of the rectangular pipe jacking and the deformation of the existing shield tunnel below the pipe jacking were analyzed. The traditional Peck"s formula is applied to circular pipe jacking or circular shield tunnels, so the improved Peck"s formula is used to describe the surface deformation caused by rectangular pipe jacking; the surface deformation, pipeline deformation and settlement pattern of the submerged tunnel caused by the pipe jacking construction are analyzed based on the field monitoring. The study shows that the improved Peck formula can accurately describe the surface deformation caused by rectangular pipe jacking construction compared to the traditional Peck formula; the settlement pattern of the surface and the pipeline above caused by pipe jacking construction is consistent, but there are differences with the settlement pattern of the underlying tunnel.
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Track inspection vehicle routing problem under the urban rail transit network

huzhenghan

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The quality of the metro track is crucial for residents to travel. A track in good condition is the basis for smooth and safe operation. The urban rail transit companies regularly operate track inspection vehicles to check the track condition. Due to the lack of systematic modeling methods, the current operation path of the track inspection vehicle largely relies on expert experience. This article takes proposes the Urban Track Inspection Vehicle Routing Problem (UTIVRP) and applies it into the urban rail transit network. A Memetic Algorithm (MA) with a special encoding method was designed based on the characteristics of the local railway network, and analyzed through an actual example of the Beijing subway. The experiments results show that, the optimization scheme can not only reduce the idle distance by 48.882%, but also reduce the maximum deviation rate of the detection interval of the road network by 90.115% under the condition of meeting the practical requirements.
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Research on the influence and quality control of horizontal MJS pile in water-rich silty sand stratum

王占生, WANGQING, 张宗超, LiWenTao

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Metro Jet System (MJS) construction method has the advantages of omni-directional, high-precision, centralized mud discharge, etc., and shows high adaptability under the unfavorable construction conditions such as complex and changeable geology, and traversing existing stations using shield tunneling. In order to study the effects of horizontal MJS pile constructed within silty sand stratum and to optimize the design and construction parameters of horizontal MJS, MJS pile test was conducted in a subway station of Suzhou Rail Transit Line 6. The field test was performed to study the developing trend of groundwater level, excess pore water pressure, soil pressure and deep horizontal displacement caused by horizontal MJS pile construction. The results show thatthe maximum excess pore water pressure increases by 46.1 kPa during horizontal MJS shotcreting during pile testing. The water level will rise by 3.6 m at most during shotcreting, and will drop by 1.5 m at most after shotcreting. The variation trend of earth pressure is consistent with that of pore pressure, and the maximum increment of earth pressure during shotcreting is 40.6 kPa. Due to the insufficient self-supporting capacity of the soil mass during the hole drilling in the silty sand layer, the hole is easy to collapse. During this process, the inclinometer during the hole drilling has a maximum inclination of 1.2 mm, and the inclinometer during shotcreting has a maximum inclination of 2.2 mm. The maximum displacement of the station floor during the horizontal MJS construction in a subway station in Suzhou is 0.8mm, which meets the specification requirements. During the construction of MJS piles within silty sand layer, 3% bentonite can be added to the cement slurry to avoid hole collapse and drilling holding problems.
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Construction technology of cutting large diameter main reinforcement pile group with EPBS at oblique angle

Yang Zhiyong

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Taking the section project between Guanzhou Station ~ University Town North Station of Guangzhou Metro Line 12 as an example, the practical research of shield direct cutting pile diameter of 1200mm and main reinforcement diameter of 25mm and 28mm pile group was carried out, and the key measures and pile cutting effect of shield construction were analyzed. Practice shows that the tool configuration with hob and tear knife has the ability to cut the concrete pile foundation with the diameter of the main reinforcement of 25mm and 28mm; It is difficult for the toothed hob to cut the steel bar directly, and the shear force on the steel bar during the secondary action of the tearing knife can cut off the cutting position of the hob; The use of "low pushing speed, high rotational speed, and stable torque" method of boring can effectively cut the pile body and steel bar; The use of split hydraulic rebar shears can better handle the winding steel bars in the shield.
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Quality deviation evaluation of shield segment assembly based on 3D point-cloud

Wuningqi, Wang weijun, Chenlijuan, Wuqinglin, Xiexiong

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In the process of tunneling, due to the poor control of the shield machine posture or other factors, shield segment assembly often happen quality errors such as dislocation and ellipse deformation. This quality errors threaten the stability and safety of the tunnel, in order to ensure the safe construction of shield tunnel, it is critical to timely feedback the quality of shield segment assembly. In view of the difficulties, low efficiency, limited accuracy and incompleteness data in conventional quality of shield segment assembly, 3D laser scanning was introduced to conduct point cloud data that present the assembling of shield segment lining, the ellipticity and misalignment value of shield segments is respectively calculated; and based on the theory of center point extraction of ring seam data, a method of extracting the central axis and center point of tunnel by ring segment data fitting is proposed to realize high precision, high efficiency and automatic detection of shield segment assembly quality .Finally, a shield tunnel project is conducted to demonstrate and validate the proposed method. The results show that the proposed method can efficiently and automatically estimate the assembling quality of shield construction segment.
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Experimental Study on the Vibration Reduction Effect and Displacement of Multi-level Vibration Reduction Prefabricated Track Bed

YIN Xuejun, LAN Huifeng, LI Huichao, LIU Yongqiang, LI Guoyu, QIN Mingjun, 洪彧

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In order to study the vibration reduction effect of different levels of composite vibration reduction prefabricated track beds, the vibration and displacement response of high and medium level composite vibration reduction pad prefabricated track beds and ordinary track beds were tested at a speed of 70 km/h in the Zhang-Peng section of Qingdao New Metro Line 4. A comprehensive evaluation was conducted by introducing the root mean square value of the frequency division vibration level of the lead hammer Z vibration level and the transmission loss of the Z vibration level, The vibration characteristics of prefabricated track bed tracks and ordinary track bed tracks with two different damping levels of composite damping pads were compared and analyzed in the time and frequency domains. The results showed that: (1) the tunnel wall frequency division vibration levels of the three different damping types of track bed tracks reached their maximum at 50-80Hz. Compared with ordinary track beds, the damping effects of high and medium damping track beds (average root mean square difference of frequency division vibration levels) were 13.9dB and 8.5dB, respectively; The Z-level transmission loss values between the track bed and the tunnel wall are 45.8 dB and 35.1 dB, respectively; (2) During actual operation, the vertical displacement of the high, medium damping track bed, and ordinary track bed are 1.683mm, 0.421mm, and 0.145mm respectively, and the lateral displacement of the track bed is 0.346mm, 0.087mm, and 0.051mm, respectively. The multi-level vibration reduction universal prefabricated track bed has obvious vibration reduction effects for vibrations above 20Hz, and can freely choose and change the vibration reduction level according to different needs, which has certain guiding significance for the development of vibration reduction universal prefabricated track bed.
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Research on Methods of Running Express/Local Trains on Existing Lines of Urban Rail Transit

wenqian

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Few approaches are available to effectively improve the operation of existing lines of urban rail transit. As a bold attempt and innovative breakthrough, running express/local trains on existing lines can be applied to a wide range of scenarios under high-quality development. After systematically reviewing the methods of running express/local trains on existing lines, this paper proposes four methods of running express/local trains on existing lines according to the characteristics and operational requirements of different lines, namely, using large intervals to run fast trains, using alternate skip-station stopping to run fast trains, using failure train stop lines to run express/local trains, and using part route shuttle to run express/local trains. In combination with the application cases at home and abroad, the paper probes into the operating principles, advantages and disadvantages and operational requirements of the aforementioned methods, followed by an introduction of the renovations to be made for running express/local trains on existing lines.
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Study on Risk Analysis Technology of Fully Automatic Operation System

XUE Weiqing, HU Feiyan, LI Yan, GAO Bohan, ZHU Sheng, DING Yi

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In order to ensure the safe operation of Fully Automatic Operation (FAO) system in urban rail transit, a technical method for safety risk analysis at the overall system level of FAO system is proposed, which is capable to comprehensively identify risks of FAO system design. This method mainly identifies safety related weaknesses in the design of the FAO system through standard difference analysis, hazard scenario composition analysis, and scenario hazard analysis. Finally, it puts forward corresponding functional safety requirements, technical safety requirements, and operational safety requirements for each core subsystem, equipment, interface, operation and maintenance, and construction of the FAO system. It provides a certain reference value for the subsequent engineering projects to carry out the risk analysis at the overall FAO system level.
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Study on the Risk Prevention and Control System of Existing Structure Leakage in Beijing Subway

Yang Guangwu, Peng Hua, Li Yujie, Li Zichen, Wan Kuangdi, Song Wei

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Aiming at the serious leakage problem of subway structure caused by the rise of groundwater level in Beijing, how to scientifically and reasonably manage and prevent and control the leakage of Beijing subway has become the key of current research. In this paper, from the existing subway structural leakage risk identification, risk evaluation and risk response strategy, the existing structural leakage risk prevention and control technology system of Beijing subway has been systematically researched and analyzed. Firstly, starting from risk identification, the factors causing leakage damage are analyzed in all aspects. Further, based on the risk identification, the research work of risk evaluation and grading was carried out, and the subway leakage diseases were categorized and graded according to the qualitative and quantitative methods for the intervals and station structures, and the leakage grades of A, B, C, and D were given to make the emergency response and conventional leakage control measures. Finally, corresponding leakage risk response strategies are proposed, including emergency response and general leakage treatment. The research content can provide theoretical reference and technical support for similar subway structural disease management system.
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Research on Wear Measurement of Rigid Catenary Based on a Filter Tracking Algorithm

yuqiubo, hanchaojian, lujun, niguozheng

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Currently, the overhead rigid catenary system power supply method is commonly used to provide electrical power for the subway in urban rail transit. The wear state of the rigid catenary system is an important indicator related to the matching relationship between the pantograph and the rigid catenary system. If the wear exceeds the limit, it will lead to serious faults of the pantograph and the rigid catenary system. This study focuses on the rigid catenary system of the subway, and this method uses a line laser and a high-speed area array camera to capture the contour of the light strip in real-time. Based on the improved channel reliability, a multi-scale background perception correlation filtering tracking algorithm is used to fit and calculate the wear value, effectively handling complex factors such as lighting, scale, and occlusion, achieving high tracking accuracy and success rate, with an accuracy of up to 94%. This method replaces manual measurement with dynamic continuous wear measurement to achieve continuous, comprehensive, and efficient detection of the rigid catenary wear status. It can greatly improve the efficiency and accuracy of the wear measurement, achieve comprehensive control of the rigid catenary system, and provide guidance for preventive maintenance of the catenary. The continuous measurement of contact wire wear is achieved, and the measurement efficiency is significantly improved. On the basis of the original monitoring of catenary wear data, tracking monitoring of the growth rate of catenary wear has been added. When the growth rate of catenary wear is too fast, manual inspection frequency will be increased to ensure the safe operation of catenary equipment.
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Research on the Differential Countermeasures on the Long-Collinear Excavation Induced Underlying Deformation and Corresponding Effectiveness

ZHANG Chengcheng

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Overlying excavation easily causes stress relief of the soil above the underlying tunnel, which easily induces tunnel heave and affects the serviceability of the tunnel. Based on the reconstruction project of the Guimiao Road in Shenzhen, this paper proposes differential countermeasures for the underlying tunnel heave subjected to the overlying excavation in different sections and verifies the effectiveness of the measures through field measurements. The results show that the closer to the excavation center, the larger the heave of the underlying tunnel and the unloading rate of the soil. Excavation-induced soil stress relief does not affect the tunnel deformation when the excavation area is more than 30 m away from the tunnel. For different excavation areas, (1) Longitudinal Segmentation + Vertical stratification + Separate excavation for left and right side; (2) Longitudinal Segmentation + Vertical stratification + Separate excavation for left and right side + Reinforcement of high-pressure jetting piles; and (3) Spaced shaft excavation + anti-heave frame were adopted, the measured data show that the effectiveness of these measures is generally satisfactory. It can provide important references for similar projects.
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Discussion on the Design of Longitudinal Gradient of Additional Stations and Wiring in Metro Existing Line Sections

LI Ming

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This paper preliminarily explores the selection range of longitudinal slope for adding stations in the existing line renovation project, and analyzes the requirements for longitudinal slope from several perspectives, such as train stopping smoothness, train starting and braking, station longitudinal drainage, station building and accessibility design, station platform door installation, and station wiring, And some conclusions are put forward: (1) It is necessary and sufficient to verify the technical performance of parking braking, starting and braking of subway trains, which is the key to determining whether the longitudinal slope of adding stations in existing line sections can be moderately enlarged; (2) Taking into account the parking and braking performance of subway trains, as well as the technical performance of train starting and braking, the longitudinal slope of the station should be allowed to be moderately enlarged. However, considering the design of the station building and the convenience of passenger use, this amplitude should not be too large; (3) From the perspective of maintenance and repair of switches, it is recommended that the longitudinal slope of switches should not exceed the existing regulations of 10 ‰.
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基于云平台的城市轨道交通自动化集成系统架构与实践 Architecture and Practice of Urban Rail Transit Automation Integrated System Based on Cloud Platform

WU Zheng-zhong, DENG Neng-wen, Wang Xiao-dong, Wang Yong-gang, Wu Tao, Liu Xin

Abstract: (183) HTML (0) PDF (0.00 ByteKB) (0)

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Under the traditional architecture, each subsystem of urban rail transportation weak electricity system is independently installed, with various equipment, complex maintenance, low degree of interconnection and other defects, which is difficult to meet the construction needs of "intelligent urban rail" to break the data barriers of various information systems. In view of these defects, this paper proposes a solution based on "digital cloud base" to build software modularization and intelligent hardware integration design ideas, applying cloud computing, big data, edge computing, artificial intelligence and other general information technology, combined with super-convergence intelligent hardware development technology, big data center technology, distributed cloud platform technology and microservices. Comprehensive governance platform technology solutions, and developed a cloud-based platform of urban rail transit automation integration system (hereinafter referred to as the cloud traffic system). By analyzing the characteristics of rail transit business, we designed the architecture and micro-service reconfiguration mechanism of the cloud transportation system, integrated big data and middle platform technology, and applied it in several projects through the highly integrated intelligent control all-in-one machine. The application effect shows that the cloud transportation system helps to improve information efficiency, reduce operation and maintenance costs, and support scientific decision-making.
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Discrete element simulation of rock breaking characteristics of one-way non-through jointed rock mass by hob

chenxiaojian

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Compared with the penetrating joint, the existence of rock bridge makes the failure process of non-penetrating jointed rock mass more complicated. In order to explore its influence on rock breaking, the discrete element model of rock breaking by disc cutter in unidirectional non-penetrating jointed rock mass is established by using PFC2D. The influence of rock bridge length and dip angle on rock breaking mode, normal force, crack number and specific energy consumption is studied, and the rock breaking characteristics of disc cutter in non-penetrating jointed rock mass are revealed. The results show that the rock mass is dominated by tensile failure, and the joint has obvious "guiding effect" on crack growth, and the crack growth direction always tends to the nearest joint. The vertical stress level increases first and then decreases with the increase of joint dip Angle, and reaches the maximum value at 45° dip Angle. The shape of the stress zone is affected by the joint position, and the two are consistent. The mean value and peak value of normal force of intact rock mass are greater than jointed rock mass, and jointed rock has obvious promoting effect on rock breaking process. The specific energy consumption at 0°, 60° and 90° joint dip Angle is significantly lower than that of other joint combinations. The energy consumption decreases at 60° joint dip Angle, and the minimum value is obtained when the length of rock bridge is 25mm, at 0° and 90°, it decreases first and then increases, and the minimum value is obtained when the length of the rock bridge is 15mm.
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Research on Maintenance Strategy of Urban Rail Vehicles: A Case Study of Beijing Rail Transit

Zhixiang Song

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Focusing on the challenges of maintenance cost control and limited vehicle maintenance resources of large-scale urban rail transit network, vehicle maintenance interval, resource sharing and commercial mode were discussed in the context of the intelligent maintenance, maintenance resource sharing, and the packaging of vehicles bidding and maintenance services in hte case study of Beijing rail transit..After research and analysis, three strategies were put forward, which are the whole life-cycle repair strategy based on the intelligent operation and maintenance, the centralized maintenance of components based on resource sharing, and the packaging of vehicles bidding and maintenance services.
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Control Strategy of Flywheel Energy Storage System in Urban Rail Transit

Zhao Xiaohao, ZHANG Gang, SONG Jiatong

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In order to address the issues of network voltage fluctuations and energy waste caused by frequent traction and braking of urban trains, this paper proposes a charging and discharging control strategy based on the DC side voltage of the traction network for the flywheel energy storage system applied in urban rail transit. The average speed control method is used to adjust the speed difference of the flywheel array due to different processes and environments. On the basis of the existing control strategy, an empty load network voltage identification algorithm is proposed to avoid flywheel misoperation caused by voltage fluctuations in the medium voltage ring network. On this basis, this article models and simulates the traction power supply system with flywheel energy storage system, and connects the flywheel energy storage device to the traction substation for on-site experiments. The flywheel energy storage system effectively suppresses the fluctuation of traction network voltage, reduces the peak output power of the traction power supply station, verifies the feasibility of the control strategy and the energy-saving effect of the flywheel energy storage system, providing reference and reference for the further application of the flywheel energy storage system in the field of urban rail transit.
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Characteristics of Express/local train Operation Organization of Tsukuba Express and Related Inspirations

wen qian

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Tsukuba Express (TX) is a suburban commuter line that connects Akihabara Station (Chiyoda-ku) with Tsukuba Station (Ibaraki Prefecture). It was operated the latest in the Tokyo Metropolitan Area but the line that applied the largest number of new technologies. TX was planned, designed and managed based on a lot of precious experience of practitioners of Tokyo rail traffic, thus being a learning example for the domestic rail traffic industry. Depending on the express/local train mode and the refined operation organization, TX realized simultaneous operation of different types of fast and slow lanes in a line and satisfied the differential travel demands of the suburban passengers. It made profits in the year after the 5-year operation, advanced social and economic development along the line and achieved distinctive economic and social benefits. The paper deeply analyzed the operation strategy, planning and design, and management mode of the available express/local train from the view of the operation organization, and expected to provide experience in planning, design and operation management for domestic express/local train in operation to a certain extent.
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The Study of Sustainable Development Comprehensive Evaluation of China URL Based on OCGS

YU Songwei, LIU Wei, ZHONG Yingying

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China URT is gradually moving towards the "operation and construction era" dominated by operations, in order to further promote high-quality sustainable development, this article conducts a comprehensive evaluation study on the sustainable development of URT in China. Starting from the system elements of "one center-three axes-four layers", the elements relationship between input-configuration-operation-output-feedback, and the characteristics of OCGS, it is discussed that URT is an "open technicalsocio complex giant system"; secondly, based on the three-dimensional concept interlocking model of economic, social, and environmental, a comprehensive evaluation system for URT sustainable development was established, consisting of an evaluation element system and an evaluation business system; next, the methodology of " A human-computer interaction method of fusion of linear-nonlinear" was established, and the difficulties of current knowledge data dual drive artificial intelligence evaluation methods were overcome, then "a dual wheel drive of deep fusion knowledge data algorithm based on prior information" was proposed, laying the foundation for the next step of application.
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A review of node-place model for integration of urban rail and land use

xuqi

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Station area is the main area where urban rail and land use interact with. The integrated development of transportation and land use in urban station area is a key problem in traffic planning and urban studies. TOD (Transit-oriented development) is not only a community development mode guided by public transport, but also a high-quality development concept of the integration of transportation and metropolis. The node-place model proposed by Bertolini can effectively measure the coordination between transportation and land use in the area of public transport stations, and correspondingly providing an analytical framework for the integrated development of TOD. This paper first introduces the basic concept of TOD and the integrated models of urban rail and land use from the perspective of built environment. And then we state the classical form of node-place models and its improved models, summary the built environment indicators and pedestrian catchment area parameters of node-place models. Finally, we conclude the classical application scenarios of node-place models, and puts forward its limitations and development direction. Systematically reviewing the node-place models for integration of urban rail and land use can help to better evaluate the integration of transportation and land use and promote the coordinated development of urban rail stations.
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Discussion on Train-to-Train Communication Technology for Train Control System in Urban Rail Trainsit

Zhu Li, Gong Tai Yuan

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This paper conducts a comprehensive study from basic technology to application simulation for the train-to-train (T2T) communication technology, which is an important development direction in train operation control systems. Firstly, the basic principle of train operation control system based on T2T communication and its key technologies are introduced; secondly, the current mainstream T2T communication technologies based on logical point-to-point and physical point-to-point are investigated; finally, the modeling and simulation calculation and analysis of T2T communication distance are carried out with the typical operation scenario of T2T communication in urban rail transit; the simulation results show that the T2T direct communication distance in the non-tunnel area is about 765.8 meters at 1.8GHz and 923.6m at 1.4GHz in the non-tunnel area, while the direct communication distance is about 511.3m at 1.8GHz and 724.8m at 1.4GHz in the tunnel area; if the T2T distance exceeds this range, the logical point-to-point communication method should be used. This study aims to provide useful reference and theoretical basis for the design and application of T2T communication system in next-generation urban rail transit.
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Predicament and Expectation of Low Volume Urban Rail Transit Construction

XIANG Hong, LIAO Xiangchenchen

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After nearly 30 years of rapid development of urban rail transit in China, 55 cities in mainland China (excluding Hong Kong, Macao and Taiwan) have built about 10288 kilometers of urban rail transit, effectively solving the problem of public transport congestion in most large and medium-sized cities. At the same time, the high operating cost of rail transit and the pressure on the urban economy are becoming increasingly prominent. Recently, the relevant policies issued by the state show that during the 14th Five-Year Plan period, the first round of urban rail transit construction planning applications for unqualified cities and general prefecture-level cities will no longer be accepted, and the construction of urban rail transit is tightening. Therefore, how to make the cities in need reasonably choose the construction of low-volume rail system, consolidate and strengthen the problem of low-volume rail connection at the end of urban rail network, and let the small and medium-sized cities with economic capacity adjust measures to local conditions, reasonably select types, and use low-volume rail transit to solve urban public transport problems has become a hot topic in the industry. From the perspective of planning and design of rail transit for a long time, the author analyzes the classification of low-volume rail transit and the content of programmatic documents such as construction guidelines.Combining with his own experience in planning and design of low-volume rail transit projects, the author combs the difficulties faced by the development status of low-volume railway system, and puts forward five suggestions to deal with the difficulties of construction of low volume rail transit. The purpose is to promote the healthy development of urban rail transit.
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On the Spatial Noise Distribution of Double-deck Rail-cum-road Viaduct with Different Road Bridge Types

Li Qi, Wang Mengyi

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The independent rail transit viaduct has advantages of low construction and operation costs, but it produces significant environmental noise pollution to the nearby residents. However, the upper road bridge of the double-deck rail-cum-road viaduct can act as a barrier to reduce the upper zone noise originating from the rail transit traffic. In order to analyze the spatial noise distribution of double-deck rail-cum-road viaduct with different road bridge types, a two-dimensional acoustic model is established to predict the track noise propagation characteristics based on the measured rail vibration acceleration. Firstly, the accuracy of the proposed method is verified by the field noise measurement results. Secondly, the noise propagation and distribution characteristics are compared among those from the independent rail transit double U-beam viaduct, the double-deck rail-cum-road viaduct constructed with the small box-girders as well as the hollow slab beams. Finally, the noise mitigation mechanism of the double-deck viaduct is explained. The results show that the upper road bridge changes the transmission path of noise, which can reduce the noise in some areas (above the road bridge side) while increasing the noise under the bridge. Meanwhile, the noise under the road bridge significantly is increased due to the reflection of sound by the road bridge. Additionally, in the area above the road, the small box girders significantly reduce the noise level compared with the hollow slab girders, with a decrease generally between 6~11dB(A), and the maximum decrease is about 21dB(A). The small box beam with uneven bottom can better limit the acoustic energy within the zone below the road bridge, and achieve a greater noise reduction effect in the area above the road. The proposed noise prediction method can provide a reference for the noise prediction from the rail track of the double-deck rail-cum-road viaduct, and the calculation results can provide an acoustic performance basis for the selection of the road bridge type for the double-deck viaduct.
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Research on energy-saving optimization algorithm of urban rail train based on target speed tracking

SHA Miao, ZHANG Kexin, LIU Zhigang, QIU Ruichang, CHEN Jie

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In order to realize the energy-saving operation of urban rail transit, a research on energy-saving optimization algorithm of urban rail train based on target speed tracking is proposed. Firstly, the dynamic model of the homogeneous bar of the train and the objective function of energy-saving optimization are constructed, and the energy-saving operating conditions of the train are derived by using the maxima principle. After that, the impact of operating time and mode on operating energy consumption is analyzed. Based on the simulation analysis of typical schemes, the operation strategy based on the equivalent average velocity method at steep slopes and the rational use of idleness when the target velocity changes are proposed. The speed curve is solved by the target speed tracking method, and the energy-saving operation of urban rail trains is realized. A section from Tieli Road to Youyi Road of Shanghai Metro Line 3 is taken as an example, the results show that the algorithm designed in this paper can reduce the operating energy consumption by 25.39% compared with the actual operation situation. At the same time, the speed curve obtained by solving is gentler, which is more suitable for the actual operation of urban rail transit.
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Design and implementation of edge cloud based on intelligent control all-in-one machine

changhaili

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In view of the many business systems in subway stations, the traditional station systems are built in discrete mode, resulting in many station devices with low resource utilization, high energy consumption and large land area, etc. This paper adopts the modular design concept and CPCIe architecture combining European connectors and PCI Express signal commands and protocols to design miniaturized functional boards for computing, storage, switching and expansion, etc. Various boards are The various boards are mixed and inserted in a cage on demand to form an intelligent control all-in-one machine, which replaces the traditional servers, switches, storage, FEP, PLC and other equipment in the station, and on which an edge cloud is constructed to provide a resource platform for all business systems in the station. The edge cloud based on the intelligent control all-in-one machine is well applied in metro lines such as Kunming Metro Line 4 and Shaoxing Metro Line 1, which improves the efficiency of station resources use, reduces the number of equipment and room area, lowers energy consumption, realizes real-time data collection and sharing in stations, empowers smart stations and smart service systems, and helps metro high-quality development.
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Design and mechanical characteristics of double-ring supporting system for complex and irregular deep foundation pits

Liu Teng, Li Zhaoping, Wang Quanxian, Wang Jiahao, Cui Xiangyang

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The foundation pits on the third and fourth floors of Xinghuo Station on Beijing Metro Line R4 have characteristics such as complex plane shapes, different excavation depths at all levels, and asymmetric additional loads around the foundation pits. To address the issue of conventional foundation pit support schemes not being suitable for this foundation pit, a double-ring reinforced concrete internal support system with unequal diameters was developed and successfully implemented. This paper discusses in detail the layout, structure parameters and construction steps of the double-ring supporting system. A three-dimensional numerical calculation model is established to simulate the process of foundation pit excavation and supporting system construction, and combined with the measured results of deformation and stress of the double-ring supporting system, the stress and deformation characteristics of the double ring supporting system are discussed. The results show that the indicators of the double-ring supporting system, such as the deformation of the retaining wall, the axial force of concrete support and concrete ring beam, and the convergence of the concrete ring beam, all meet the requirements of the control value. The engineering practice shows that the reinforced concrete double-ring supporting system has the advantages of flexible layout, good adaptability to irregular spatial shapes of foundation pits, and spacious working space inside the foundation pit.
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Research and Practice on Design of Prefabricated Turnout Bed for Urban Rail Transit

liuguan, Lu Bin, Zhang Guangming, 冯家琦

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The cast-in-place turnout bed and turnout sleepers are discrete, and the assembly process is cumbersome and requires a long construction period. The existing prefabricated turnout track bed has complex structure, multiple construction procedures, and poor versatility. On the basis of the existing prefabricated turnout track structure, a new type of prefabricated turnout bed was proposed and developed, expounds the optimized design and research innovation in the aspects of plane profile, control dimension, rail bearing platform, limit structure, isolation/damping layer, and the reserved interface for the installation of the switch machine. This new prefabricated turnout track structure has been successfully implemented in the actual project. Compared with the existing prefabricated turnout structure, the production and construction convenience is significantly enhanced, and it has a very broad application prospect.
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Research on network security defense in depth system based on Urban Rail cloud

lushizhao, liukui, shadongqiang

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With the rapid development of the construction of urban rail transit information continues to develop rapidly, the severe international network security situation is increasingly. It is indispensable to accelerate the construction of a technically-advanced, manageably-efficient , safe and secure urban rail transit cloud network security system. Targeted at urban rail transit cloud netwok security, construct layer-protected defense system in depth and breadth from the aspects of technology and management. Combine the netwok security protection of cloud platform and application system with enterprise management, and protect Internet users personal privacy and enterprise’s data assets from the perspective of data security lifecycle. The zero trust technology system is applied in the urban rail cloud network to improve the use convenience of legal users while improving the threshold of illegal user intrusion and preventing illegal user intrusion. Facing multi-layer suspicious network attacks, it is a must to make sure the depth of network security has the defense adaptation, to restrict malicious and accidental destruction behaviors, to enhance the ability to identify potential security vulnerability instantly, to decrease national economic loss and information leakage of production information in full measure, and to further promote the foundation of network security defense in depth system.
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Study of the topology of power grid on the characteristics of stray current distribution in metro

WANG Wenbo, LI Wenheng

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The stray current intruding into the transformer is affected by the train operating conditions, rail-to-ground transition resistance, soil structure and grid topology, etc. Exploring the factors affecting the stray current is one of the important means to prevent and control the DC bias of power transformers around the metro. To study the influence of the grid topology on the stray currents intruding into the transformer, a dynamic coupling finite element model of the metro line and the grid circuit is constructed. Based on this model, the variation of stray currents in the intrusion transformer is analyzed for different relative positions of the single circuit of the grid and the metro line, under three typical topologies of the power grid structure. The results show that among the three structures, the radial structure is the most affected by stray currents, and the total amount of stray currents intruding into the grid increases with the increase of the number of grid loops. In addition, regardless of whether the two transformers forming the grid loop are on the same side of the metro line or on the opposite side, the stray current intruding into the loop increases as the angle between the metro line and the grid loop decreases.
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Risk evaluation of waterlogging in subway stations based on comprehensive weighting-VIKOR method

CHEN Zi, MA Weilang

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In order to effectively prevent and reduce the occurrence of waterlogging accidents in subway stations, A risk evaluation model of waterlogging in subway stations based on comprehensive weighting-topsis method was put forward. Firstly, The evaluation index system of waterlogging risk in subway stations was populated, which was consisted of five aspects: rainfall, water retaining capacity, drain capacity, safe evacuation and safety management. According to the game theory, the weights obtained by analytical hierarchy process and CRITIC methods were optimized and recombined to obtain the comprehensive weight. Finally, the benefit value of VIKOR method is applied to determine the waterlogging risk level of the subway station. The model was applied to the waterlogging risk assessment of Guangzhou Metro Line 13, and the waterlogging risk grade and ranking of each subway station are obtained. The results show that the waterlogging risk level of Nangang station is high, Ensure the safe operation of Metro in flood season by formulating targeted measures and targeted measures are formulated to ensure the safe operation of the subway station in flood season. The evaluation results of this method are consistent with the actual situation, providing a new method for the waterlogging risk evaluation of the subway station.
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Research on Mechanism Guarantee and Realization Path of Urban Regeneration Promoted by Rail Transit TOD: A Case Study of Futako-Tamagawa Station in Tokyo

Zhu Dan, Liu Lihong, Rong Chaohe, Wang Dapeng

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Rail transit TOD-oriented urban regeneration is an important path to achieve effective renewal of megacities. This paper analyzes the characteristics of Tokyo rail transit TOD promoting urban regeneration and development from three aspects: institutional characteristics, subject characteristics and renewal law, and takes the redevelopment project of Futako-Tamagawa Station in Tokyo as an example, so as to provide experience and reference for urban renewal under TOD mode in mega cities in China. This study finds that in the renewal of Japan's rail transit TOD stations, the government delegated the power of planning, development and land use to the market by entrusting the redevelopment organization with the main body of the track as the core, and the redevelopment organization carried out the project design and project development. By designating the redevelopment area as "redevelopment promotion area", relaxing the floor area ratio restriction in the redevelopment area, encouraging the track subjects to participate in the construction of public space and obtain higher development intensity, promoting the maximization of land use value and achieving the balance of interests of the participants.
1
Li Ying,Zhang Bawu

LiYing

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In the existing line reconstruction project of vehicle expansion and platform extension, it is inevitable that small radius curves will enter the platform due to the limitation of surrounding engineering conditions. Under the design concept of conventional curve superelevation, the intrusion of small radius curves into platforms will result in speed limits. The design concept of drawing inspiration from highway curve superelevation is proposed. The curve superelevation is set in local sections of the transition curve, and the full superelevation section is set at gentle points or circular points. By segmenting the transition curve along the slope, the speed limit problem caused by excessive entry of small radius curves into platforms is solved. On this basis, taking the extension of Zhichunlu Station in the capacity expansion and upgrading project of Beijing Metro Line 13 as a case, the renovation plan, which drew inspiration from highway design ideas, increased the maximum speed by 12.4km/h compared to the conventional plan and saved 6 seconds of operating time.
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Construction of a Case Base for Subway Engineering Accidents and Risk Assessment Analysis

LYV Peiyin, WANG Yali, MA Xiao, LIU Faming, SHAO Feihao

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An extensive case base of over 2000 accident cases and corresponding economic loss data have been collected from the last 20 years of domestic subway construction. This has resulted in the establishment of the largest database for subway construction accidents to date that is continuously updated. Based on this database, a quantitative risk level standard, accident statistical analysis, prediction and risk estimation calculation model have been developed. Project area, construction method, and operation type are some of the conditions used in estimating the probability of accidents, the resulting economic loss, and risk level. This solution also effectively determines the quantitative safety risk assessment of subway projects and loss rates within the engineering insurance industry. A query-based quantitative safety risk assessment system has been developed using engineering accident cases that can perform statistical analysis, deduction, and prediction of a specific accident type by region, city, line, construction method, and accident type. The system has been successfully applied in engineering safety risk assessment and insurance projects in over 20 cities currently under construction.
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Application of Comprehensive Geophysical Prospecting Technology in the Bedrock Section of Shield Tunnel

CHEN Da, LIU Jing, wangyidong

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In order to investigate the distribution characteristics of various adverse geological effects in the shallow buried section of shield tunnel bedrock, a comprehensive geophysical exploration technique was employed, including high-density resistivity method, shallow seismic reflection wave method, and micro-tremor exploration method. The anomalous geological conditions such as the depth of bedrock, fractured and fragmented zones, and isolated stones were detected and studied. By comparing and analyzing the results of the three geophysical methods and combining them with drilling and geological investigation results, the complex strata were effectively divided, and targeted suggestions were proposed for the selection and design of tunnel shield and construction measures.
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Research of Influence Rule of Track Damping Structure on Steel Truss Bridge Noise

FANG Bin, ZHANG Hongliang, DUAN Yuzhen, LI Xiaozhen, ZHANG Guangming, lianglin

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The noise radiation problem caused by the train passing through the steel bridge is more prominent than that caused by the concrete bridge, which has a greater impact on the residents along the line. Establishing a Prediction Model for Structural Noise and Wheel Rail Noise of Steel Truss Bridges Based on Statistical Energy Analysis (SEA), analyzed the noise impact and propagation law of four different types of track vibration reduction structures, including general integrated track bed, damping pad floating slab track, rubber spring floating slab track, and steel spring floating slab track, on the pedestrian system and surrounding sensitive field points of the steel truss bridge, the comprehensive noise of the pedestrian system and sensitive points are predicted. The research conclusion provides a basis for the design and selection of track vibration reduction structures on steel truss bridges, and it provides reference for solving bridge noise problems in similar projects in the future.
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Wang Chen 1 SHI Jungang1,* Xi Sulu2 Bao Jiayao2

Wang Chen, Shi Jungang, Xi Sulu, Bao Jiayao

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In order to meet the demand for meticulous passenger transportation organization in urban rail transit stations, it is necessary to classify and manage stations based on the characteristics of entrancing and exiting passenger flows. Based on the entrancing and exiting passenger flows data collected by AFC, this paper proposes a two-layer planning clustering method based on the K-means algorithm to cluster and classify all stations on the entire line from the two aspects of the total amount of passenger flow and the temporal characteristics of entrancing and exiting passenger flows. Firstly, the upper-layer clustering is carried out based on the total amount of passenger flows of entrancing and exiting as the characteristic indicator, and different types of stations with different passenger transport scales are obtained. Then, considering the temporal characteristics of entrancing and exiting passenger flows, the feature vector is constructed according to the characteristics of passenger flow changes in different periods for lower-layer clustering to identify the temporal distribution characteristics of passenger flow in the station. The classification results are highly consistent with the actual situation, and there are significant differences in passenger transport scale and temporal characteristics among stations of different categories. It can be seen that the proposed two-layer K-means clustering analysis algorithm can well grasp the passenger transport scale and temporal characteristics of passenger flow providing a basis for the passenger transportation organization of stations.
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Analysis of the Characteristics of Transformer Bias Current Caused by Metro

ning xiao yan, Xiao Song, Guo yu jun

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With the rapid development of urban rail transit, the DC magnetic bias of surrounding power transformers becomes more and more serious. The magnetic bias current invading the transformer mainly includes stray current and induced current. This paper first explores the electromagnetic coupling mechanism between the power grid circuit and the metro traction power supply system, and uses CDEGS and PSCAD software to build the electrical coupling and magnetic coupling simulation models respectively, so as to analyze the time and frequency domain characteristics of stray current and induced current invading the power grid circuit. It is found that the coupling current is low-frequency time-varying current, the current frequency domain is concentrated in the 0-0.05Hz frequency band, and the pure DC component in the stray current accounts for more than the induced current. In addition, the influence of the number of trains running on a single line, train operating conditions and other factors on the distribution of magnetic bias current in the circuit is also explored.
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Consideration on the network and operation characteristics of suburban railway in Seoul Metropolitan area

chunbinhu, lou dong, 吴海卫

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Firstly, the paper briefly introduces the composition of rail transit network in Seoul metropolitan area, which can be divided into suburban railway, subway and light rail. Secondly, the paper summarizes the characteristics of suburban railway network in Seoul metropolitan area from three aspects: through operation of subway, interconnection of existing lines and diversification of operating subjects. In addition, it summarizes the operating characteristics of suburban railway in Seoul metropolitan area from fast and slow line operation, passenger flow index and economic index. The experience and lessons of suburban railway in Seoul metropolitan area have certain enlightenment for the construction of suburban railway.
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Research on grade evaluation and regional station division method of urban rail transit

Dong yunzhou

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The concept of urban rail transit station grade is mostly used in the planning of urban rail transit network. It usually takes the prediction of peak hour passenger flow and daily passenger decline as the main evaluation indicators. That is more inclined to the consideration of project cost and project volume. It is rarely used in the operation and management of urban rail transit station. However, the rating work of urban rail transit station is the basis for the fine and standardized management of urban rail transit operating units, as well as an important reference for resource allocation of urban rail transit operating units. The author builds a station grade evaluation system，including passenger volume index, railway traffic index and service index, objectively reflects the operation volume of each station。This system makes station grade evaluation systematic, scientific, quantifiable and operable. It makes up for the deficiency of qualitative analysis in many evaluation works. In this paper, the research results are applied to the stations of Chongqing Rail Transit Line 1 and Circle Line, all the stations are graded and the quantitative calculation results are applied to the division of regional stations. The actual calculation proves that the research results are in line with the operation status of Chongqing rail transit. It has the characteristics of reducing the management structure and balancing the workload of each regional station. The results of this study have a strong guiding significance for the operation and management of urban rail transit operation stations. It also can provide decision support for subsequent resource allocation, personnel allocation, emergency treatment, performance evaluation and other work of management.
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Research on the Impact of Disassembly and Reconstruction of Guangzhou Metro Line 3 on the Passenger Flow

tangqing

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In order to study the future evolution trend and pressure relief method of passenger flow of Guangzhou Metro Line 3, this paper first analyzes the current passenger flow characteristics of Line 3, and discusses the possibility of optimizing its Y-shaped traffic plan from the perspective of transportation organization. Then, based on the proposed disassembly ideas for Line 3 and Line 10 in the line network planning, this paper analyzes the impact of whether to disassemble Line 3 on passenger flow under different rail network supply conditions in the future by using Guangzhou Urban Transit Model. The results show that: (1) At present, the passenger flow pressure of Line 3 has little room for optimization at the level of transportation organization. In non-disassembly situation, Line 3 will still face greater passenger flow pressure in the next few years. The maximum section full load rate of the north extension line of Line 3 will reach more than 140 %, and the maximum transfer volume of Tiyu Xilu Station will exceed 600,000 passengers / day. However, with the recent opening of parallel lines, the passenger flow pressure will gradually ease; (2) If Line 3 will be disassembled, the transport capacity of the northern section of Line 3 will be improved, the passenger flow pressure of the peak section will be quickly alleviated, and the maximum transfer volume of Tiyu Xilu Station will also be lower than the maximum before the COVID-19 epidemic, but there will be some negative effects during the disassembly period. Therefore, the impact of passenger flow before and after disassembly and the social impact during disassembly should be comprehensively considered to determine whether Line 3 will be disassembled and reconstructed in the future.
1
ZHANG Jinxun1, LI Bo1, JIANG Yusheng 2, ZHOU Liugang1, JIANG Hua2, YIN Minglun1,3, SUN Zhengyang1,3(1. Beijing Urban Construction Group Co., Ltd., Beijing 100088;

Zhang Jinxun, LIBO, Jiang Yusheng

Abstract: (266) HTML (0) PDF (0.00 ByteKB) (0)

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Complex hydrogeological conditions of sandy and cobble strata are a major obstacle to efficient shield tunneling. The common engineering problems of shield tunneling in sand-pebble stratum were summarized, and four formation characteristic factors that restrict the efficient tunneling of shield tunneling were put forward, which are particle size, fine particle content, water pressure and abrasion performance, and the characteristic index, index determination method and index quantization interval of each factor were given, according to which the sand-pebble stratum can be classified. The classification results include: transportable and non-transportable sand cobble stratum by particle size, high viscosity low permeability and low viscosity high permeability sand cobble stratum by the proportion of fine lens, high pressure and low pressure sand cobble stratum by high pressure and low pressure water pressure sand cobble stratum, strong and weak abrasion sand cobble stratum by equivalent quartz content. Based on different strata categories, a reasonable shield scheme was matched. Finally, the applicability of the classification method was verified by the shield example of sand and pebble strata under the combination index. The design and construction of sand-pebble formation shield can be guided by the classification method of sand-pebble formation.
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Research on Time-frequency Characteristics and Corrosion Behavior of Dynamic Stray Current

Xia Xue, Yang Xiaofeng

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In DC traction power supply system of urban rail transit, partial return current from running rails may leak to earth and form stray current, which can easily cause electrochemical corrosion of buried metals. Stray current would appear as nonstationary signal due to the frequent start and stop of multiple trains in actual system, while its time-frequency characteristic is conducive to the study of its corrosion behavior. Based on the mathematical model of traction power system, time-frequency analysis of stray current signal has been conducted through S-transform. Furthermore, corrosion behavior of stray current at typical frequencies have been studied based on weight-loss test and electrochemical test. The experimental results show that both DC and low-frequency AC components of dynamic stray current will affect the electrochemical corrosion process of metals, and the corrosion rate rises with the increase of current density and the decrease of AC current frequency.
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Comprehensive benefits evaluation system and application of coupled grey-green infrastructure system on metro depot

Lyu Jiajie

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Based on the characteristics of metro depot, a grey-green coupled rainwater system evaluation system is built which is focused on environmental, economic, engineering and social factors. Grey-green coupled rainwater system refers to the coupling use of grey storage facilities and sponge city measures, which is the emerging direction of rainwater regulation and storage. The runoff reduction rate, flood peak reduction rate, construction difficulty, rainwater resource utilization and construction cost were selected as evaluation indexes. The analytic hierarchy process and entropy weight method were used to determine the index weights, and the comprehensive benefit evaluation system was constructed based on the cloud model, which is expected to provide reference for the gray green measures evaluation of the design and operation stage of metro depot. The evaluation system was applied to the yuhuazhai depot of Xi'an Metro. Finally, a total of 58 schemes were established. The results showed that the performance of grey-green coupling scheme in the depot was better than the grey measures or the green measures.
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Disaster resilience assessment of urban rail transit systems under public health emergencies

HUO Xiaosen, SHU Xinyu, JIAO Liudan

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To promote the disaster resilience level of urban rail transit system in China, this study analyzes the characteristics of public health emergencies and explores the disaster resilience of urban rail transit system based on the context of public health emergencies. The evaluation system of disaster resilience of urban rail transit system is constructed from three aspects: emergency handling capability, passenger management capability, and public management capability. The subjective and objective weights of indicators are calculated by AHP and entropy weighting method, separately, and the combinatorial optimization is combined with the linear weighting method to obtain the final indicator weights. On this basis, the comprehensive evaluation model of extensive cloud resilience level is established to calculate the level of disaster resilience of the rail transit system in the face of public health emergencies. Taking Chongqing urban rail transit system as a model application, the feasibility and applicability of this model in the evaluation of disaster resilience of urban rail transit system are verified. The results show that the overall level of disaster resilience of Chongqing urban rail transit system under the impact of public health emergencies is good, but the resilience level of secondary indicators is medium including the control degree of epidemic public opinion management, the knowledge reserve degree of passenger epidemic prevention, and the reasonable degree of revenue and expenditure management, and the disaster resilience and recovery ability is weak. Analyzing the reasons for the low resilience level and taking a series of measures can effectively improve the resilience level of urban rail transit system under public health emergencies.
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Spatiotemporal characteristics of coordinated development of urban rail transit stations and built environment

huangyoudan

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It is significant to realize the coordinated development of urban rail transit and built environment since it can help to alleviate traffic congestion and optimize urban land use structure. Taking urban rail transit stations in the main area of Xi’an as a case, this paper evaluated the coordinated development status of urban rail transit stations and the surrounding built environment between 2018 and 2019 by establishing the node-place model. This paper visualized and analyzed the spatial and temporal variation characteristics of the coordinated level of the stations. The results show that the coordinated level between urban rail transit stations and the surrounding built environment is gradually decreasing from the central ancient city area to the surrounding regions in space, and presents a two-level differentiation trend in time. In most station areas, the traffic and the built environment are in a state of coordinated development. According to the change of their synergistic relationship, the stations are classified into three types: dynamically balanced stations, “low node-high node” dynamically balanced stations and “dynamically balanced-node imbalanced” stations. The improvement of station accessibility will significantly increase the node value and the place value, and the growth in node value is greater than that of the place value. The results of this paper can provide decision-making references for optimizing the station planning in Xi’an and promoting the coordinated development of urban rail transit and built environment.
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Cross-line Train Service Planning Optimization in Urban Rail Transit Network

chenlei, duanxiaoyu, baiyun

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Under the background of the expansion of urban rail transit scale and growth of passenger flow demand, aiming at the problems of many passenger transfer times and low resource sharing caused by the existing single-line operation mode, the optimization of cross-line operation scheme is studied to make up for the above shortcomings. In this paper, the alternative set of cross-line routing is generated according to the basic conditions on cross-line operation from the perspective of facilities, the number of cross-line and the demand of cross-line passenger flow. The departure frequencies of cross-line routing and local routing are taken as the decision variable. Considering the constraints of line capacity, train full load rate and total number of train routing, the passenger flow distribution of OD passenger group is carried out on the principle of minimum transfer times and shortest travel time. The optimization model at the network level on cross-line train operation plan is established to minimize the sum of train operation cost and passenger travel cost. Simulated annealing algorithm is applied to solve the model. Case studies on Nanning subway network show that the cross-line operation mode can reduce the total cost by 6.18 %, the passenger time cost by 7.33 % and the passenger transfers times by 13.79 % in comparison with the single-line operation mode. The results achieved cost savings, improved network service quality and passenger travel efficiency.
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Research on Line Position Scheme of Multi-function Express Rail Transit——Taking Xiamen line 9 as an example

TianFei

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In order to meet the requirements of rapid travel in metropolitan areas and quantitatively study the function and position of the multi-function line, a macro to micro analytical theoretical system of "circle layer - structure - corridor - along" is proposed.Taking Xiamen Metro Line 9 as an example, this paper analyzes the urban circle, establishes the accessibility model and spatial syntax model based on traffic situation, and determines the line"s bearing function.On the basis of function, the research on the competition and cooperation relationship of various ways along the corridor, the grouping classification along the corridor, and the coverage demand along the corridor is further refined, and the appropriate speed target value, line location scheme and operation scheme are finally determined.The results show that, in the preliminary analysis, the spatial quantitative analysis method is introduced, and the determined function of Line 9 composite express line can achieve the goal of Tongan fast access to the island, while taking into account the coverage along the line.
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Study on the influence of subway rail cant deviation on rail corrugation and its adjustment design

ZHAO Lei

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Aiming at the problems of rail damage, out-of-tolerance rail cant, abnormal rail corrugation, and out-of-standard noise in the subway short sleeper monolithic bed curve section, from the perspective of adjusting the track geometry and restoring the normal contact state of the wheel and rail, the track research on the cant adjustment design, and formulate the optimization and fine adjustment transformation plan of the line alignment. First, the out-of-tolerance test of the rail cant of the short sleeper monolithic bed in the curvilinear section was carried out, and the results showed that the out-of-tolerance rate exceeded 95%. By establishing a vehicle-track dynamic model, the influence of the rail cant on the wheel-rail contact relationship and rail corrugation was analyzed, and the adjustment of the rail cant and the design of the high-density polyethylene rail downhill pad were carried out, and the limit points were added to prevent the backing plate jumps out; the lateral stiffness of the fastener in the curve range was increased by the method of "adjusting parameters and ensuring stability", and the rail cant was adjusted, and the wheel-rail contact and the lateral stiffness of the rail were significantly improved. Before and after the adjustment of rail cant, the vibration acceleration of the rail, the ballast bed and the tunnel wall has been reduced, and the light band has been improved.
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Calculation Method for Train Headway of Regional Rapid Rail Transit

GAO Guofei, DU Gangde, Ju xing, Zheng Han

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Based on the train control method and transportation organization mode of regional rapid rail transit, this paper integrated the influencing factors such as train length, running speed, braking distance, safety protection distance, station operation time, etc. Drawing from the idea of calculating high speed railway train interval, the type and definition of train interval time for regional rapid rail transit were summarized, and a calculation method for various interval times under different crossing conditions was proposed. The results indicate that the tracking interval is 45~52s, the additional time of starting is 22~56s, the additional time of stopping is 19~46s, the arrival-though interval is 45~51s, the though-departure interval is 18~19s. Compared with the results calculated by OpenTrack, the average error of theoretical calculation result is 0.21. The proposed calculation method for train interval time provides a reference basis for selecting key parameters in the transportation organization planning process of urban rapid transit systems based on train control and organization modes.
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Spatial Evolution Characteristics and Planning Strategies of Chengdu-Dujiangyan Railway Station Area

GAO Yanan, CUI Xu, FEI Ningyuan, 梁朋朋, 冯会会

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Suburban railway is an important support for long-distance travel in the metropolitan area, and the spatial development status of station area is related to the efficiency of rail operation and the improvement of spatial efficiency of the metropolitan area. Based on the analysis of the passenger flow activities and the spatial-temporal changes of land use in the Chengzhou-irrigated high-speed rail from 2010 to 2021, it is found that: Suburban hub stations have the fastest passenger flow growth and land renewal change, while endpoint stations have large passenger flow but slower spatial development. In general stations, the suburban stations within 10-25km from the urban center have a relatively fast growth in land use, but the stations with a large proportion of logistics and industrial land have a less obvious spatial change. The spatial evolution direction of the station area has inward-oriented, Isolated development, Single-sided padding, and multi-directional group development models. The factors affecting the spatial development of station area mainly include station location, connection and transfer conditions, type of station area and surrounding resources, etc. Finally, according to the characteristics of passenger flow demand and development rules of different types of stations, the paper puts forward specific planning suggestions for hub station, endpoint station and general station.
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Engineering Practice of Shield Cutting Reinforced Concrete Piles in Soft Fluid-Plastic Stratum

LIAO Qiulin, SONG Yuejin, FANG Jianhua, YANG Hao, ZHAO Lian, CHEN Zihao

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For the aim of shield cutting large-diameter reinforced concrete piles in soft fluid-plastic stratum, the subject based on the Shaoxing subway line 2 to analyze shield type selection, parameter control, mechanism of cutting rebar and concrete, and tool wear. The main conclusions as follows: (1) MJS construction method and three layers tearing cutter method finished the job of pile cutting. (2) the principle of pile cutting parameters control with “low propulsion speed, medium rotate speed, small shield torque, strict grouting, advanced strength supplement, frequent measurement” is suitable for soft fluid-plastic stratum. (3) Three forms of rebar destruction are shear-stretch, bend-stretch, and pure shear, and the pile cutting target had achieved of shear-stretch and bend-stretch destruction form occupy 47% and 25% respectively. (4) Rebars were convolved the shield disk where the blade holes of shield center and tracks of radius R≤2025mm, and most of these rebars lower than 3 meters with bend-stretch destruction. (5) R=2500mm is critical track of cutter destruction, and cutter breakage rate and dimension will increase significantly with the increasement of track radium. (6) Based on the tearing cutter states, only one full section engineering pile can be cutted.
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Study on structure configuration and mechanical properties of assembled integral segments of shield tunnel

JIA yonggang, Wu Fan, 鲁卫东

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The traditional segments of shield tunnel consist of segment pieces and bolts, the large number of segment joints can reduce the overall stiffness and deformation resistance of the segment structure. Moreover, the long-term operation also caused problems such as rusting of bolts and water leakage, which seriously affected the safety of the tunnel structure. An assembled integral segment was presented in this paper, the new segment structure included T-shaped segment pieces and post-cast concrete. The T-shaped segments were erected during shield TBM tunnelling, and the erection method was the same as the traditional segments. The post-cast concretes were constructed after the tunnel breakthrough. Based on ABAQUS software, the mechanical properties of the new segment structure and the traditional segment structure were compared using the load-structure method. The results showed that the new segment structure can meet the tunnel structure design requirements during the construction stage. During the tunnel operation stage, the T-shaped segments and post-cast concrete worked together to bear the tunnel load. The post-cast concrete provided effective protection to the T-shaped segments due to its higher stiffness. The assembled integral segments structure can effectively enhance the integrity, stiffness and deformation resistance of the tunnel structure, and the mechanical properties are better than the traditional segments. In addition, the new segment structure also has a protective effect on the segment joints and bolts, offering a new technical proposal for urban rail transit construction.
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Discussion on application of refrigerant pump assisted multi-connected air conditioner for data centers in subway equipment rooms

王奕然, 孙翼翔, 郭温芳, 祝岚

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Aiming at the common problems of ventilation and air-conditioning system in equipment rooms of subway stations, on the basis of systematic analysis of the current situation and challenges, combining with the development trend of air conditioning in the field of data center–refrigerant pump assisted multi-connected air conditioner, the application scheme of this technology in equipment rooms of subway stations is put forward. Furthermore, standard underground station in a city in north China is taken as an example. A comprehensive technical and economic comparison is made with the traditional scheme. The analysis results show that the scheme has technical advantages in improving room temperature control effect, saving operation energy, ensuring air quality, matching load characteristics, facilitating construction, operation and maintenance, reducing control difficulty and so on. Although the initial investment of the scheme is about 700,000 RMB higher than that of the traditional scheme, the operation cost is about 227,000 RMB lower than that of the traditional scheme. The payback period of the static investment is about 3.1 years, which has a good economy.
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Application analysis of wall evaporative condensation direct expansion refrigeration system in Hefei Metro

作者彭铁红, 姜新杰, 方黄志

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The cold source needed for air conditioning and refrigeration in subway stations is generally obtained by the traditional form of "water chiller+cooling tower". The cooling tower itself is bulky, occupies a large area, has serious noise pollution, and it is difficult to coordinate land acquisition and demolition, which is not conducive to the planning and construction of the subway and the development of the city. Air-wall evaporative condensation direct expansion refrigeration system does not need to install cooling tower equipment on the ground, and has the advantages of energy saving and noise reduction, low demolition difficulty and low construction investment cost. However, the new system has some defects, such as high initial investment cost, limited application scope and high operation and maintenance cost, so it cannot be applied in a large area. Taking Sanxiaokou Station of Hefei Metro as an example, this paper introduces the working principle, installation mode, operation energy efficiency evaluation, advantages and disadvantages of the new system, and analyzes the construction cost, energy saving and noise reduction, feasibility and so on. The new system has obvious advantages in social and economic benefits, energy saving and noise reduction, demolition coordination, construction cost, land resource utilization and so on, and has broad application prospects.
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Study on deformation law of foundation pit connecting Beijing Subway and ground

zhujianxun, yangchunyang, 罗正高, 郭涛

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For the study of Beijing subway even wall stress deformation characteristics of foundation pit, using statistical methods for during the period of "much starker choices-and graver consequences-in" in Beijing subway analyzes the deformation monitoring data, and according to the thickness of palisade structure and type of the wall of foundation pit supporting system are classified, it is concluded that the different types of foundation pit surface, wall, the deformation law of lattice column and foundation pit settling tank curve. The results show that :(1) surface uplift accounts for a large proportion of the surface deformation of foundation pit, and the types of supporting system and the thickness of enclosure structure have different effects on the surface deformation; (2) According to the direction and amplitude of wall top deformation, the wall deformation is divided into four types. The influence of excavation depth on wall deformation is greater than the positive effect of increasing the thickness of enclosure structure. (3) The deformation law of the wall top is mainly upward, accounting for more than 90% of the statistical data; (4) The deformation of lattice columns is also dominated by uplift, which is larger than that of the wall top.
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Co-construction Technology of Positioning System and BIM Model for Foundation Pit Engineering

YAN Haisheng, 吕培印, 唐明明, 刘淼, 王晓宁

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The requirement of safety management of urban rail transit engineering construction is high, more and more advanced techniques are used for the safety management of the construction site. Among them, BIM modeling and personnel positioning systems are widely used in open-cut foundation pit engineering. However, when the two-dimensional spatial positioning data of personnel based on UWB positioning technology are superimposed into the three-dimensional model, due to the different dimensions, the data can not be matched in three dimensions. In order to solve the problem of data matching, relying on the foundation pit project of Beigangzi Station of Beijing Metro line 12, Through layered modeling of Earthwork Model of foundation pit, and the relationship between X-direction independent variable and Z-direction dependent variable of personnel model is created, the earthwork model is excavated layer by layer with the construction progress, and the Z coordinate of the personnel model is dynamically consistent with the surface layer of the earthwork model, and the three-dimensional co-construction of personnel location and BIM model is realized, So as to realize the fusion display of positioning data on the BIM model. the three-dimensional co-construction technology is applied and verified through the actual project, providing example reference for other similar three-dimensional co-construction projects.
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Construction and application of safety risk monitoring platform for urban rail transit project construction

MI Baowei, WANG Shuming, ZHANG Qiang

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In order to improve the overall efficiency of safety management, improve the level of safety management informatization, and realize scientific decision-making and precise policy implementation of management and control, Qingdao Metro has established an integrated safety risk monitoring platform, which integrates risk management, hidden danger investigation and management, shield/TBM monitoring, education and training, emergency command management, on-site video surveillance and other major business systems, it fully develops the superiority of big data, completed the data sharing between the business and connectivity, and improve the efficiency of production safety management. The article introduces the advantages of the integrated platform, the key functions and functions of each system, and the coordination and linkage with the system mechanism. It provides information for the updating and upgrading of multi-line network subway construction reference and guidance.
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Evaluation method of safety status of subway foundation pit based on multi-information fusion

ZHANG Hao, LU Pei-yin

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According to the monitoring items of the supporting structure of the foundation pit project and the surrounding rock and soil mass, the monitoring objects of the foundation pit project are divided into the ground settlement type, the retaining structure type and the internal support type; On the basis of monitoring and early warning classification standards, the early warning standards of the above three types of early warning are determined through a large number of accident case data and foundation pit deformation mechanics relations. At the same time, the three types of early warning within the scope of early warning correlation analysis are fused, and entropy weight theory and interval number are introduced to evaluate the safety state of foundation pit. This method realizes the fusion of multi-source engineering monitoring data, objectively and rapidly evaluates the safety status of foundation pit, avoids the incomplete and inaccurate problems of single index early warning and artificial judgment of the safety status of foundation pit, and provides reference for the rapid and accurate judgment of the safety status of deep foundation pit.
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Study on risk assessment of ultra-shallow buried shield tunnel crosses the existing line closely

ZHANG QIANG, 米保伟, 鲁棣源, 王术明

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How to evaluate the impact of new tunnel on the existing line and what measures are taken to ensure the safety of existing line structure, are the main problems facing the near construction. Qingdao Metro Line 6 Efu section shield tunnel crosses the existing Line 1 Eshi section tunnel project, which has the characteristics of ultra-shallow buried, soft up and hard down formation, crossing the existing line closely. Through the finite element calculation, analyzed the influence of shield construction on the structural deformation of Eshi section tunnel , and studied the risk control countermeasures of shield construction. The result shows that the structure deformation of the Eshi section caused by the shield construction of Efu section is small. Through comprehensive control countermeasures including stratum pre-reinforcement, test section first, automatic monitoring, the shield crosses smoothly. During the process, all the displacement values of the Eshi section tunnel structure are normal, and the maximum displacement value is about 1mm, 1.5 times of the calculated value. The research result can provide a reference for similar projects in the future.
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Research on temperature gradient effect of U-beam in rail transit

TIANYU

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In order to study the temperature gradient effect of U-beam in rail transit.The temperature monitoring and results of U-beam in existing domestic projects are collated and summarized,in parallel with the temperature load in the current railway code and conventional practice, and combined with solid finite element model calculation, the temperature stress and deformation of U-beam under different temperature gradient modes are obtained.The longitudinal normal stress value of the U-beam under the gradient temperature load condition accounts for a relatively large proportion of the normal stress value, while the transverse stress and local deformation difference are relatively small.Finally,the temperature gradient mode suitable for U-beam is proposed when the trend of the rail transit line is roughly east-west, the vertical temperature gradient of web is an exponential function, and the vertical temperature gradient of bottom is a broken line function,and the conclusion can provide reference for relevant engineering design.
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Experimental study on aerodynamics of 80 km/h B-type subway train running in tunnel

liyang

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In order to investigate the aerodynamic effect of the 80km/h B-type subway train running in the tunnel, the aerodynamic test was conducted in a fully underground line with a tunnel diameter of 5.4m in Nanning using the real vehicle test method, and the fluctuation of air pressure inside and outside the train and the comfort of ear pressure inside the train during the tunnel operation were analyzed. The research results show that: when the train passes through the middle air shaft position in the tunnel at 80km/h, the pressure fluctuation inside and outside the train is drastic, and the maximum values of peak to peak values outside and inside the train are 1452Pa and 923.4Pa respectively; when the train has drastic pressure fluctuation inside and outside the train, the pressure difference between each measurement point outside the train is large, and the pressure difference between each measurement point inside the train is small, the mean square difference of the peak to peak values outside the train is 9.6 times of the mean square difference of the peak-to-peak values inside the train; the ear pressure comfort is good when the train is running in the non-wind shaft area, but there is a risk of passengers' ear pressure discomfort when it is running in the wind shaft area. The results of the study can provide reference for the evaluation and improvement of the ear pressure comfort of 80 km/h speed class metro train.
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Research on EUHT-5G Redundant Networking Scheme for Urban Rail Transit

geshuyun, lihuijuan

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EUHT-5G communication technology has the advantages of high bandwidth, low latency, high stability, and low power consumption. It is a new generation of ultra-high speed mobile communication technology that can be applied to urban rail transit, and has been commercialized in Guangzhou Metro and Beijing Metro. By studying the service and frequency planning scheme of EUHT-5G system, this paper analyzes the redundancy schemes of center layer, access layer and power supply based on the architecture of EUHT-5G system. Through the redundancy scheme analysis, the paper provides a reference basis for the urban rail transit car ground wireless transformation or new project EUHT-5G redundancy networking.
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Statistical Analysis of Urban Rail Transit Operation in theWorld in 2022: A Review

Xi Zhe

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The article summarizes the statistics for 2022 on operation of urban rail transit systems in the world, which are classified into metro, light rail and tram systems in line with the widely accepted international standards. The statistics show that 545 cities in 78 countries or regions worldwide have hosted urban transit systems by the end of 2022, with the total length reaching 41,386.12 kilometers, among which, the metro system accounts for 48.9%, the light rail 9.8% and the tram 41.3%. Urban rail transit systems have been built and put into operation in 61 Chinese cities (including Hong Kong, Macao and Taiwan) and the total length in operation has reached 10857.17 kilometers by the end of 2022, of which 10,291.96 km was in operation in mainland China. The ridership of metro and light rail worldwide totals 49.87 billion trips in 2021, with an average of 7400 trips per day, including 25.69 billion passengers in China. It is found that China ranks the first in the world in terms of the size and ridership of its urban rail transit system networks. According to the statistics of domestic suburban railway lines, the operating length is more than 2954.67km, and the length under construction is more than 2826.91km. Suburban railways will provide strong support for the development of metropolitan areas and city clusters, make positive contributions to the realization of the "dual carbon" vision, and lay the foundation for the construction of a transportation power.
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The Theory And Practice of Assembling Integrated Underground Station

huzhengbo

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At present, there is little research on the theory and key technology of how to realize the assembly of underground station with inner supporting foundation pit in the soft soil and water rich area in China.This paper studies the problems such as the architectural integration of the assembled and laminated integrated underground station, the stress of components and nodes, the seismic performance, waterproofing and applies them in the South Gate Station of the Wuxi Jiangyin Intercity Rail Transit Project.The results show that the research of architectural integration can realize the integration of structural system, equipment and pipeline system, interior decoration system and promotes the quality improvement of prefabricated underground stations.The composite structure of station slab, wall, beam, column and other components can meet the stress requirements of construction and use stages. The composite structure type of assembled and laminated integrated underground station can meet the seismic performance requirements of moderate and large earthquakes.The research on self waterproofing, external waterproofing and joint detail waterproofing of concrete structures can meet the requirements of waterproofing design and use in underground stations.The design theory and key technology of the assembled and overlapped integrated subway station are presented, which can provide reference for the application of the assembled and overlapped technology in the construction of the assembled structure of the underground station.
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Statistical Analysis of Urban Rail Transit in mainland China in 2022

HouXiufang

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.By the end of 2022, 55 cities in Chinese Mainland have put into operation more than 10000 km of urban rail transit lines, reaching 10291.95 km. Among them, the subway line is 8012.85 km, accounting for 77.85%. In 2022, 5 new urban rail transit operation cities were added, and the total length of new lines was 1085.17km, including 803.12km of new subway lines. The new lines involve 4 types of systems, distributed in 25 cities, with a total of 50 lines (sections).
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Research Status and Future of Virtual Coupling Train Technology

YANG Zhongping, YOU Ting, SHU Tiancheng, LIN Fei, and FANG Xiaochun

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The virtual coupling train technology based on vehicle-to-vehicle wireless communication can flexibly and accurately match transport capacity according to the temporal and spatial changes of urban rail transit passenger flow, improve the quality of transport services, and enhance the efficiency of transport capacity utilization. This paper firstly introduces the development process of virtual coupling technology, expounds the key technologies required to realize virtual coupling technology, then review the research status of virtual coupling technology in three aspects: operation control, communication, and transportation organization, and finally looks forward to the application prospects of virtual coupling in urban rail transit.
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Exploration and practice of green and low carbon constructionof Shenzhen Metro Line 6

Zhou Chao

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The urban rail transit in China has been developing rapidly and the growing trend is expected to continue. Meanwhile, practical problems of the increasing construction costs, incremental pressure from energy consumption and carbon emission reduction are nonnegligible. Bearing the goal of sustainable development, Shenzhen Metro Line 6 advocates the new concept of green and low-carbon construction, through the innovative application of technologies not limited to comprehensive route selection, integrated vibration and noise reduction, prefabrication and pre embedding. Its construction cost is significantly lower than that of the other metro lines constructed in the same period, improving the quality of engineering and realizing green construction of urban rail transit. Moreover, the application of distributed photovoltaic power generation, sponge city, cloud platform, regenerative braking energy absorption, combined switch cabinet of traction network and air quality improvement has greatly contributed to the reduction of energy consumption during operation and the achievement of low-carbon urban rail transit operation. The exploration and implementation of Shenzhen Metro Line 6 from design to construction and operation set a convincing illustration of achieving the “peak carbon dioxide emissions and carbon neutrality” goal, accelerating the green and low-carbon transformation of urban rail transit and mining the potential of energy conservation and emission reduction.
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Research on anti-skid performance of wet-slip straddle monorail pavement based on tire-road coupling

ZHAO Yang, LEI Zhenguo, CHEN Baikun

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In order to study the driving safety of straddle-type monorail vehicles under different working conditions, the operation status of straddle-type monorail vehicles in rainy, snowy and wet environments was studied. Based on CEL and finite element method, a coupled tire-road simulation model was constructed. On this basis, the changes of parameters such as wheel-rail vertical force and wheel-rail stress under different water depths and different driving speeds were studied. The relationship between water film thickness and wheel-rail vertical force and tire stress was explored. The research results show that the influence of anti-skid performance of pavement on the numerical change of tire contact parameters of monorail vehicles is the main inducement for driving safety. The vertical contact force of the vehicle tires decreases rapidly with the increase of the thickness of the accumulated water; when the road is covered with water, the tire stress will decrease with the increase of the depth of the accumulated water, thereby causing the wheel to drift and the occurrence of instant slippage. The research can provide a theoretical basis for the development of safety measures for straddle monorail.
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Analysis of the Impact of Accessory Structure Construction on the Prefabricated Station Metro Structure

LI yan chun, MAI qin xin, Liu si yang, LI Mengting

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In order to ensure the safety and stability of the main body of the prefabricated station during the construction of the accessory structure and to understand the mechanical law of the main body of the prefabricated station during the construction of the accessory structure, the internal forces and deformation of the main body of the prefabricated station during the construction of the accessory station were analyzed by finite element numerical calculations with the Shenzhen metro prefabricated station Line 13 City Hospital Station as the engineering background. The calculations show that: 1) the excavation of the subsidiary pit leads to the bias load effect of the main body of the station, and the overall structure has a tendency to deform to the side of the subsidiary excavation, and the internal force of the structure is redistributed, and the internal force and deformation of the vault is significant near the side of the subsidiary pit excavation.2) The internal force and deformation of the main body of the assembled station can be controlled by temporary support measures above the main body roof, measures of the main body vault buttress connection, and measures to strengthen the rigidity of the subsidiary support during the construction of the subsidiary, among which, the temporary support measures above the main body roof are effective. Combined with the calculation and analysis results of the design measures, the design application of the above control measures is studied in the context of the implementation of this project, so as to provide reference for the design of prefabricated subway stations.
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Analysis of the effects of geological parameters and different buried depths on the structural mechanical properties of single-arch large-span prefabricated stations

LIU renpu, MENG dong, ZHENG shuyue, WU chenggang

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With the construction of prefabricated stations in coastal cities, the influence of weak soil on the mechanical properties of station structures has become one of the most concerned issues. Therefore, this paper takes an prefabricated station in Shenzhen as the engineering background, uses Midas-GTS finite element analysis software, establishes the strata-structure model, analyzes the mechanical characteristics of the Single-arch large span prefabricated station, explores the effects of different elastic modulus, different Poisson's ratio, different geological conditions and different buried depths of the station on force and joint internal force of the underground station, and gives a theoretical basis and structural design guidance for the structural adaptation of the prefabricated station to the stratum. The results show that: 1)When the Poisson 's ratio is constant, the elastic modulus has a great influence on the mechanical properties of the station structure. When the elastic modulus increases from 15 MPa to 60 MPa, the bending moment decreases by 44.58 %, and the influence is nonlinear. When the elastic modulus is 15MPa-30MPa, the structural deformation is more sensitive. When the elastic modulus reaches more than 45MPa, the sensitivity of structural deformation decreases. 2) strata have a greater influence on the internal force of the top plate span middle and bearing, and the strongly weathered geological reduces the bending moment by about 40% compared with the fill layer, while it has a smaller influence on the internal force of the sidewall and a greater influence on the BC joint. 3) when the underground station is located in the fill layer, the internal force of the BC joint is smaller. When the soil layer is fill layer, the redundancy of BC joint moments is very small, and it is necessary to strengthen the design of joints or to improve the geological appropriately. 4) Under the hard plastic geological condition , when the station burial depth increased from 3 m to 5 m. the BC joint moment redundancy decreased by 35.37%. however,the joint redundancy all reached more than 29%, and the safety reserve of the joints was larger and the joints were reliable.
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Study on Seismic Response of Prefabricated Station Based on Beam-composite Spring Model

LI Xia

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Based on the existing research results of prefabricated station structure, a simplified dynamic analysis model of beam-composite spring suitable for prefabricated subway station structure is established and the validity of the model is verified through comparing the analysis results with 3D solid model. The comparative analysis of the transverse seismic response of prefabricated subway station structure and the same type cast-in-place structure is carried out by using the model. The results show that: Under the horizontal earthquake action, there is little difference in deformation between prefabricated station structure and the same type cast-in-place structure. The fluctuation trend of the internal force of the section of the prefabricated station structure is the same as that of the cast-in-place structure and both reach the peak at the same time. The bending moment and the fluctuation amplitude of the typical section of the prefabricated subway station structure are smaller than that of the same type cast-in-place structure. The grouted mortise joints reduce the amplitude of the bending moment and amplitude of moment fluctuation of the structure section, weaken the bending moment response of the structure under the earthquake action. The research can provide technical support for seismic calculation of prefabricated subway station structures and reference for the application of prefabricated assembly technology to underground structure construction.
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Analysis of Longitudinal Force on Prefabricated Station Structure Based on Shell - Spring Model

WU Chenggang, HUANG Meiqun, ZHENG Shuyue

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With the wide spread and application of prefabricated station, it is also facing more and more complex geological conditions. The problem of longitudinal force of prefabricated station structure is more prominent in the soft-hard uneven stratum. In this paper, a prefabricated station of Shenzhen metro was taken as the engineering background, and the shell-spring model was constructed by finite element numerical simulation method to investigate the longitudinal settlement and stress characteristics of the prefabricated station structure under the complex conditions of soft-hard uneven stratum. The results show that the longitudinal force of the structure in uniform stratum is mainly affected by the middle column, while its influence is slight. It is more obvious that the longitudinal uneven settlement of the prefabricated station structure in the soft-hard uneven stratum. Furthermore, the shear stiffness between structural rings has a great influence on the longitudinal uneven settlement of the station. The soft-hard uneven stratum not only affect the longitudinal force of the station structure, but also have a certain influence on the transverse force of the station structure. The bending moment of arch crown and shoulder at roof plate increases by about 10%, while the axial force of arch crown decreases by about 8%. The influence of these factors should be considered in the design. In the stratum of sudden change of the rock surface, the shear force of the bottom plate structure has a sudden change at the sudden change position, which is unfavorable to the stress of the ring seam of the structure, while the shear force change is relatively uniform in gradual stratum. At the same time, the longitudinal deformation of the structure exists in the soft-hard uneven stratum, which increases the opening amount of the ring seam. Therefore, the influence of this factor should be considered in the control of the width of the ring seam. In a conclusion, for soft-hard uneven stratum with large difference, certain reinforcement measures should be taken to improve the bearing capacity of the soft soil layer and reduce the longitudinal uneven settlement of the structure.
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Construction Cost Analysis of Prefabricated Subway Station

leiying

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Abstract: With the popularization and application of prefabricated subway station, its construction cost has become one of the key issues. Based on a domestic subway station project, an analysis model of the construction cost of the prefabricated station is established. The construction cost of the full cast-in-place rectangular section scheme, the partial prefabrication scheme with the rectangular section (prefabrication rate: 43%), the full prefabrication scheme with the rectangular section (prefabrication rate: 64%) and the full prefabrication scheme with the arch section (prefabrication rate: 60%) are analyzed. The cost difference of different construction schemes is compared. Besides, the cost control measures of the prefabricated station are proposed. Compared with the full cast-in-place scheme of rectangular section scheme, the estimated cost increase of different prefabricated station schemes is about 11% ~ 18%. The overall cost increase of the station is not large, and there is still room for optimization. The research results can promote the construction cost control of prefabricated metro stations and provide reference for the construction of related projects. Keywords: prefabricated subway station; prefabricated member; construction cost; cost control
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Research on the design scheme of medium plate beam column in prefabricated metro station

LI Mengting, WU Chenggang

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Based on the engineering background of the design and application of prefabricated station of the revising of Shenzhen rail transit in phase Ⅳ, this study investigates the design scheme of prefabricated medium plate, beam and column of prefabricated metro station on the basis of the prefabricated station scheme of open-cut inner support system. This paper focuses on the flow assembly step sequence of station with prefabricated and composite medium plate, and the stress and deformation of the enclosure and the medium plate in the flow assembly step sequence have been analyzed and calculated. Through the analysis of the stress of the medium plate in the construction stage and the application stage, the prefabricated components and composite components were designed. In addition, the steel support was set in the middle plate to meet the requirements of station assembly and foundation pit stress conversion, which solved the design difficulty of opening large holes in the medium plate. After the station assembly is completed, the cast-in-situ longitudinally transverse beams and laminated layers are cast at the hole edge to form the hole edge reinforcement structure. Finally, the steel support in the hole is removed and a permanent opening is formed. At the same time, the shear connections were set at the opening position of the medium plate, so that the prefabricated plate, the composite layer and the longitudinally transverse beams form an integral structure and bear the horizontal force in the medium plate plane together. It is used the inner arch effect of the integral structure to avoid the stress concentration in the longitudinally transverse plane of the hole. Through the above research on the prefabricated medium plate, the full section assembly of the metro station is realized, and further promote the assembly rate of the metro station and the efficiency of the flow assembly of the station, which provides a reference for the design of prefabricated metro station.
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Structural calculation and optimization design of prefabricated underground station in the backfilling stage of foundation trench

PENG Zhiyong, YANG Xiuren, HUANG Meiqun

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The backfilling of foundation trench is a common construction stage in the construction of open excavation prefabricated underground station. If the structure calculation is carried out in the traditional way, the calculation details at this stage are easy to be ignored. Considering the dynamic change of internal force and deformation of prefabricated underground structure with the construction process, it is necessary to clarify the important role of backfilling of foundation trench in the calculation of open-excavation prefabricated underground structure. In this paper, firstly, the mechanism of the influence of concrete liquid state to solid state on structure during the backfilling stage of foundation trench is analyzed. A structural calculation model based on the inheritance effect of liquid backfill load is proposed. The increment method is used to analyze the mechanical change law of prefabricated underground structure with or without inheritance effect. On this basis, the structure optimization analysis of the prefabricated underground station is carried out from the perspectives of the number of backfilling times of foundation trench, the adjustment of operation procedure and the adjustment of structure form. For the prefabricated underground station structure, the results show that: (1) the liquid inheritance effect of foundation trench backfilling mainly affects the structural design of the side wall; (2) The number of layered backfilling mainly affects the stability of prefabricated underground structure in the backfilling stage of foundation trench. The less the number of layered backfilling, the more serious the vault uplift and arch foot retraction of arch prefabricated underground structure. (3) Reasonable application of process adjustment (such as the middle plate installation before the backfilling of the trough) can significantly improve the inhibition of the uplift of the arch and the shrinkage of the arch foot, but the process adjustment can cause the increase of the internal force of the side wall area, and the influence of the internal force and deformation of the structure is opposite. (4) When the structure of arch prefabricated underground station is adjusted to a rectangular structure, the risk of instability in the backfilling stage of the structure foundation trench will be significantly reduced, and the internal force of the structure will be reduced, and the influence on the internal force and deformation of the structure will converge.
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Mechanical influence of empty support on prefabricated arch structure

pengzhiyong

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In the actual assembling process of the prefabricated double - member arch structure, the phenomenon of jack empty support is easy to be caused by the asynchronism of the stroke. Based on the three-dimensional numerical calculation, the paper analyzes the different empty of the fabricated under the condition of double component top arch structure, mechanical properties, and on the basis of maximum principal stress failure criterion, completed the different empty mechanical properties of the fabricated under roof arch structure, evaluation, research and analysis found that: (1) the upper supporting platform for empty when, structure of inner development trend of maximum principal stress to compressive stress; (2) When the lower supporting platform is in empty support, the maximum principal stress in the structure develops towards tensile stress; (3) When only the upper supporting platform is in empty support, the main body of the prefabricated double-member top arch structure meets the maximum principal stress tensile design limit; (4) When there is any empty support of the lower supporting platform, the partial area of the prefabricated double-member top arch structure will not meet the maximum principal stress tensile design limit. Compared with the original state, the tensile amplitude of the structure increases by 567% to 841%.
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Research of Virtual Coupling Technology based on Vehicle-to-Vehicle Communication

陈凯

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Virtual coupling technology, an effective means to improve the efficiency of rail transportation capacity use, can solve the problems of operation cumbersome and train network low initial efficiency existing in mechanical coupling. To improve the flexibility of operation and achieve safe and efficient train tracking, this paper summarizes the ideas of transparent transmission and closed-loop control of mechanical coupling. And on the basis of the safety interval protection technology of the preceding train speed and the dynamic operation adjustment mode of threshold management, a virtual coupling scheme based on vehicle-to-vehicle communication and vehicle-signal system fusion is proposed. Based on high-quality vehicle-to-vehicle communication technology, real-time communication occurs between two vehicles, and the following train fully responds to the control command and operation status of the predecessor and always operates based on the safety status of the predecessor. In this case, the closed-loop synchronous control of the virtual coupled train can be realized and further reduce the internal running interval of the virtual coupled train, improving the operation efficiency of the train. The proposed scheme provides a reference for the practical application of virtual coupling synchronous control.
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Research and Application of the Key Technology of Joint Waterproof for Prefabricated Metro Station Structures

LIN Fang

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The joint waterproof performance of the prefabricated metro station structures has been paid much attention by the industry. In view of the characteristics of the structure, component manufacturing and construction technology of the prefabricated stations, this paper analyzes the main influence factors and control indexes of the two key parameters of "joint gap amount" and "gasket offset amount" which are highly related to the joint waterproof performance. Combined with the experimental research on the waterproof performance of the sealing gasket and the monitoring results of the actual engineering application, the key technologies of the multiple waterproof lines of “two gaskets + one injection + one embedding” of the joint’s seam have been fully demonstrated. The “two gaskets” use ethylene-propylene terpolymer (EPDM) elastic sealing gasket as the main waterproof, and the composite water swelling rubber as the reinforced waterproof, forming a composite porous sealing gasket with multi grooves. The sealing gasket is the main defense line of the joint waterproof line, and the grouting and caulking are the auxiliary defense lines. The research and practical application show that the joint waterproof of prefabricated station structures is different from that of shield tunnels not only in waterproof structural measures, but also in various control standards. The gap amount of 10mm and the offset amount of 5mm are reasonable indicators for the joint waterproof performance control for prefabricated station structures. The single waterproof sealing gasket can resist the water pressure of 1.0MPa under the condition of the gap amount as 10mm and the offset amount as 5mm, meeting the performance requirements of the station structure with 30m buried depth to resist 2-3 times of the head pressure. After 100 years of use, it still has about 67% residual stress value, and has long-term water pressure resistance performance. The double sealing gaskets have limited improvement in waterproof performance compared with the single sealing gasket, with an improvement rate of 20% ~ 30%. However, when there is local water leakage in the outer sealing gasket of the lining, the double sealing gaskets have significant advantages. From the perspective of reasonable tensile load of joints, the hardness of EPDM rubber gasket needs to be reduced by 5SHA compared with that of conventional shield tunnel, i.e., 60SHA is adopted, and the complete compression load index per unit length is not more than 40kN/m. According to the existing and under construction projects, the measured maximum gap of the joint for the station structure and the maximum offset of the surface meet the requirements of the joint waterproof performance control standard. In the case of no external waterproof layer, there is no leakage at the joint.
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Research on the Influencing Factors and control of Longitudinal Tensioning Force of Prefabricated Metro Station

wuchenggang, 杨秀仁

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Prefabricated metro station has been widely used in Changchun, Qingdao, Shenzhen and other cities. The joint width is an important factor in determining the assembly quality of prefabricated station. A case study of Shenzhen metro prefabricated station is undertaken to further improve the assembly quality of prefabricated station and better control the joint width of prefabricated stations. This paper emphatically analyzes the influencing factors and control methods of longitudinal tensioning force of prefabricated station. The result of the analysis shows that the main factors affecting the longitudinal tensioning force of prefabricated station are the layout of tension points, the stiffness of elastic gasket, the friction between components and contact object, and the construction attitude of components in the stretching process. Among them, the stiffness of rubber gasket is the main influencing factor of longitudinal tensioning force, so different control values of tensioning force should be adopted according to the stiffness of sealing gasket to achieve the control width of joints. In addition, the longitudinal tension point has a great effect on the compression uniformity of rubber gasket. Thus, the compression of rubber gasket can be effectively controlled within 1mm when the longitudinal tension point spacing of long and large components is about 5m. What’s more, the side wall components and the arch vault components are tensioned when the sling is not completely unloaded, which can effectively reduce the influence of the component translation on the contact waterproof gasket, and is conducive to the tension of the components in place. Through the monitoring of the longitudinal tensioning force at the construction site, it is found that the tensioning force of each ring is not constant which is mostly distributed in 295-310 kN and the tensile force of the side wall and roof components is slightly larger than that of the floor components.
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The Practice and Thoughts on the Pass-through Operation Implementation Plan Between Urban Metro and Suburban Metro ——Case of Bejing Metro Line 1 and Batong Line

XU Chengyong, LI Tianshi, ZHANG Xiaowei

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Batong Line is situated in the eastern part of Beijing. Passengers have expected pass-though operation between Beijing Metro Line 1 and Batong Line for a long time as a result of strong centripetal travel demand, and more than 80 percent of passengers transfer at Sihui Station and Sihuidong Station for working in central city. With the review of Line 1 and Batong Line construction, the paper sorts out the planning conditions for the pass-through operation, and summarizes the experience of overseas urban rail transit lines connected with suburban lines. Based on the Tokyo urban rail transit case, the shortcomings of the Batong Line at the early planning and design stage are analyzed and the needs for pass-through service renovation is discussed. A scheme with four turnouts was determined through alternative comparison. The renovation plan for the pass-through service considers both through and separate operating modes, which can not only provide a more refined passenger transportation management, but also play a role in Saving & Efficiency. On this basis, the technical standards for the pass-through renovation are integrated and the principle of design specifications not lower than the construction phase of the existing line is proposed. Finally, in order to maintain the regular operation of the line and depot during construction, a three-stage proposal was adopted for gradual through service and a favorable renovation effect was achieved. The renovation of Line 1, China's first subway line, has successfully optimized the connection between Line 1 and Batong Line, creating a new milestone in the history of urban rail transit development in China.
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The Reflections on the Interaction Between Nanjing Rail Transit and the Urban Space Development

CAI Yuping, HUANG Juan, CHANG Bingyang, Xu Yakun

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This paper studies the interaction between Nanjing rail transit and the urban development from the aspects of planning and implementation effect. Firstly, by combing the interactive relationships between the rail transit network plans and the urban master plans of Nanjing, this paper expounds the demand of the urban space development strategy for rail transit network layout in various periods and different urban development status, and shows the attributes of "according to and supporting the master plan" of the Nanjing rail transit; Then, by analyzing the impact of the urban rail transit on the urban space development, this paper verifies the reaction of the rail transit on the urban development, and shows the role of rail transit in "surpassing and returning to the master plan". The development of Nanjing Metro has played an important role in leading the expansion of urban space, supporting the construction of the polycentric system, promoting the three-dimensional and intensive construction of the city, and guiding the distribution of urban population and industry. Through the consideration of the problems in the interaction between rail transit and urban spatial development, the author puts forward some development strategies of rail transit for the next stage, such as rationally responding to the needs of regional development, strengthening the coordinated construction of rail transit and urban space, and scientifically leading the integrated development of metropolitan areas.
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Study on Stress Characteristics of Prefabricated Subway Station Foundation Pit Support Structure Under Internal Support System

XU Haihui, WU Chenggang, ZHANG Yuanrong

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Taking the prefabricated subway station of Shenzhen Hospital of traditional Chinese medicine as the engineering background, combined with the engineering geological conditions of the station and the construction process of the prefabricated station, the ground structure model is established by using ABAQUS finite element analysis software.The deformation law of the foundation pit, the change law of the axial force of the support and the stress characteristics of the inverted continuous support during the construction of the prefabricated station are emphatically analyzed. First, the deformation of the foundation pit of the prefabricated station is mainly divided into the excavation stage and the station assembly stage. The total deformation of the diaphragm wall is 10.31mm, of which the excavation stage is relatively large, accounting for 88.6% of the total deformation. The deformation trend of the foundation pit during the excavation process is the same as that of the cast-in-place station; In the process of support replacement and structure assembly, the deformation of the diaphragm wall accounts for 11.4% of the total deformation, and the variation range is 0.05 ~ 0.99mm. The deformation value and range are quite different from those of the cast-in-situ station; Support removal and support replacement are important construction steps in the construction of prefabricated stations. The temporary support axial force of the middle plate near the support removal ring is large, accounting for 80% of the total support replacement axial force. Therefore, when arranging connecting supports, the number of connecting supports near the support replacement ring can be appropriately increased, and the number of connecting supports far away from the support replacement ring can be reduced; The results of numerical calculation and field monitoring are compared, and the change laws of the two are basically the same, which verifies the effectiveness of the numerical analysis.
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Research and Formulation of Control Standard for Assembly Accuracy of Open-Excavated Prefabricated Tunnel Structures

Yang Xiuren

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The research and application of construction technology for open-excavated prefabricated tunnel structures is still in its infancy in China. The control standard of assembly accuracy is an important ruler to measure and control the project quality during the construction of prefabricated structures. The reasonable formulation of the standard is related to the safety, reliability, economic rationality and practical operability of the project construction. Through the analysis of the factors affecting assembly accuracy, the theoretical index has been proposed, and combined with the practical application of the project and the analysis and refinement of the normal distribution curve of the measured values, the control standards for the main control elements of the assembly accuracy for the open-excavated prefabricated tunnel structures have been developed, including the axis plane positioning deviation, elevation positioning deviation, component shape and attitude deviation, joint opening, structural surface dislocation, longitudinal dislocation of the same ring. The allowable values such as the plane dislocation of the front and rear circumferential longitudinal joints have been compared with the relevant standards for open-excavated cast-in-place tunnels, shield tunnels and prefabricated integral structures. The research and actual engineering application proves that the control standards are generally reasonable, which can be used as a reference for subsequent engineering construction and the formulation of relevant standards. The component fabrication accuracy has a great impact on the assembly accuracy. Improving the component fabrication accuracy is of great significance to improve the assembly accuracy. The self-weight compaction mode is the most favorable for controlling longitudinal joint opening of the tunnels. The opening amount of circumferential joint for the tunnels can be effectively controlled by controlling the tensioning load, improving the accuracy of component fabrication, controlling the cumulative error of construction, etc. The positioning pin bar is set at the joint, and the positioning accuracy and the amount of space reserved are strictly controlled, which plays a key role in the control structure indicating the amount of platform staggering.
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Assembly design method and key technology of open-excavated prefabricated tunnel structure

Yang Xiuren

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The assembly technology of prefabricated tunnel structure under open-excavated construction is quite different from shield tunnel. In the engineering design stage, the structural assembly needs to be planned and designed in detail according to the structural type and assembly mode, so as to support high-quality and efficient construction, ensure the bearing performance and stability of the structure, and meet the waterproof performance requirements of joints. Based on the research and practical achievements of the author and his team in the construction technology of open-excavated prefabricated metro stations over the years, this paper systematically summarizes and discusses the assembly design method and key technologies, and puts forward the assembly method, base surface fine leveling technology, positioning control technology, tension locking technology, roof support limit measures, precision control standards and other assembly key technologies. In general, the open-excavated prefabricated tunnel structure shall take the fixed end of the first ring as the starting point, proceed along the longitudinal direction, and follow the basic principle of "from bottom to top", and assembly block by block and layer by layer. The base surface at the bottom of the foundation pit shall be finely leveled, and according to the foundation conditions and the structural type of the bottom plate, fine leveling strip method or foundation surface leveling method can be selected. The tunnel lining structure should be equipped with a certain number of guiding and positioning devices at the joint assembling surface to effectively control the dislocation of the structure surface while helping to accurately locate the components. The open-excavated prefabricated tunnel should be set on a straight line as far as possible. When the tunnel is located in a curved section, the curve can be fitted by means of "wedge-shaped component + equal width joint" or "equal width component + wedge-shaped joint". However, the maximum joint width of the wedge-shaped joint should meet the requirements of joint waterproof performance, and it is difficult to control the assembly accuracy, so the construction is challenging. The tensioning and locking of longitudinal and circumferential assembly should adopt the tensioning and locking method of prestressed steel bar or bolt. The "centroid tracking method" should be used for prestressed tensioning, and the multi-point coordination and synchronous tensioning and locking should be used to maintain the uniformity of the joint width, effectively control the opening of the target joint width, and timely fill the gap under the prefabricated bottom plate with grouting, and timely support and limit the side wall, arch foot and other key parts.
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Influence Study on Key Structural Parameters of Grouted Single-Tenon Joint

LIN Fang, YANG Xiuren

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Different geometry structures of grouted mortise-tenon joint for the prefabricated metro station structure have different impacts on the mechanical properties of joint, thus affecting mechanical behavior of the whole structure. Based on comprehensive performance experiments, analytical and numerical research findings, this paper conducts research on structural design of the joints from five indexes of the joint: tenon proportion, thickness-width ratio of joint, dip angle of the tenon, length-width ratio of joint and indentation rate, which contains key construction parameters: length and width of the tenon, height and width of the joint, thickness of mortise top and bottom, length of indentation. Finally, specific range of geometry structures and design requirement of the joint are developed with consideration of bending and shear capacity of the joint of every index, convenience of manufacturing and accuracy of positioning. Which provides guidance for similar connection of prefabricated elements.
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Study on the effect of auxiliary tension device on the mechanical properties of grouted mortise-tenon joint

LIN Fang

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In order to study the mechanical characteristics of auxiliary tension device for the grouted mortise-tenon joint, this paper first introduces the structure of the joint with auxiliary tension device in detail. Based on the joint test results, the characteristics of the pretightening steel bar in different stress property areas have also been analyzed, and it is clear that the function of the auxiliary tension device is to delay the damage and increase the ductility of the joint. At the same time, taking Changchun prefabricated metro station structure as an example, the practical effects of the auxiliary tension device of various types of the used joints have been analyzed. Next, based on the algorithm of grouted mortise-tenon joint, the influences of the settings of different auxiliary tension devices on the bearing capacity of the joint have been analyzed from the two aspects of the preloads and the positions of the pretightening steel bar. The results show that: it is recommended to set the pretightening steel bar on the tension side, and when the axial force is small, appropriately increasing the preload value of the pretightening steel bar can improve the later bearing capacity of the joint; Larger preload has obvious effect on the nonlinear bearing stage of the joint, but has little effect on the linear bearing stage; For the joint with auxiliary tension device on the tension side, when the preload is large enough, setting the pretightening steel bar at a certain distance from the central axis within the allowable range of the joint’s structure will increase the elevating effect of the pretightening steel bar on the later bearing stage of the joint; For the joint with auxiliary tension device on the compression side, avoiding large preload of the pretightening steel bar and setting it closer to the central axis are recommended.
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Performance Analysis of Grouted Single-Tenon Joint Based on In-suit Monitoring

LIN Fang, YANG Xiuren

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The whole-process monitoring and measurement of prefabricated mero station structure is carried out for the first time in Changchun Metro Line 2. Based on the whole process monitoring data of on-site construction and operation, this paper analyzes the internal force and deformation of the grouted single-tenon joint at the arch foot. The performance of grouted single-tenon joint in different stages has been grasped, and the numerical results have also been compared. The results show that: after the components are assembled into a ring, the mortise and tenon of the joint embedded into each other, and the tenon shows bending effect. After the backfill, the joint mainly resists moment effect. The overlying soil backfill and water-level recovery play a positive role in the deformation and stress of the joint. The monitoring results are relatively stable from the end of construction disturbance to operation. The overall internal force and deformation of the grouted single-tenon joint is small, and the safety margin is rich.
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Integrated Design of Auxiliary Structure Exits Between Utility Tunnel and Metro Station

LIU Wenbo, WANG Hongyi

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Associated with intensive utilization of underground space and improvement on ground landscape molded of urban development, in the process of promoting synchronous construction of utility tunnel and metro, it is necessary to achieve the integrated design of auxiliary structure exits between utility tunnel and metro station. The integrated design can avoid contradictions and mutual interference in the utilization of underground space, which is beneficial to optimize the urban landscape, enhancing the utilization availability of urban underground space, promoting the intensive, efficient and transiformation development of the city, and improving the comprehensive carrying capacity of the city and the quality of urbanization development. This paper analyzed the classification of utility tunnel node and the accessories of the subway station, combined the utility tunnel node and the accessories of the subway station. According to the classification of functions of each entrances combined with specifications and relevant design principles. 48 types of surface opening combinations were preliminarily obtained after analyzing the surface opening function. Based on the overall consideration of combination mode influenced on ventilation and exits and entrances, we finally proposed 14 integration thinking of 4 categories. The advantages of integration were quantitatively analyzed combined with specific cases. The research findings may provide some consult and reference for the following analogous engineering design.
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Technology Study and Application of Assembled Hollow Concrete-filled Steel Tubular Struts

OuYangDong

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In view of the “Double Carbon” strategic background, a new type of assembled hollow concrete-filled steel tubular strut has been proposed. In order to investigate the load-carrying behavior of the strut and to facilitate the introduction into the deep foundation pit of underground stations, two full-scale hollow concrete-filled steel tubular struts were designed and manufactured, and were further tested to failure under axial compression. The two strut specimens experienced the concrete crushing failure, and the load-carrying capacities of the tested specimens were obtained. Elaborate finite element (FE) models of the hollow concrete-filled steel tubular struts were developed by using the ABAQUS software package. Numerical analysis taking into account both material and geometric nonlinearities was conducted, and the obtained numerical results were in good agreement with the obtained test data, verifying the accuracy of the developed FE models. It has been demonstrated by the obtained experimental and numerical results that the newly proposed hollow concrete-filled steel tubular struts could satisfy the design requirement of ordinary engineering applications, and have been successfully applied in the No. 2 ventilation shaft project of Tangma Interval. This new type of strut was also compared with the cast-in-stie reinforced concrete strut and the steel tubular strut, and it was indicated that the introduction of the new strut could lead to significantly reduced carbon emission and decreased economic cost.
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Design And Research On Curve Radius And Superelevation Of Unconventional Subway Platform

Huang Dinggui, Wang Rui

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In order to solve the problem of the minimum radius of transition curve and the superelevation in RuYiFang station of Guangzhou Metro Line 11 exceed the provisions of 《Code for design of metro》,The controlling factors of the minimum curve radius, the superelevation and the length of the transition curve into the platform are summarized and analyzed.We checked and verified the Maximum clearance between platform edge and door threshold、the Maximum clearance between Platform Screen Door and train door、the length of the transition curve、the unbalanced centrifugal acceleration、the Maximum transverse acceleration、the inclination of trains within the platform range、the height difference between train floor and platform surface，The results show that it is the curvature radius of the transition curve is less than normative minimum value and practicable to set the superelevation higher than 15mm in RuYiFang station,and it is useful to save the investment and shorten the construction period. and that it offered a new method can be taken for reference by similar projects.
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Analysis of influence on deformation of adjacent subway tunnel due to bilateral deep excavations in soft soil area

CAI Zongyang, Zhang Ge, Pan Hao

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Based on double-side excavation along subway tunnels in soft soil regions in Hangzhou, the analysis of double-side excavation influence patterns on subways in operation is done by three-dimensional simulation and on-site data measurement. The results show that with the same excation depth, the dimentional difference of foundations is one of the important factors to horizontal displacement; The increase of deformation in removal of support and backfill should not be ignored, and the ratio from them is over 25% of total deformation; The constructions of support sturctures and pile foundations have obvious influences on subway; The deformation control techiniques applied in this project guarantees safety of subways near construction, and provide references for similar projects.
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Key Points and Practices of Mountain Cluster City Urban Rail Transit Network Planning——Taking Guiyang as an example

zhulan

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Since mountain cluster cities are restricted by natural conditions such as mountains, hills, and valleys, their urban forms, road network structure and traffic characteristics are different from those of plain cities, which will directly affect the layout of the rail transit network. In this study, by taking Guiyang rail transit network planning as an example, according to the characteristics of mountainous cluster cities, we optimized a method commonly used in transit network planning, analytic hierarchy process, involving elements of surface, point, and line. Furthermore, we analyzed and summarized the key points in the transit network planning stage of mountain cluster cities to provide references for the subsequent mountainous urban rail transit planning. Through research and analysis, the key point of planning in urban rail transit networks for mountain cluster cities is proposed. In the analysis of the "surface" element, the key points include the quantitative analysis of the rail supply-demand relationship in key transport sections, as well as the proposal of the rail supply scheme according to the combination of the demand and the network form. In the analysis of the "line" element, the vertical relationship should be paid full attention to and used in transit network planning to increase the accessibility of rail transit; In the analysis of the "points" element, topographic factors should be fully considered in the layout of stations and the surrounding land should be well connected.
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Development conception of intelligent early warning device for vibration and noise monitoring of urban rail transit operation line

Maxiaohua

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Vibration and noise problems need to be transformed to the mode of "active prevention and control of early warning". It is urgent to develop an intelligent early warning device for vibration and noise monitoring. This device can monitor the sensitive points in real time and master the deterioration of the line over time. The device consists of three modules: vibration and noise status monitoring module, vibration and noise warning module, and early warning data information sharing module. Vibration and noise status monitoring module completes the collection of current data, and transmits it to the server in real time, and stores each real-time step. Then, through the vibration and noise warning module, the state of vibration and noise can be assessed by comparing the test data with the report of similar project time-consuming data, and the adjacent points with vibration and noise exceeding the standard can be compared and analyzed by historical data and simulation, so as to give an early warning to the threshold of the near-set grading. After the start of early warning, maintenance departments should take corresponding remediation measures to suggest, collect relevant data of anomaly monitoring system and on-site survey. Finally, the transformation from "passive remediation of complaints" to "active prevention and control of early warning" mode will be achieved.
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Analysis of problems in the Application Public Offering REITs in the Field of Urban Rail Transit

Dong Shuyun

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Combined with the characteristics of public REITs and development status of urban rail transit, the applicability and existing problems of REITs in the field of urban rail transit are analyzed, and the preconditions for urban rail transit to carry out REITs pilots are proposed. Because urban rail transit is a large-scale infrastructure and a quasi-public product, it generally implements government pricing and lower fares are the norm. Lower fares and higher construction and operating costs make it difficult for ticketing revenue to cover operating costs. According to statistics, the national average operating revenue and expenditure ratio in recent years is 65% - 78%. Therefore, at this stage urban rail transit does not meet the preconditions that the underlying assets of REITs can make their own profits, and is not suitable to be the underlying assets of REITs. If REITs are issued through asset restructuring, whether taking the network or operation as the underlying asset, it will bring about problems such as increased financial subsidies and increased government debt. Therefore, at this stage, there are no conditions for the widespread promotion of REITs in China. Some high-quality projects in developed cities can be selected for pilots. It is suggested to judge whether the project is a high-quality project through its own profitability and government financial resources. For pilot projects, we should also pay attention to the reinvestment project, the level of asset managers, rents, commissioned operation and management fees and other charging standards.
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Discussion on Application and Maintenance of Ballast Track in Urban Rail Transit

chenpeng, xiejiale, jingguoqing

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Developing green, low-carbon and sustainable urban rail transportation is of great significance to accomplish the goal of "carbon peaking and carbon neutrality". In this paper, the application and maintenance of ballast track technology in urban rail lines are discussed, and research ideas are provided for the high-efficiency and high-quality development of urban rail transportation. On the basis of summarizing the service-life of conventional ballast bed, the service-life of ballast bed in various forms of urban rail lines are estimated through the annual line throughput, and further structural selection researches are carried out for the ballast bed of ground line and elevated line in urban rail transit. On this basis, the novel machinery and maintenance technology for the maintenance and maintenance of ballast bed at home and abroad are introduced to offer reference for the actual engineering application of ballast track in urban rail transit.
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Deepening research on the development of smart straddle monorail

Wei Hongwei, Tian Wo, Lei Huifeng, Lin Yao, Hu Guohua, Sun Xiaotong

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At present, more than 30 cities have carried out planning and research on the straddle type monorail as an urban transportation trunk line, but none of them have had an in-depth study on the intelligent construction of straddle type monorail, so there is still a lack of relevant guidance documents for the intelligent construction of straddle type monorail. In order to fill this gap, based on the technical and application characteristics of straddle type monorail, and under the guidance of the Development Outline of Smart Urban Rail Transit in China ,we systematically studied the construction scheme of smart straddle type monorail, including the adaptability of intelligent urban rail technology in the field of straddle type monorail, the unique intelligent key technology of straddle type monorail in operation control, design and construction, operation and maintenance management, low-carbon environmental protection and light weighting . Finally, the paper proposed a unique architecture for the intelligent straddle type monorail, and preliminarily planned the standard system and construction route of intelligent straddle type monorail.
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Zeng Yu, Fang Sun, Liang Liang, Hao Wu, Kan Zhang, Guangkun Zeng, Zhuqing Zhou, Ruidong Wei, Baoman Xue

yuzeng, sunfang, liangliang, wuhao, zhangkan, zengguangkun, zhouzhuqing, weiruidong, xuebaoman

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this paper studies and implements the real-time monitoring of each equipment system through the active global perception of multi-objects. Conduct risk assessment and hierarchical early warning for the faults of key driving equipment, provide optimized disposal suggestions for dispatching and command, realize the information control of the whole life cycle of equipment, and provide accurate intelligent operation and maintenance services for operating enterprises. By the research of road network level data sharing platform, the standard system and standard norms, the centralized monitoring platform system demonstration application，clear multiple equipment control platform of key technology, system architecture, functional requirements, according to professional centralized monitoring, control network equipment information, realize professional multiple line comprehensive operations, maintenance process controllable, for the subsequent intelligent operational analysis decision system, urban rail operation equipment big data monitoring safety evaluation system, intelligent inspection system, based on BIM integrated operational supervision system construction to provide technical support, provide the rail transit industry intelligent operational security system construction ideas and guidance, steadily improve the intelligent operations and safe operation level.
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Research and application of key technologies for autonomous and controllable urban rail cloud and big data platform

xushangnong, zhangminbo, lvyu, wangming, liujun, fanwei

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With the evolution of cloud computing, big data, Internet of things and artificial intelligence technology, the single line operation of urban rail transit has changed to a networked operation mode. Under the new business mode, the construction of urban rail transit cloud platform and big data platform, the implementation of Internet strategy, and the promotion of informatization and intellectualization can effectively realize the standardization of business management, improve the efficiency of operation, production and management, improve the level of operation services, and reduce operating costs. Guided by the smart urban rail development outline of the Urban Rail Association, in view of the pain points existing in the current construction and operation practice of urban rail cloud and big data, such as independent and controllable facilities, data fusion and sharing, safe and efficient operation, we carried out in-depth research on the key technologies of urban rail cloud and big data cloud security system, operation and maintenance management system, and formed research results on the key technologies of urban rail cloud and big data platform for independent and controllable, It provides reference and reference for promoting the transformation and upgrading of urban rail transit digitalization, intelligence and intelligence.
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Research on Application of New Energy Technology in Urban Rail Transit System

Cui Tingrui, Li Li, Li Ming

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In order to support the sustainable development for green and environmental protection of rail transit system, this paper is started from the perspective of system design, studied from photovoltaic power generation, hydrogen fuel cell and hybrid energy storage, and provides strong support for the improvement of overall energy efficiency of urban rail transit system from the perspective of new energy technology. Distributed photovoltaic - energy storage power supply system for urban rail transit system is researched. Multi - system, high reliability power supply mode and coordinated control strategy is developed. The energy management strategy under the coupling of source storage and multi energy is studied. For photovoltaic energy storage connected to a single traction substation, an energy management and optimization method based on deep reinforcement learning is proposed. This method uses deep Q-network to train and learn the state information such as train load, power output of photovoltaic unit and energy storage unit, and manages the energy of DC traction network through trained agents. The photovoltaic power generation system is difficult to adapt to the frequent start and stop of urban rail trains, the changeable working conditions, and the problems of power supply stability, capacity configuration and energy management caused by the introduction of multi-energy system, so as to effectively improve the green energy utilization rate of urban rail transit system and reduce the output energy consumption of substation.
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research on global scheduling system based on interconnection

le mei, wen cheng xiang

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Under the circumstances of large-scale operation networks, it is becoming increasingly prominent to break the disadvantages of the traditional single-line dispatch and command mode of urban rail transit, such as cumbersome dispatching process, poor linkage and communication between lines, and low efficiency in handling emergencies, and to improve the dispatching management and control capabilities at the network level. In this study, a multi-source big data platform for urban rail transit is built by means of the key technologies of urban rail transit multi-source big data analysis, the core functions of the global dispatch system is realized by means of the key technologies such as intelligent preparation of operation plans, intelligent dispatch of global train operations, and global emergency coordination and command, and a new generation of intelligent interconnected global dispatch system is developed and deployed, with the major demand for urban rail transit for the rapid development of big cities as the traction, the existing research and practice achievements of Chongqing Railway Group as the basis. It is proved that the system can significantly enhance the efficiency of interconnection, improve operation efficiency from the system level, save operation costs, and provide reference and guidance for the construction of interconnection global dispatching system.
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Research of two-level architecture network dispatching system for Multi-line of the city rail fast line

ZHANGZHENGBIN, 孙柯, LIULING

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In order to meet the needs of network operation and public transportation operation of urban rail transit lines, a network dispatching system suitable for multi-line traffic dispatch management of urban rail express line is studied. Based on the actual situation of Chongqing urban rail Express project, analyzes the network operation requirements and operation management and control mode, and puts forward the operation management and control mode of "two-level structure and comprehensive management". From the system function, system architecture, system interface aspects of network dispatching system solution is studied and comparison, expounds the unified management was carried out on the line network operation based on a train diagrams of network scheduling related functions, integration is proposed based on center - station, the center server distributed set of network scheduling system overall architecture, And the proposed implementation scheme of interface standardization between network dispatching system and interlocking and ATC subsystem.
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Design of Interconnection ZC Safety Communication Computer Platform based on ARINC659 Bus

weidongdong, 郑长宗, 许镇

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In order to better meet the demands of urban rail transit interconnection on safety communication in signal field, ARINC659 bus, which has advantages including large data throughput, definite transmission time, strict fault isolation and high fault tolerance, is used in the field of urban rail transit signal control system. This paper presents a scheme of 2oo2×2 safety communication computer platform based on ARINC659 bus technology to realize the external communication function and safety communication protocol operation function of ZC platform. By designing its software and hardware structure, the communication sequence of user software and threads between buses, as well as the research of key functions including data redundancy processing and safety protocol operation, the system can meet the requirements of high safety, high reliability and high real-time communication.
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The Design and Application of Urban Rail Transit Lighting Based on DC Power Distribution and Control

Li Jiaxu, XiangDong, Que Fan, Wen Zhenxing, Yang Shuncai

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Abstract:

The main line of Suzhou rail transit line 5 adopts an intelligent lighting system based on DC power distribution and control, and DC supplies power for LED lamps. The background reason and application scheme of selecting DC power supply are described. The high-frequency switch controllable rectifier power supply module is used as the DC power supply, and the IT grounding system is selected for the system. According to the output characteristics of the rectifier power module, a dimming protocol based on Manchester coding rules is developed. The command is transmitted through DC low-frequency carrier communication to control the lamps. A short-circuit fault protection method for distribution system with small capacity rectifier power module is proposed. By analyzing the influence of DC on the space charge of cable insulation, it is determined that the conventional AC cable products for low-voltage DC distribution can meet the requirements of cable insulation safety. A small capacity distributed photovoltaic power generation system is set on the roof of Yangcheng Hunan Station , which is connected to the DC lighting microgrid of the station to realize the application of multi port renewable energy access system. Suzhou line 5 was put into operation in June, 2021. At present, the DC lighting system operates smoothly.
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Research on Network- line-fused Dispatching Command System Based on Cloud Platform and Data Sharing Mode

Liu MinJie, Liang XiaoBin

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At present, the three-level (network-line-station) dispatching command system is widely used in domestic urban rail transit. Combined with the dispatching and command requirements of mid-sized cities urban rail transit network, this paper studies the construction scheme of Network- line-fused dispatching command system based on cloud platform and data sharing mode, and further analyzes the dispatching process, data sharing scheme and existing problems under the two-level architecture. Combined with the dispatching and command requirements of mid-sized cities urban rail transit network, this paper studies the construction scheme of Network- line-fused dispatching command system based on cloud platform and data sharing mode, and further analyzes the dispatching process, data sharing scheme and existing problems under the two-level architecture.This paper integrates the new generation of information technology achievements with the specific needs of urban rail transit, optimizes the dispatching command architecture, breaks the professional barriers of integrated supervisory control system, communication system and signal system, constructs a unified big data platform, and creates an open network dispatching command system based on cloud platform.
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Risk Assessment of Tram Operation Based on Fuzzy Comprehensive Evaluation Method

zhangqirui

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In order to realize the comprehensive identification and assessment of tram operation risk based on incomplete risk event data, an operation risk assessment method combining historical risk event data with expert experience was proposed. Firstly, the possible risk factors in the operation of tram were identified, and the three-level risk assessment system of tram operation was established by Analytic Hierarchy Process. Secondly, in view of the problem that the collected operational risk data did not cover all risk sources, the risk matrix method was used to evaluate risk sources that supported by data , and the expert scoring method was used to evaluate those not supported by data, so as to classify all risk sources into risk levels. Finally, the fuzzy comprehensive evaluation method was used to realize the comprehensive evaluation of tram operation risk. The results show that the overall risk of tram operation is acceptable, and the risk of equipment, driver and passengers are higher. It is suggested to strengthen the maintenance and health management of key equipment in tram operation, and to take appropriate measures to strengthen the risk protection of passengers and drivers.
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Artistic creation and practice of Beijing Rail Transit public space from a cultural perspective

LI Ya Tie, ZHOU Yi

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Based on the discussion of the relationship between culture and rail transit public space, this paper clarifies that rail transit public space is the carrier of the continuation, inheritance and development of a city's culture. The art of rail transit public space can strengthen the organic relationship between the ground and underground space, and create a cultural atmosphere of the space environment. This paper summarizes and studies the practical experience of public space of Beijing rail transit, summarizes and improves the artistic creation ideas and organization mode of public space of rail transit, and enriches the underground space environment and creates humanistic space through new ideas and methods such as personalized cultural sites, cultural space integration, and modern creation techniques; And two cases of Beijing rail transit public space art creation are used to give practical examples of the views described in this paper, which will provide reference for the future practice of Beijing subway public space art creation and the creation of national subway public art.
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Research of Energy-saving on Intelligent Energy System Based on The Cloud Platform

jiang yue

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IIn order to implement the national strategic goal of "carbon peaking and carbon neutrality", Ningbo rail transit closely follows the intelligent energy construction target of “the Smart Urban Rail Development Outline” by the Urban Rail Transit Association, takes "more energy saving, more friendly and more advanced" as the guidance, takes innovation of the energy saving technology as the core, and takes informatization and intelligence as the means, to carry out in-depth research on intelligent energy system. Presents the construction and implementation scheme of intelligent energy management platform based on the cloud platform and the comprehensive energy-saving technology scheme of "energy supply and energy use" based on the two-way variable current traction power supply technology, special rail return current power supply technology, the permanent magnet synchronous traction technology, the high efficiency and energy-saving ventilation and air conditioning technology, and the intelligent lighting technology Centralized DC Power Supply.
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Research on the defense-in-depth system of integrated network security inside and outside the cloud

shiyongfei

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Based on the current situation of network security construction in the urban rail industry and the research on the application of new technologies in the network security industry at home and abroad, the network security risks of the urban rail cloud are analyzed. Starting from the 20-character policy of guaranteeing compliance and ensuring safety, we will study the construction method of the urban rail cloud integrated network security in-depth defense system, put forward the step-by-step construction steps of security capabilities and the concept of differentiated security capability construction in different network domains, and discuss the urban rail cloud. The security operation maturity model of the security operation and maintenance center and the goals of each stage provide guidance for the subsequent security planning and construction of the cloud platform in the urban rail industry. Through the comparative analysis of innovative technologies such as software-defined security, zero trust, cloud workload, and security operation and maintenance center, the test verifies the innovative application scenarios of related technologies in the urban rail cloud, and analyzes the economic benefits and technologies brought by the innovative technologies. benefit. The research results have good reference significance for deepening the defense-in-depth system of urban rail cloud network security in my country.
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Research on digital urban rail construction management and safety risk control based on BIM

GUAN Bo, WANG Meng, ZHOU Canwei, LIU Xiaofeng, LI Pengfei, LU Xuejia

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Follow with the high-quality development needs of urban rail transit, carry out information-based overall planning and top-level design, compile BIM standard system and management system, and develop a BIM-based construction visualization collaborative management platform and a BIM-based safety management and control system. Relying on the digital management and control based on BIM in the construction stage of the project under construction, taking the BIM model as the data carrier, mining the value of BIM technology, extending the application of BIM technology to the project management level, taking organizational structure innovation as the guide, and reshaping the project with information application The management process is the core, and the digital management platform is used to realize the real-time participation of all management levels, departments, and all employees. The management process is covered by all professions, the whole process is implemented, and the full-dimensional control is realized, realizing the transformation of enterprise management from traditional experience management to digital management and process management. The transformation of management and standardized management, improve the level and efficiency of project management, promote the digital transformation and upgrading of enterprises, and support the strategic transformation of the national transportation power into a transportation power.
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The Enlightenment of Dispatch and Command Mode of Foreign Urban Rail Transit Network to Beijing Subway

YU Dandan, XU Huijie, CHEN Wen, CHENG Hao, LU Kai

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Our country’s urban rail transit (URT) operation enterprises generally adopt the single-line operational control mode, and its shortcomings in management costs and operational organization efficiency are becoming increasingly prominent with the expansion of the scale of line network operation. In response to this problem, Beijing subway is exploring a more scientific and economical new mode of multi-line intensive dispatching and commanding. This paper deeply analyzes the characteristics of dispatch and command mode from the perspective of operation control and dispatching management, then selects the typical foreign subway network dispatch and command mode of "decentralized control, centralized management" and "centralized control, centralized management" as the object, and analyzes dispatch and command organizational structure and systems construction in detail. Finally, the differences between the dispatch and command mode of Beijing subway and the typical foreign subways are compared to form the enlightenment of the construction of intensive dispatching management mode, which provides reference for the construction of centralized, economical and efficient dispatching command system in the URT industry.
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Research and Application of Intelligent Site Information Integrated Management System in Urban Rail Transit

LUO Qingping

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In order to realize the application of the smart construction site platform in the management of rail transit engineering projects, Qingdao Metro Group has carried out a smart construction site information integrated management system platform according to the requirements of the "China Urban Rail Transit Smart Urban Rail Development Outline" issued by the China Urban Rail Transit Association. Research and construction work. This system summarizes, analyzes, mines and utilizes the massive information data generated on the project site by establishing a complete set of asset data, collects on-site information in real time through face recognition, video monitoring, automatic monitoring and other equipment, and uses the front-end perception technology of the Internet of Things and "" BIM+GIS" digital twin technology real-time supervises the elements of "human, machine, material, law, environment" and other elements in the construction process, and realizes the informatization, standardization, Digital and traceable management and control effectively solve the problems of incomplete and untrue information, large amount of manual statistics in traditional methods, information islands between subsystems, etc., and achieve intuitive, dynamic, comprehensive and unified implementation management and control, intelligent analysis and data sharing, Ensure that the concept of "remote visual supervision" is implemented.
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Research on standard urban rail cloud and sharing data platform for ultra large network

wuhao, 梁樑, 张月坤, 田可心, 李申, 熊辉

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Based on the "1811" layout of the outline for the development of smart urban rail transit in China issued by China Urban Rail Transit Association and the action plan for the development of smart rail transit in Beijing led by Beijing Infrastructure Investment Co., Ltd., and relying on the advantageous resources of "government, industry, University and research" of Beijing collaborative innovation rail transit Research Institute Co., Ltd, Study the standardization, autonomy and multi cloud heterogeneous secure and trusted cloud computing platform of urban rail cloud and big data; Build a big data platform system for comprehensive carrying, sharing, mining, governance and quality evaluation of Urban Rail business data, give full play to the circulation, interconnection and interoperability efficiency of urban rail big data elements, and promote the deepening application of Urban Rail business to big data elements and the improvement of data value; Promote the development of smart city rail, build the "three networks" standardized and collaborative network defense in depth technology system and its key symmetric and asymmetric password application technology, and maximize the cloud security capability of urban rail; Study the replicable and highly available cloud platform operation and maintenance normal and emergency management system and mechanism to ensure the business continuity of urban rail cloud, data security and intensive operation and management of cloud platform infrastructure.
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Study on cloud number fusion and cloud security Coordination system of smart urban rail

WangHao

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This paper investigates the research status of cloud platform, data platform and network security in the field of urban rail at home and abroad. At present, there is no reference case abroad, and the integration and cooperation of domestic cloud platform, data platform and network security construction is insufficient. Data platform of the implementation of the requirements under the cloud architecture are analyzed, the research is mainly focused on the cloud technologies stack of database, data platform, cloud platform and data platform convergence, etc., analyzes the overall cloud city rail network security requirements, deepen the cloud was studied in the same system and self-preservation and cloud platform and data platform and network security resource pool together, A unified and collaborative management center integrating cloud platform, data platform, network security, data resources and system operation and maintenance is proposed. The research shows that the overall planning and selection of data platform and the use of software defined security technology can achieve the integration and collaboration of cloud platform, data platform and network security, which can provide reference and reference for the digital transformation and intelligent upgrading of urban rail transit.
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Optimization of Suburban Train Operation Organization Based on Virtual Coupling

HAN Baoming, LONG Yuxuan, ZHANG Qi, BAI Jiawei

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As an important achievement in the development of vehicular communication, virtual coupling technology can effectively reduce headways and provide a more flexible online scheme of coupling and uncoupling, providing a new method for optimizing the train operation organization in the suburban railway. Taking the typical suburban railway line with " one trunk and several branches " as an example, this paper analyzes several traditional methods of train operation organization and then designs a new train operation organization scheme based on virtual coupling technology. Results show that with the same frequency of the main line as other schemes, the virtual coupling and flexible coupling schemes can increase the service frequency of the branch line, save the number of rolling stocks, and reduce the passenger waiting time and travel time. Compared with the flexible coupling pattern, the virtual coupling scheme has more obvious advantages in reducing passenger travel time and the rolling stock traveling kilometers.
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Optimal Operation Plan Design for Virtual Coupled Trains in Urban Rail Transit

YOU Ting, MA Fayun, MIAO Feng, XU Gongde, YANG Zhongping

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Virtual coupling technology realizes "virtual connection" of vehicles through vehicle to vehicle (V2V) wireless communication technology. Since there is no mechanical coupling device such as coupler between vehicles, dynamic marshalling and unmarshalling can be carried out during the operation of vehicles, so as to realize flexible transportation mode based on passenger flow. Based on the comprehensive optimization of passenger travel time and train transportation efficiency, the optimization method of virtual coupled trains operation plan is proposed in this paper. Then, taking an urban rail transit line as an example, the optimization design results are given according to the original-destination (OD) data of morning peak passenger flow. Comparing the virtual coupling optimization plan with the current plan, the results show that the virtual coupling optimization scheme can not only ensure the transportation efficiency, but also effectively shorten the passengers travel time and improve the service quality of rail transit.
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Discussion on the key performance indicators and technologies of virtual coupling in metros

LIU Hongjie, TANG Tao, ZHANG Yanbing, CHAI Ming, LUO Xiaolin

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Virtual coupling has become a hot topic worldwide. It is supposed to be able to enhance efficient and flexible utilization of vehicle resources, and is an effective technology to solve the problem of uneven spatial and temporal distribution of passenger flows in railways. Existing research adopts the idea of vehicle platooning in road traffic and mainly focuses on the methods to keep the stability of train tracking, while this main focus fails to fully meet the actual needs of railways. Aiming at the application of virtual coupling in urban rail transit (hereinafter metro for short), this work first analyzes the real characteristics of metros, based on which summarizes the key performance indicators (KPIs) that should be met by virtual coupling in metros, such as parking time difference and so on. Then, potential application scenarios suitable for virtual coupling are proposed, including large and small routes, Y-topology tracks, etc. Furthermore, key technologies of virtual coupling are introduced, to provide a guidance for future research on virtual coupling in metros.
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Research and verification of protection curve of metro vehicle driven by linear motor

xugongde, MIAO Feng, MA Fayun, LIU Ao, CUI Lei

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Metro vehicles driven by linear motor are not limited by wheel rail adhesion during traction or electric braking. The intervention of electric braking into emergency braking can improve the braking performance. For the sake of safety, the vehicle refers to the protection curve to monitor the electric emergency braking performance in real time. In order to accurately calculate the protection curve, the application process of the actuator was analyzed and the emergency braking performance was modeled in this paper. It was proposed to combine and analyze the theoretical performance of each actuator to obtain the instantaneous theoretical emergency braking performance. Combined with the performance model and instantaneous theoretical performance, the critical condition of electric emergency braking performance was deduced. From the perspective of safety and availability, the critical conditions were optimized and the protection curve of the vehicle was solved. The vehicle test of Beijing Airport Line showed that under the speed level of 110km / h, when the judgment coefficient is 0.92 and the adjustment coefficient is -0.12, the safety margin of deceleration is 2.7% and the safety margin of braking distance is 5.3%, which verifies the safety and availability of the protection curve.
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Statistics and Analysis of Operation and Construction of Fully Automatic Urban Rail Transit Lines in China

Fan Quanyong

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Abstract:

Based on the statistics of the construction and　operation of domestic urban rail transit lines which adapt the fully automatic operation technology, this article introduces the automatic line and line scale, grade of automation for each line and operation starting time, and analyzes the construction and operation mileage growth trend in recent years, mileage and quantity of automatic line in each city, the application of Grade of Automation, and also analyzes the application of signaling system supplier and train supplier on the automatic line. The data shows that by the end of 2021, a total of 24 cities in China have built 65 fully automatic lines, with a total construction mileage 1913 kilometers, of which 15 cities have 29 fully automatic lines put into operation, with a total length of 932 kilometers. There are 58 lines adopt GOA4, accounting for 89.2% of the total number of automatic lines, with a mileage of 1683 kilometers, accounting for 87.9% of the total mileage; There are 7 lines adopt GOA3, accounting for 10.8% of the total number of automatic lines, with a mileage of 230 kilometers, accounting for 12.1% of the total mileage. GOA4 has become the preferred choice for fully automatic lines. There are 11 signal suppliers and 10 train suppliers that have been used in domestic automatic lines, most of them are domestic suppliers, and they have realized independent intellectual property rights, which are conducive to the rail transit technology and equipment innovation.
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Review and reflection on TOD construction and development of urban rail transit in China in 20 years

YWZZ

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China"s urbanization provides opportunities for urban rail transit construction, and rail transit has also boosted urbanization to a new height. Especially since 2000, the 20-year development of rail transit TOD has become a highly concerned phenomenon. Both practical and theoretical levels are trying to clarify the internal mechanism and operation rules of TOD. This article from the perspective of China"s urbanization development of rail transit TOD walked the path and function, review of orbital TOD from introduced "learning" to "practice" to the "innovation and development" of course, combed summarizing its development regularity and the characteristics of the practice in China and contribution, thinking track TOD in the new stage of urbanization and the development trend of future direction.
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Planning and development suggestions for the integrated development of Beijing suburban railway and the city

lanyajing

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As a large capacity rail transit system, suburban railway plays an important role in supporting the development of modern metropolitan area, improving the regional comprehensive transportation carrying capacity and ensuring the efficiency of long-distance commuting. For a long time, how to strengthen the integrated development of suburban railway and city has been the focus of Beijing rail transit. This study systematically analyzes the operation characteristics of Beijing current suburban railway, from the perspective of mining important factors that affect the passenger flow benefits, it is concluded that the main factors such as the location of the line's starting and ending points, the connection between the station and the urban traffic network, and the rail service level represented by the departure frequency. Based on the strategic analysis of the future development of Beijing population employment, urban functions, spatial structure and other macro issues, in order to further strengthen the integrated development of Beijing suburban railway and the city, put forward important suggestions on the planning of Beijing suburban railway.
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Influence analysis of anchor bolt foundation of high-rise building under mining tunnel

LI Yanchun, WU Ze

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In order to ensure the safety of the mining tunnel passing through the shallow foundation elevation building and ensure that the anti overturning ability of the elevation building is not weakened, this paper uses the finite element analysis method and combined with the specification requirements to analyze the impact of the building anti pull anchor foundation in the process of the tunnel passing through the shallow foundation elevation building, compare the stress state of the anchor foundation before and after the stratum reinforcement, and analyze the effect of stratum reinforcement. According to the finite element analysis and the calculation of the standard formula, the tunnel excavation causes the displacement and deformation of the stratum around the anchor foundation towards the tunnel direction, which plays a tensile role on the anchor foundation, resulting in the reduction of the anti overturning safety factor of high-rise buildings. The stratum grouting reinforcement measures can effectively reduce the impact of tunnel construction on the anchor foundation, and the grouting range can be optimized according to the influence line of tunnel construction.
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Model Predictive Control on Air-conditioning System in Subway Stations and Energy Saving Analysis

XING HAN

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As the energy consumption of rail transit grows rapidly, energy saving has become an important system in subway station. In this paper, the current control method of air-conditioning system was analyzed, and then propose a new model predictive control method. The rolling prediction method, optimization objective and restraint conditions, and global optimization methods were described. The method was analyzed in a simulation and showed that the energy consumption was lowered 12.7% and the peak power demand in summer was lowered 35%.
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Practice and Thinking of Digital Transformation for Xiamen Rail Transit Construction

Shi Yongfei

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Digital transformation is an important means to reduce cost, improve quality and increase efficiency in rail transit construction. Based on the in-depth analysis of the prominent problems existing in the production and operation process of the traditional rail transit industry, and starting from the digital transformation practice of Xiamen Rail Construction Development Group Co., Ltd., this paper expounds the overall process and digital practice process of Xiamen Metro in the construction process. Xiamen Metro has explored the feasibility and innovation of organic combination of traditional engineering construction and digital technology, and formulated the implementation path of building digital base, carrying out data governance, building smart Metro and improving enterprise management. At the same time, Xiamen Metro has made a preliminary attempt to carry out digital transformation construction in information model, intelligent passenger service, intelligent transportation organization, traffic economy, etc., which not only promotes the transformation of enterprise management mode and the progress of intelligent scene application, but also lays a good digital foundation for the high-quality sustainable development of enterprises and rail transit industry.
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Study on Surface Settlement of Down-top Excavation of Beijing Metro Auxiliary Project Ye Xinfeng_^1,_², Chen Bo_³, Guo Xin_³, Liang Haiying_^1,2,Gong Yaona_^1,2

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Abstract:

The down-top excavation method is used for elevation climbing section of the metro station ancillary project ,due to the restricted by the construction duration, the lack of ground space, the existing connection and other conditions.Through the statistic analysis of the down-top excavation construction settlement rule and influencing factors, and the settlement law was explored by comparing the measured analysis and numerical analysis of the down-top and dig-down two excavation cases. The results show that: 1) The arch is sandy soil ,87.3% of the measurement point settlement amount is between 3~ 60mm.The arch is clay soil ,59.2% of the measurement point settlement is between 3~ 30mm. The arch is pebble layer ,the measurement point distribution is dispersed.2) The arch is the relationship between the amount of sedimentation and the buried depth when the clay soil is clay and sandy soil, and the relation is basically proportional linear when the arch is pebble. 4) The maximum settlement of the down-top excavation construction is about 75% of the dig-down construction, it occurs in about 1/2 of the climbing section, and the maximum settlement of the dig-down construction is closer to the lowest depth. The conclusion of the study can be used to make a preliminary judgment on the range of subsidence and the most unfavourable part of settlement control.
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Research on the Application of MJS combined with Micro-disturbance Grouting in the Renovation of Convergence Deformation of Subway Tunnel

CHEN Pu, WU Yong, YANG Kang, ZHANG Xiao, DING Zhi

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In order to further improve the renovation effect of the convergence deformation of operating subway tunnel, the renovation technology of MJS combined with micro-perturbation grouting is proposed, and is applied to the construction project of the convergence deformation renovation for an operating subway tunnel in Hangzhou. By analyzing the measured data of tunnel deformation before and after the renovation technology, the effects of joint renovation on operating tunnels are discussed, and the tunnel deformation laws caused by micro-perturbation grouting are summarized. The research results show that the renovation technology of MJS combined with micro-disturbance grouting has a significant effect on the convergence deformation of subway tunnel, and it effectively solves the problems of secondary rebound of tunnel convergence after grouting and additional deformation during the grouting; Micro-disturbance grouting construction shall focus on ensuring the construction quality of the twice grouting and controlling the interval time of the same grouting hole.
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ZHOU Juhong1, LIU Jianwei1, YIN Jie1, CHEN Zhaohui2, JIA Pei2,ZHOU Haiqi3，FENG Ding3，LIN Sheng3

ZHOU Juhong, LIU Jianwei, YIN Jie, CHEN Zhaohui, JIA Pei, ZHOU Haiqi, FENG Ding, LIN Sheng

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Abstract:

In order to realize the reactive power balance of the power supply system of Guangzhou Metro Line 18, according to the topology of the line, the causes of excess reactive power are analyzed, the reactive power level of the line power supply system is calculated, and the compensation capacity and compensation mode of the reactive power compensation device in the line are considered. The reactive power compensation method based on enumeration method and particle swarm optimization algorithm is proposed, and the reactive power compensation strategy is given. Combined with the data of Line 18, the simulation results show that the reactive power compensation strategy proposed by the above methods makes the reactive power of the power supply system get a good balance.
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A New Excavation Method of Large Section Deep-buried Rail Transit Stations-Bench Cut Method with Expanded Arch Feet

ZHOU Jie, ZOU Guangjiong, PENG Hui

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Abstract:

To adapt the new environment and new situation of Chongqing rail transit construction, combined with the topography, geological conditions and characteristics of rail transit stations in the main urban area of Chongqing, this paper proposed a new construction method of large section deep-buried rail transit stations- bench cut method with expanded arch feet. Based on the New Austrian Tunneling Method as the theoretical basis, this construction method gives full play to the self-stabilizing ability of the surrounding rock and the space constraint of the excavation surface, and the load is transferred to the surrounding rock by the setting of the large arch feet of the primary lining to improve the bearing capacity and stability of the arch area of the primary lining. At the same time, through the step-by-step excavation, sufficient construction space is provided for the excavation of large-section tunnels, which effectively improves the construction efficiency of the tunnel and saves project investment and construction period. This paper takes Hongyancun Station of Chongqing Rail Transit Line 9 as a case to compare and analyze this construction method and the double side drift method. Through theoretical calculation and analysis, it can be concluded that bench cut method with expanded arch feet has less disturbance to the surrounding rock, which is more beneficial to the protection and deformation control of the surrounding rock, and the engineering risk is also more controllable.
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Study on Application of Ultra-high Pressure Jet Grouting Water Stop in Underground Excavation Station in Pebble Stratum

鲍凯, 苑伟家

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In order to study the water stop effect of ultra-high pressure rotary jet grouting technology in the underground excavation of station by PBA method in pebble stratum, the on-site rotary jet grouting test was carried out, the conventional construction equipment was improved, the construction sequence was optimized, and the mechanized hole leading and shotcrete pile forming operation in the narrow space of side pilot tunnel of underground excavation station were realized. The test pile results show that the reinforcement diameter of pilot test piles in pebble stratum is more than 1m; The maximum impermeability coefficient of the reinforcement is 2.902×10-14cm / s, meeting the requirements of no water seepage of the project; The compressive strength of the reinforcement is more than 24MPa, and the reinforcement effect is obvious, which can effectively improve the bearing capacity, strength and overall stability of the stratum.For the first time, the application of ultra-high pressure jet grouting technology in Beijing underground excavation station in pebble stratum has been realized. This method has achieved good water stop effect in the engineering practice of wanquanheqiao station, and has important guiding significance for the water stop treatment of underground excavation station in Beijing.
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Research on The Setting Method of Rail Transit Real-time Passenger Flow Alarm Threshold Based on Isolation Forest Algorithm

Wang Yueyue, Sun Qi, Zhong Houyue

Abstract: (158) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

In the rail transit real-time passenger flow monitoring business, a station real-time passenger flow alarm is to help the operator quickly and accurately locate the station that may have a significant passenger flow risk in the network to achieve the role of early warning. If the alarm threshold is too small, the alarm frequency will increase so that the operator cannot accurately judge the high passenger flow risk station that needs to be paid attention to most and have a numb mentality to the alarm prompt; if the alarm threshold is too large, the risk of sudden large passenger flow in the station may not be monitored, and responses cannot be taken in time. Therefore, the primary purpose of this paper is to propose a set of scientific, reasonable, and applicable alarm thresholds. This paper uses the traditional statistical method and the isolation forest method based on machine learning to train and set the alarm threshold. In addition, the two algorithms are compared through the application effect test. It is confirmed that training the outliers in the isolation forest ensures that the alarm threshold is more aligned with the business goals. According to the principle of "one station, one plan" and "one time period, one plan", the research results of this paper provide the alarm threshold of the station’s real-time inbound and outbound volume for the dispatching emergency command, passenger guidance and information service platform of the Beijing Metro Network Control Center(BMNCC), and support the real-time monitoring of passenger flow and the risk early warning of large passenger flow.
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Safety Risk Assessment of Subway Station in Integrated Transportation Hub Based on FTA-BN

姚诗忆, 汪益敏, 仇培云, 陈嘉诚, 农轲

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This paper takes the subway station safety in the integrated transportation hub as the research objective, and comprehensively considers the special passenger flow composition and passenger characteristics in the integrated transportation hub. Taking five types of prone risk accidents as the research objects: stampede, fire, flood, public health, and large-area detention. Analyze its influencing factors based on the FTA-BN method, identify its risk factors, establish a corresponding fault tree model, and transform it into a Bayesian network model for risk assessment. The prior probability and conditional probability distributions in Bayesian networks are obtained by introducing expert natural language for triangular fuzzy number processing. Then the Bayesian network model is used to perform network reasoning calculations and sensitivity analysis to find the weak parts in the subway station, and formulate corresponding risk control measures, so as to improve the ability of the subway station in the hub to respond to emergencies. Taking The subway station of Guangzhou South Metro Station as an example, the rapid evaluation results show that Guangzhou South Metro Station has a certain risk in terms of public health safety, with a probability of 42.98%, and is prone to large area detention, with a probability of 30.40%.
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The demonstration and application of large-section pipe-jacking in subway parking line

SU Jiangchuan

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Excavations of subway parking lines are usually constructed with the method of open cut witch is also widely applied in excavations of subway stations. With the development and improvement of urban infrastructure, the problem of open cut, such as taking huge working area, causes greater impact towards surroundings. Based on subway parking wiring optimization and construction methods demonstration, this paper proposes to use rectangular-section pipe-jacking tunnel to avoid this problem taking some Fuzhou Metro interval construction as an example. Considering need of many related specialties and structure safety, the size of the pipe-jacking tunnel comes to 10.8m×7.5m. According to practice: the total length of pipe-jacking tunnel is around 190m, the rate of excavation is around 54m per month. The total deformation of ground surface along the tunnel is -17mm~2mm. This demonstration and application provide reference and experience for similar engineering utilities of super large section pipe jacking tunnel in future.
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Enlightenment of Shenzhen Metro line 11 construction and operation to Shenzhen Express Line Construction

yangbin, GUO Li

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In order to solve the problem of inconsistency between the planning goal and the construction effect in the process of urban rail express line planning and construction in China, this paper combs the planning and construction of urban rail transit express line in Shenzhen, taking Shenzhen metro line 11 as an example, this paper analyzes the impact of express line on urban spatial structure, employment, housing and development along the line, the connectivity of express line network, and the standards and construction effects of express line. It is concluded that the construction and operation of Line 11 promoted the westward movement of the city center, optimized the land use properties along the line, strengthened group connections, accelerated network integration, realized the 30-minute connection between the central city and the airport, and played the integrated development role of the express line to the city. On this foundation, this paper analyzes and propose that the construction of urban rail transit express line should match with the spatial structure of urban planning, synchronize with urban development and construction, pay attention to the connection of network and the construction standard of express line need to be improved urgently, and there should be restrictive development proposals. It provides ideas and references for the construction and development of Shenzhen and other urban rail transit express lines.
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The Impact of Urban Rail Transit Vehicle Base land Planning on Its Comprehensive Development Performance

Lu Yuan, lixinru, 邵金雁

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The planning layout and land scale of the land use plan of the rail transit vehicle base have a significant impact on the feasibility and economy of its comprehensive development. On the basis of the analysis and summary of the comprehensive development characteristics and development status of the vehicle base, taking Beijing, Nanning and other cities as an example, the planning layout and land use scale of the typical vehicle base are studied, and it is found that due to the subjective factors of the vehicle base cycle, high cost, low compatibility, strong sensitivity to development performance and other process attributes, the remote planning layout, the lack of supporting facilities to limit the expected benefits, and the mode of single choice of land for major projects has caused institutional bottlenecks. Objective factors of land use planning, such as simple land-saving design and increased development costs, limit the implementation effect and comprehensive performance of comprehensive utilization of vehicle bases. Based on this, suggestions are made for the improvement of the lack and misalignment of the vehicle base in terms of functional positioning, site selection standards, land use procedures, planning and preparation.
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Research on temperature prediction of subway transformer windings based on LSTM

Wen Jianmin, He Bin, Wang Kaikang, Ye Fei, Liu Hongjian, Chen Jie, Liu Zhigang

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The traditional subway condition monitoring system can only reflect the current temperature state of transformer winding and its historical temperature trend. When the winding temperature exceeds the threshold, the system will give an alarm. But the system can not predict the future temperature change of the transformer and the change of equipment operating state. The winding temperature is affected by multiple factors such as operating power and ambient temperature, and its change is nonlinear and periodic. It is difficult to improve the accuracy of traditional prediction methods. With the development of deep learning technology, the transformer winding temperature was predicted based on the Long Short-Term Memory (LSTM) algorithm. The winding temperature, ambient temperature, operating power and operating current were selected as input variables, and the historical state data of the transformer were collected to form a large amount of training data for off-line training. The relationship between multiple influencing factors and winding temperature was reflected by the transformer temperature prediction model. Finally, the algorithm was applied to subway power transformer. The sample data were collected for training to obtain the temperature prediction model. The test data was input into the trained model. The relative temperature difference between the real value and the predicted value of winding temperature was calculated to analyze and verify the feasibility and accuracy of the algorithm. The results showed that LSTM algorithm could fully mine the deep relationship between multiple influencing factors and winding temperature in the face of large data samples. The temperature prediction model can accurately predict the changes of winding temperature.
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Case Analysis and Optimization of Rain Water Storage on Platform of Depots

YANG Xiaojuan, JIANG Qin, HUANG Yun-feng, LIU Qing, LEI Yusha

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In view of the problems and characteristics of large rainwater catchment area, large runoff coefficient and large municipal impact load before development of the development platform on the upper cover of the vehicle base of Rail Transit, based on a concrete design case of rain water regulation and storage with a cover plate platform on a vehicle depot in Xi"an, this paper puts forward the design idea of using the cover plate of the vehicle depot as a rain water regulation and storage tank from the angles of rationality, compliance, safety and economy, by increasing the height of the sidewall of the gutters and reducing the diameter of the storm water pipe at the bottom of the gutters, the purpose of storing and draining the gutters at the edge of the gutters during rainfall is achieved. The analysis shows that the scheme is safe and reliable, and has the practical effect of saving land, saving investment and reducing waterlogging around the depot.
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Research and Application on Schedule Risk Management in the Project Planning of Urban Rail Transit

Li Heng, Yue Tongxing

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In order to ensure that the Chengdu Metro Line 5 project put into operation on schedule, risk management methods are applied in the project planning to refine the construction schedule. The brainstorming method is used to identify the risks, the risk matrix method and analytic hierarchy process are used to evaluate the risks qualitatively and quantitatively. We research on a major risk as an example and provide risk solutions in detail: the difficult transportation and erection of box girder in viaduct projects. The application of risk management in the planning of Chengdu Metro Line 5 project is an innovation and breakthrough. It has been effectively verified and can provide reference experience for similar projects.
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Study of Energy-saving Slop Optimization of Metro Profile in Cruising Mode

Yang Dongying, 易思蓉, 王仲林, 刘德卫

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Cruising mode is a common method used by metro trains for safety, comfort, and punctual operation. However, the manual design of vertical alignment is hard to fit with the cruising state and the variation of design conditions, which means ineffective energy saving. This paper defines mileages and elevations of the gradient change points, sets up a vertical alignment optimization model based on the objective of minimum traction energy consumption of double directions, and utilizes a differential evolution algorithm to solve the optimization model. The optimization strategy includes two stages named initial alignment search and adjustment. The appropriate number of gradient change points are set according to the interval length in the stage of initial alignment search, and the gradient change points with small gradient differences on the initial alignment are deleted in order to get the finial optimal alignment. The optimization result reveals that the energy saving of double directions could be small while the energy-saving slopes are steep and the middle slopes are gentle. The sensitive analysis reveals that the length of the energy-saving slop should be large if the coasting length is large. If the elevation difference of stations is large, the gradient and length of energy-saving slop adjacent lower station should be small, and the length of energy-saving slop adjacent higher station should be larger.
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Quantitative study on optimization of land use pattern in TOD region of urban rail transit

hedewen, lengsen, zhouzeyan

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In the rail transit network of the same city, how the traffic corridor effect between the traffic stations along the rail transit line or adjacent lines will affect the optimization of land mixed development and utilization in the TOD area of urban rail transit is the problem discussed in this paper .The mixed-use planning of the TOD area of urban rail transit stations should consider the interaction between urban rail transit lines and stations, and consider the TOD area of rail transit stations with linkage effects as a whole for land use function planning.This paper adopted the method of quantitative analysis to analyze the TOD degree of land use around rail transit stations.Within the TOD area of urban rail transit, used CAD tools to identify the status quo of land use, and use DPSO to determine the utilization mode and floor area ratio of undeveloped land, so that the land use in the TOD area of rail transit took into account the high level of connotation of TOD concept. The principle of density development also took into account the humanized design principle of the comfortable environment of "Park City".The study selected four commercial core rail transit TOD areas in Chengdu to evaluate the degree of mixed use planning of empirical land, and found that rail transit TOD areas with higher accessibility were more inclined to plan a large number of residential and commercial land,while the lower areas’ planning was similar to the general independent planning of rail transit TOD areas, and various types of land were more balanced.
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Study on the management of abnormal rail corrugation in underground foundation vibration reduction section

YANG Guangwu, GUO Jianping

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Aiming at the problem of abnormal rail corrugation caused by subway lines, this paper investigates the rail corrugation situation and basic characteristics of a subway line, tests the track stiffness, rail profile, gauge and track dynamic characteristics, puts forward the treatment ideas of abnormal rail corrugation, tracks and tests the treatment effect of rail corrugation, and puts forward the treatment and prevention schemes of rail corrugation in existing and newly-built subway lines. The results show that the wave grinding of subway rail is serious, and the wavelength is between 25 and 100 mm; The vertical and lateral stiffness of the track is weak, the rail displacement is large, the ability to keep the gauge is poor, the wheel-rail relationship deteriorates, and the wheel-rail vibration intensifies in a specific frequency range, which leads to the emergence and development of rail wave grinding. By replacing fasteners and pads, fine measurement and adjustment of track, and rail grinding measures, the noise inside the car can be reduced by 5~10dB, the rail roughness can be significantly reduced, and the grinding period can be more than doubled. The existing lines can be treated by "detailed investigation, parameter adjustment, fine maintenance and dynamic inspection". The newly-built subway lines should be strictly controlled in the stages of planning, design, operation and maintenance and dynamic acceptance, and the vibration-damping track should be reasonably adopted to avoid the occurrence and development of abnormal rail wave grinding.
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Interaction and Correlation Analysis Between Subway Station Behavior and Space

Guo Xiaoyang, Peng Zhuo

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At present, the integration of cities and transportation is developing rapidly, and the functional attributes of a large number of subway stations have been transformed, which cannot meet the behavior and activities of users. In this study, the spatial elements in the subway station domain are used as the interactive object, the user behavior activities are used as the interaction subject objects, and the Guangji South Road station area in Suzhou City is used as the research case, and the GPS real-time tracking and behavior annotation are carried out for the user behavior activities, and the data is imported into the GIS software to achieve data visualization and analysis. By analyzing the behavioral characteristics, spatial characteristics and temporal characteristics of users in the subway station domain space, the influencing factors of the initiation stage and the feedback stage in the interaction process of the two are explored, and the correlation between the behavioral activities and the spatial elements is analyzed, so as to provide support for subsequent theoretical application and optimization strategies.
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Research on construction of Intelligent integrated Emergency Management System for urban rail Transit

LIU Xinke, WANG Guanqiong, ZHUANG Yin, WANG Yali

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In view of the characteristics of urban rail transit emergencies, comprehensively considering the needs of emergency management informatization in the construction and operation period of urban rail transit. The key technologies, design principles and system architecture of intelligent integrated emergency management system are expounded This paper introduces the construction of the main function modules of emergency map, emergency guard, emergency warning, auxiliary decision, emergency command, material dispatch, emergency drill, etc. The system enables the sharing of important resources such as emergency supplies, emergency teams and emergency experts during the construction and operation period. The functions of automatic emergency warning, auxiliary decision-making, and recommendation of the optimal emergency rescue route can significantly improve the emergency response capacity and disposal efficiency.
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Technology of high rigidity and low reinforcement prestressed shield tunnel structure

shield tunnel structure

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At present, the general practice of shield tunnel at home and abroad adopts the method of segment segmentation and bolt connection. In this way, the circumferential and longitudinal overall stiffness of shield tunnel is highly dependent on the stratum, and the integrity and ovality are greatly affected by the disturbance of the stratum, especially in soft soil areas. At the same time, the reinforcement of segments is relatively large. This paper puts forward a technology of prestressed shield tunnel with strong stiffness and low reinforcement, which can effectively solve the self defects of low stiffness and insufficient deformation resistance of shield tunnel in theory, and fundamentally improve the integrity, deformation resistance, stability, bearing capacity and water resistance of shield tunnel. According to the calculation and analysis of the same working condition, different stratum conditions can provide no less than 45% optimization space on the basis of the reinforcement of the existing shield segment, and ensure the structural safety and reasonable stress.
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Study on Evaluation Method of Core Subsystem Safety Integrity Level of the FAO System

ZHONG Weiqiang, LIU Chao, HUANG Kangqiang, LIU Qiyang, HU Feiyan, GONG Taoyi

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In order to explore how to evaluate the functions safety integrity level (SIL) of the core subsystem of the fully automatic operation (FAO) system more practically, by studying the structure of the risk model in the European Committee for Electrotechnical Standardization (CENELEC) standard, the definition of risk reduction factor (RRF) is given. Through the defined RRF, the conversion relationship between the tolerable accident rate (TAR) and the tolerable hazard rate (THR) is established, and then the THR of the secondary hazards of the core subsystem functions of the FAO system is evaluated. Through the corresponding relationship between THR and SIL, the functions SIL of the core subsystem is obtained. Application results: Combined with the actual application results of FAO engineering project, specific examples of each element in RRF are given for reference. Compared with the method of conservatively estimating SIL by directly using TAR, the SIL estimated after considering RRF is closer to reality condition.
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Planning and Design Research of Express/Slow Line of Beijing Rail Transit PINGGU Line

WU Haoling, WANG Jingfeng

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With the continuous accumulation of economy, industry and population in urban agglomerations and metropolitan areas, suburban railways are developing rapidly. Taking the planning and design of express/slow line of Beijing Rail Transit PINGGU Line as an example, it is recommended to set different speed target values for different line sections in combination with the length of the line and the conditions of stations along the line. Taking into full account factors such as passenger flow characteristics, passenger convenience, and convenient operations management, it is recommended to adopt the 3-routing scheme in the long-term. The express line stops are determined based on factors such as the boarding and alighting scale of each station during peak hours, the functional orientation of the stations, the main transfer stations, and the planning time target. The passenger flow of the PINGGU line has an obvious tidal phenomenon, so it is suggested that the asymmetrical departures be organized up and down direction during the morning peak. Combined with the planning time target and auxiliary line scheme, it is planned to operate 4 pairs of express trains in the morning peak in the long-term.
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Research on control index and limit value of vertical deformation of ballastless track of long-span bridge of Suburban Railway

li qiuyi

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In order to solve the problem of laying ballastless track on long-span bridges of Suburban Railway, taking Yongning bridge (140+200+260+140) m of Wenzhou Suburban Railway S3 line as an example, combined with the vehicle line bridge coupling dynamic response analysis model.The vertical deformation control standard of ballastless track laid on long-span bridges of urban railway is put forward, and the dynamic response analysis under various working conditions is carried out for the ballastless track on the bridge that meets the corresponding limit requirements.. The specific conclusions are as follows: (1) The vertical deformation requirements of the bridge, the curvature radius of the vertical deformation of the bridge, the transverse deformation requirements of the bridge, the deformation requirements of the beam end and the smoothness of the rail surface all meet the technical requirements for laying ballastless track; (2) When the train passes through Yongning bridge, the indexes of driving safety and riding comfort meet the requirements; 10m chord height irregularity meets the specification limit. (3) The research results can provide reference for the laying of ballastless track for long-span bridges of Suburban railway.
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Design of LCB circuit improvement scheme for platform door local control box of fully automatic operation line

Jia Ping, Liu Dewei, 杨志慧

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In order to identify the possible safety risks in the platform door control circuit during the receiving and departure of the fully automatic operation line, through the analysis of the relevant external interface control circuit of the platform door control system that controls the automatic receiving and departure conditions, the internal "door closed and locked" state safety circuit, and the working mode of the local control box, and in combination with the structure and control mode of the platform door control system, This paper analyzes the possible risks of the existing circuit, especially the circuit design of the platform door local control box, in the application of fully automatic operation, and gives the advantages and disadvantages analysis and improvement scheme design of the existing circuit of the platform door local control box circuit of the fully automatic operation line according to the identified risks. On the premise of considering the safety and operation efficiency, it gives the recommended scheme suitable for the fully automatic operation line.
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Research on the Collaborative Framework System of Metro and Bus Travel Information Service

WANG Hansong, WU Zhongyi, LIU Xianglong, HE Xiang

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In view of the problems of unimpeded sharing of metro and bus travel information, low data quality and poor information service experience, focus on key business links such as information collection, processing and release, the information subject, information object, time and environment of metro and bus information coordination were system analyzed. A collaborative framework system of metro and bus travel information service is proposed. The framework of travel information service system covering resource integration, information system and front-end application is designed. Based on the comparative analysis of the advantages and disadvantages of the traditional travel information service system construction mode, put forward the construction mode and implementation path of "government guidance and enterprise participation". It is expected to provide reference for the design, development, construction and operation of metro and bus travel information service system.
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Research on optimization of stop strategy suitable for operation of express-local train of Suburban Railway

ZHANG Zhao, WANG Wei, SHI Zhu, LIN Zhengnan, HUANG Youneng

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Suburban Railway has the characteristics of high-speed and public transportation operation. Compared with the stop strategy of express-local train operation on subway lines, Suburban Railway has the characteristic of multiple overtaking.Firstly, this paper analyzes the reasons for multiple overtaking of Suburban Railway,next, based on the impact of multiple overtaking on the waiting time of passengers , the minimum total trip time of passengers is taken as the optimization objective. Then, construct the optimization model of the stop strategy under 1: N of express-local trains. Modeling with the coyote optimization algorithm. Finally, the simulation calculation is carried out based on the actual line operation data. Under the condition of meeting a certain departure interval, compared with the only local trains, the total time of passengers onboard can be reduced by 22.25% and the total trip time of passengers can be reduced by 8.82%. The results show that the stop strategy proposed in this paper is effective for the operation of express-local train of Suburban Railway.
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Laboratory Testing and Applicability Study on Mono-Mortar for TBM Tunnel under Soft Ground Condition

Zhang Haiyan

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From the perspective of groundwater protection, surface vegetation protection and tunnel structure durability, mono-mortar caters for the demand of ecological environment protection much more. Based on this reason, the article carries out tests of horizontal slump, oedometer, bleeding, setting time, unconfined compressive, etc. on mono-mortar which can be applied to lean clay and mixed-grained soils. The paper aims to study the physical and mechanical properties of mono-mortar, raising solutions for problems such as the difficulties of estimating early strength, the uncontrollability of hardening time, and the easy blockage of grouting pipeline. The results show that: the measured grouting pressure loss caused by friction, viscous resistance between the mortar and pipeline is 0.16bar, which can be negligible compared with the grouting pressure; the performance development of mono mortar can perfectly meet tight time schedule for TBM heading efficiently; the bear capacity of mono-mortar rises with the increase of the oedometer pressure; the comparison of predicted value and the monitored value of ground settlement verifies the reasonability of the oedometer test theory that mortar can bear strength under a certain pressure in annular gap grouting process.
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Study on Morphological Characteristics of Rail Transit Sites Based on Space Syntax：Taking Three Subway Station Areas in Guangzhou as Examples

LING XIAOHONG, WANG Ying

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In response to the problems of insufficient coupling between traffic stations and spatial forms, poor walking environment, and functional inadaptability during the implementation of TOD in the cities of China, this study, by employing the theories and methods suggested by space syntax, takes three subway stations of Guangzhou, including Zhujiang New Town, Gongyuanqian and Changshou Road as examples. Through comparing and analyzing their configurational properties as well as their relationship with station layout, pedestrian movement pattern, construction intensity, and functional distribution, this study aims to examine the morphological development characteristics in light of TOD principles, subsequently identifying problems arising from the process of implementation. As a result, this study has revealed that the gridding level of Zhujiang New Town Station area is insufficient, and the coupling and interaction between the station and spatial configuration is relatively poor. By contrast, the configuration of Gongyuanqian Station area is highly accessible, and its effect on accumulating activities is considerably strong, but there is a certain degree of incompatibility between the functional distribution and the spatial organization. Changshou Road Station is located in the old urban district, and its background network tends to be continuous and uniform, which is beneficial for pedestrian movements at the community level. Based on the above analysis, this study suggests that future development of rail transit station areas in China should pay more attention to the generative effect of spatial configuration on movement patterns, and improve the synergy among station planning, functional distribution and urban configuration.
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Study on energy-saving potential of ventilation and air-conditioning system of PSD subway stations

SU Ziyi, LI Xiaofeng

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With the rapid urbanization and the proposal of carbon neutralization goal, the energy conservation of subway stations has become the focus in China. In order to clarify the energy-saving potentials of various operation measures for subway stations, this study conducted large-scale simulations on annual energy consumption of ventilation and air-conditioning (VAC) system for platform screen door (PSD) subway stations in different climates. Based on this, the energy-saving potentials of optimizing operational-related parameters to the leading value were analyzed systematically and quantitatively, including cancelling mechanical fresh air supply, enhancing PSD airtightness, increasing air-conditioning temperature, increasing COP of the chiller and increasing EER of terminal equipment. Results show that for subway stations in the studied climate regions, operation measure with the greatest energy-saving potential is increasing air-conditioning temperature, with the energy-saving potential ranging from 17% to 21%; energy-saving potentials of cancelling mechanical fresh air supply, increasing COP of the chiller and increasing EER of terminal equipment range from 12% to 20%, with differences for stations in different climate regions; the measures with the lowest energy-saving potential is enhancing PSD airtightness, with the energy-saving potential ranging from 1% to 4%. Besides, by optimizing all of the above operational-related parameters to the leading value, the energy savings of the VAC system for PSD subway stations in cold region, hot-summer cold winter region and hot-summer warm-winter region areas can reach 220 MWh/year, 370MWh/year and 610MWh/year, respectively, with 41%, 48% and 52% of the energy-saving potentials, respectively.
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Older adults’s metro travel satisfaction and implications for metro improvement

YANG Linchuan, TANG Xianglong, SHI Yaling, LIANG Yuan, YAN Qinran

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The population in China is aging at a rapid rate, which has attracted great considerable attention from, inter alia, policymakers and scholars. Implementing the national strategy “actively coping with population aging” and meeting the multilevel and diversified needs of older adults are now important tasks of governments in China. Moreover, mobility is the crucial determinant of the quality of life and subjective well-being of older people, and the metro is their oft-used travel mode. This study conducts a questionnaire survey data to collect the metro travel satisfaction data of 270 older Hong Kongers, applies a random forest model to estimate the importance of each service quality attribute to the overall service quality, and adopts an “importance-satisfaction” index to identify the improvement priority toward an age-friendly metro system. We find that older adults are generally satisfied with the metro service. They attach great importance to waiting conditions, priority seats, and travel stability but pay little attention to service frequency and reliability. Notably, priority seats, internal temperature, and accessibility to stations are the top three attributes in need of enhancement. Accordingly, practical implications for age-friendly metro improvement are put forward.
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The Formation of Market-Driven TOD Corridors: A Case Study of Bangkok in Thailand

Zhang Chun, Liu Zhi

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Driven by the market forces, the development of urban rail transit can induce the formation of TOD (transit-oriented development) corridors. The development of urban rail transit system in Bangkok started in the 1990s. It was planned and designed to alleviate the severe traffic congestion problem in the central part of the Bangkok Metropolitan Area, without consideration and plan to guide land use efficiency improvement. However, driven by strong market forces, the land use patterns along the rail transit corridors have undergone profound changes over the past two decades. By tracking the land use change based on remote sensing data, this paper explores the characteristics of real estate redevelopment, the changes of land use functions and densities along the rail transit TOD corridors, and the process of land value uplift. It also analyses the establishment process of TOD corridor taking the central part of BTS lines as example, and explores the impact of walking accessibility improvement on the viability of businesses in the central city. Through the case study of Bangkok, the paper reveals how the market forces underpin the transport and land use interaction and drive urban regeneration process spontaneously. It also discusses market-based TOD planning approach, and its role in optimizing the relationship between transportation and land use.
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Design and Availability Evaluation of Next Generation Train Control Data Communication System Based on LTE-M

wanghao

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Compared with the traditional Communicated Based Train Control (CBTC), the next-generation train control system has the advantages of reliable architecture, fast speed, low cost, and high quality of service. Availability can guarantee the safe and efficient operation of trains. This paper is oriented to the next generation train control system. First, the structure of the communication system based on LTE-M is designed; secondly, for the typical scenarios of the next-generation train control system, use deterministic and stochastic Petri nets for availability modeling, and then use π-Tool for model solution and availability evaluation. The simulation results show that the next-generation train control data communication system based on LTE-M proposed in this paper can meet the actual communication needs, and its availability analysis method can complete the availability modeling and evaluation of the data communication system.
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Review of the development of urban rail transit power supply system under the carbon peak and neutrality goals

liguoqing, gaodongsheng

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Under the background of achieving the carbon peak and neutrality goals, this paper comprehensively discusses the development trends of urban rail transit power supply system. Several reasonable suggestions are put forward for the future development of urban rail transit power supply system. First, applications of clean energy and regenerative braking energy technologies in the urban rail transit are summarized. The effect of photovoltaic power generation and regenerative braking energy utilization on energy saving and carbon reduction is analyzed according to the measured data of operational lines. According to the characteristics of different traction systems, architectures of new urban rail transit green flexible power supply system are respectively proposed based on power electronics technologies. On the one hand, clean energy can be fully absorbed. On the other hand, energy utilization rate and the power supply quality can be improved through bidirectional converters, cophase power supply and other technologies, ultimately achieving the goal of energy saving and carbon reduction
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Research and Application of 5G and WiFi6 Technology in Subway BAS

XUE Chunyang, CHEN Bingqiu, YOU Lijing, JI Weijie

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The traditional networking schemes of building automation System are mainly redundant fieldbus and industrial Ethernet schemes, both of which require laying a large number of communication cables, and the data transmission speed and distance are limited to some extent. With the popularization and application of 5G and WiFi6 wireless communication technologies, after studying 5G and WiFi6 wireless communication technologies, a BAS redundant wireless communication scheme based on 5G and WiFi6 is proposed through comparison and analysis with traditional networking schemes. Compared with the traditional BAS networking scheme, this scheme greatly enhances the stability, reliability, expansibility, maintainability and real-time data of THE BAS system, optimizes the construction drawing design, avoids the laying of a large number of communication cables, and reduces the related materials and labor costs. This plan accords with the development of Chinese urban rail transit intelligent urban rail outline of the application of cloud computing, big data, Internet of things, 5G depth fusion passengers, emerging technologies such as facilities, equipment, environment and other new information to build safe, convenient, efficient, green, the economy of a new generation of Chinese wisdom of urban rail transit development strategy.
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Research on Intelligent Operation and Maintenance System of Urban Rail Transit Platform Gate

Li Bonan

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With the rapid development of subway construction, especially the promotion of unmanned mode operation, preventive maintenance, post-maintenance and comprehensive production maintenance are no longer in line with the development trend of high reliability and safety of smart subway. Therefore, this paper proposes a smart operation and maintenance system based on multi-parameter fusion prediction and evaluation under big data analysis according to the on-site operation situation of Zhengzhou metro, the difficulty of timely detection of faults encountered in daily operation and maintenance, and the vehicle delay caused by faults. Taking Zhengzhou metro as an example, the intelligent operation and maintenance system engineering prototype is established and the visual evaluation of equipment health status is carried out.
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Design and Implementation of Metro Network Control Center Based on gRPC Distributed Data Communication

zhongjianfeng, Meng Yukun, Wang Shisheng, Han Tian, Cai Yujing, Xuan Xiubin

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The metro network control center is based on the integrated monitoring system as the core,with data application system、operation execution system as collaborative management. Due to the large number of associated equipment systems、complex business,high requirements for real-time、concurrency、accuracy of massive data interaction,the data communication problem of metro network control center has always been a difficult problem. To solve this problem,based on the protocol buffer communication protocol,a metro network control center architecture based on gRPC distributed data communication is designed and implemented.The remote procedure call gRPC mechanism is a new communication mechanism in distributed systems and computer networks,under the network operation mode, by collecting a large number of equipment's data、business system's data,the standardized processing of platform data and high cohesion、loose coupling communication between business systems are realized,and the operation safety guarantee ability of urban rail transit is improved.
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Research on interconnection of AFC fare clearing system of urban rail transit in Guangdong-Hong Kong-Macao Greater Bay Area

LI Wu, Liang Qiang Sheng

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Abstract:

As the development of rail transit interconnection in domestic urban agglomerations has entered a critical period, the issue of rail transit AFC fare clearing system and interconnection under the background of cross-regional, multi-standard, and multi-operating entities has received extensive attention. This paper analyzes and studies the current situation of rail transit network operation, construction planning and priority development strategic requirements of rail transit interconnection in the Guangdong-Hong Kong-Macao Greater Bay Area, and analyzes the problems and challenges brought by the interconnection of rail transit in the Bay Area to the AFC fare clearing system management. Based on a comprehensive analysis and comparison of the AFC fare clearing interconnection modes of urban agglomerations, and on the basis of the successful experience of Guangfo urban rail transit AFC fare clearing system interconnection, the optimal realization mode of AFC fare clearing system interconnection of rail transit in the Bay Area is summarized. With the positioning of the rail transit bay area clearing and sorting center, it proposes the bay area rail transit AFC fare clearing system interconnection, one-ticket access management solution ideas and implementation steps, and points out the next technological realization direction of the Bay Area multi-network integration AFC fare clearing interconnection .
1
Design of Train Early Warning System Based on Laser in Depot

Shenhao

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Abstract:

Under the existing human-controlled management mechanism, since the maintenance and operation warehouses in the metro depot are semi-open areas, the entry and exit of personnel and the entry and exit of trains are frequent, there is a potential safety hazard of personnel-train conflicts. In this paper, through the analysis of track position setting of maintenance and operation warehouses and train operation scene in depot, a train early warning system design scheme based on laser is proposed. The system is based on laser ranging technology to measure different distance information during the movement of the train. After logical processing of computer technology, the system analyzes the different movement conditions of the train, and realizes the automatic warning of the train moving. At present, it has been piloted and applied in the Jinqiao Depot of Shanghai Metro Line 12. The results of the pilot show that the design scheme proposed in this paper is reasonable and feasible, which greatly reduces the safety risk of personnel-train conflicts.
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Research and Development of Urban Rail Transit Train Positioning System Based on PIS Network

huyongjian, maziyan, zhengjunfeng

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Abstract:

When the signal system fails, the dispatcher cannot know the position of the train. The existing backup mode and the telephone blocking method have the problem of low efficiency and certain safety hazards.The system provides speed information through the train speed sensor and acceleration sensor, continuously calculates the train displacement, and transmits it to the on-board positioning server through the PIS(Passenger Information System) network channel. Real-time train positioning. The system was verified on Hefei Railway Line 1. The results show that the system can achieve real-time train positioning under the condition of signal system failure of the entire line and individual trains. The average error between stations is less than 1m, the positioning error rate of the whole line is less than 1‰, and the one-way cumulative error distance of the whole line is less than 20m.
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Design Optimization and Innovation of Utility Tunnel with Urban Rail Transit

CHEN Hao

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Abstract:

Take the Metro Line 3 (phase 1 )utility tunnel project of Beijing as an example, discusses the advantages and problems of constructing utility tunnel with urban rail transit. According to the efficient and economical concept, the standard section design is optimized by reasonably section form and optimizing the installation and maintenance space. Combined with the construction conditions of urban rail transit and utility tunnel, innovative design of ventilation interval and escape manhole, rduce the number of vent and escape manhole on the ground. Make use of the shaft integrates the vent, hoisting hole, escape manhole and entrance,reduce the impact on urban landscape. Use the transverse passage structure space to construct ventilation room, substation.
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Field Study of Thermal Environment and Thermal Comfort of Xi"an Metro in Autumn and Winter

Gu Yaxiu, Huang Xingjie, Yu Liangshi, Cui Wei, Ma Zhuangzhuang, Huang Zemao, Qu Changjie, Gong Zexiang, Tan Zijing

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Abstract:

This study used a combination of thermal environment measurement and thermal comfort questionnaire to investigate the temperature variation of five representative stations and carriages of Xi'an Metro Line 2 in autumn and winter (September 2020 ~ February 2021). In winter, the average temperature at the entrance and the station hall of BEIKEZHAN station was 4.14℃ and 8.74℃, which did not meet the requirements of the Code for design of metro (GB 50157-2013). The comfort zone of the metro public area and carriages were plotted and analyzed : the temperature range of 80% satisfaction comfort zone in public area of Xi'an Metro Line 2 was from 15.7 to 22.8℃ during autumn, from 18.7 to 24.3℃ in the carriage, and from 12.3 to 16.1℃ in public area during winter. In this article, the thermal environment of metro station was evaluated by the combination of thermal sensation vote (TSV) and heat deficit rate (HDR). Compared with the results of the questionnaire, HDR was modified to obtain the thermal environment evaluation index suitable for Xi'an metro in winter. The study provided reliable basic data for the design and operation management of ventilation and air condition system in metro station, which was conducive to the construction of comfortable thermal environment for metro passengers.
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Research on Urban Rail Transit Service Quality Evaluation Considering Passenger Demand

HE Jing, XU Yuting

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Abstract:

The evaluation of urban rail transit service quality is a regular assessment work carried out by the industry supervisory department to monitor and evaluate the operation service level of rail transit. The traditional evaluation of urban rail transit service quality takes the form of comparing the overall scores of each line, with less exploration of the main perceptions and real needs of passengers. To improve the service quality of urban rail transit, an evaluation index system of urban rail transit service quality is constructed based on passengers' perceptions and demands and developed a comprehensive evaluation model based on SEM and Bayesian network. By evaluating the robust relationships among variables in the model through SEM and using Bayesian inference and diagnosis to assist in their decision making, the degree of influence of each variable on service quality can be more accurately revealed to achieve targeted optimization of service solutions and meet the multidimensional needs of passengers. Finally, take Kunming rail transit as an example. The results show that the magnitude of the influence of facility reliability, manual service, and travel safety on service quality is large (the path coefficients are 0.50, 0.39, and 0.38; the variation is 2.86%, 2.45%, and 2.20%, respectively). Meanwhile, the Deviance Information Criterion of the model proposed in this paper verifies the feasibility and applicability of the model. It can provide a reference for metro operators on how to improve service quality and attract more passenger flow.
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The exploration on implementation path of green construction of Urban Rail Transit under the "double carbon" goal

lulinhai, hanshuai, 孙捷城, 刘家海, 胡冰冰, 武朝军

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Abstract:

Based on the research on green construction of urban rail transit, this paper systematically combs the beneficial achievements of green construction of urban rail transit in terms of policy standard system，implementation route and green construction technology. Based on the investigation on the current situation of carbon emission of urban rail transit, the development direction of urban rail transit around carbon emission right is analyzed,the new requirements for the development of urban rail transit under the dual carbon goal are analyzed in detail from the perspectives of energy transformation, building materials production and energy efficiency. Based on the above two perspectives, the implementation path of green construction under the dual carbon goal is conceived in three aspects: policy and system construction, implementation route of green construction and low-carbon technology, which provides reference for the high-quality development of Urban Rail Transit under the dual carbon goal.
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TOD Path Exploration in the Chinese Context——Exampled with Shijiazhuang Case Study

YE Min, GAO Chang, WU Kehan, KANG Hao, WANG Sen, 11

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Abstract:

High-density development historically in central urban area has created good foundations for Chinese cities’ TOD development. However, a high-density midtown also faces challenges of citizens’ pursuit of high residential quality . It is an inevitable topic for TOD development in Chinese context to maintain the balance between high-density development and high-quality habitability innovatively. This paper takes Shijiazhuang as an example to carry out the Chinese TOD development patterns practice. Regional differentiation TOD strategy is adopted to guide an ecological urban land use，which focuses on central area compact development and suburb railway station area development. Land use optimization and Metro+slow traffic mode are also designed to encourage a public transport oriented green travel mode. People-oriented planning is adopted to allow a walking and bicycle friendly eco-city practice. As a typical provincial capital, Shijiazhuang’s TOD practice also accumulates experiences for similar cities.
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Urban development connecting stations and cities -- Tokyo Midtown Hibiya

ATSUSHI Omatsu, YASUTAKA Nishida, SHIGERU Yokoo, EMI Takada, KAINAN Fu, QIONGYI Huang, YUYING Shang, LIWEN Wang

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Abstract:

In Tokyo, TOD (Transit Oriented Development) development has been developed to expand the station space focused on the station and connect the entire town in detail. In this paper, we will take Tokyo Midtown Hibiya (hereinafter referred to as Midtown Hibiya) as a case study of TOD-type urban renewal. At Midtown Hibiya, we aimed to improve convenience and build a comfortable network by connecting to a subway station out of the developed region. In addition, problems along with the city development, such as improving public spaces for pedestrians and creating lively bases, are hopefully solved by urban renewal. Developers can make highly flexible plan proposals, and also need to make developments that contribute to the public. Midtown Hibiya use various cooperation methods for cross domain development through such urban plan mechanism. It is possible to utilize the technical experience of society capital to form high quality public space, thus promoting urban prosperity.S
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Review of Adaptability Evaluation for Transit-oriented Development of Passenger Transportation Hub

DAI Xiaoqing, KONG Wentao, ZHU Canghui, ZHAN Guohui, Li Penglin

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Abstract:

Passenger transportation hubs and surrounding areas have become one of the main carriers of the transit-oriented development in our country. Carrying out the adaptability evaluation before the development of the passenger transportation hub area can optimize the allocation of limited development resources, and make the overall planning for the massive passenger transportation hubs to be developed. This paper summarizes the related policies and adaptability evaluation of the TOD in passenger transportation hub areas, and points out that the following conclusions: adaptability evaluation should be based on the whole life cycle of the passenger transportation hub area development and the optimization of the overall functions of the hub, region and city, and adopts scientific index system and method, so as to promote the coordinated development of the hub, surrounding areas and the city, and to optimize the utilization of land and space.
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The Future Space Making: TODs and Space Syntax

Yang Tao

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Abstract:

The TODs, the kind of highly-intensified development area, have relatively complex spatial configurations, rich functions, and humanized spatial service radii. In this way, they will theoretically establish a new route of generating the future urban spatial forms. This article reviews the relevant concepts of the TODs and related typical diagrams, and attempts to analyze the spatial patterns and meanings of the TODs from the perspective of space syntax. Three spatial morphological questions are therefore proposed to distinguish TOD as a simple traffic node or an active place center, as a hyperlink tunnel across space or a fine-grained transformation of multi-layer folded spaces, and as an experiential collection of random individual attraction points or a collective representation of a fascinating complex spatial structure. These more or less illustrate certain scenes of real TODs. The space syntax provides a quantitative tool for thinking, verifying and describing these complex and provocative construction processes of the TODs from the perspectives of physical space composition, traffic travel pattern, social function combination, and human behavior perception, to pursue the spatial value overflow generated by the TODs, and to optimize the spatial experience within the TODs themselves. This article argues that space syntax will provide a good tool for making the spatial dynamics of the TODs.
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Paris Region on Rail and Its Inspirations: Coordination between Rail Transit Construction and Regional Spatial Development

liujian, zhouyixao, tanzongbo

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Abstract:

Urban transportation has always been closely interrelated with urban space. In the modern time, as urban development kept going, turning cities into metropoles and megalopolises, the role of transportation became more and more significant, in particular that of mass rail transit. In consequence, the interaction between transportation construction and spatial development called due concerns from the academia and the society. In order to find out the keys to promoting the coordination between the two aspects to support the sustainable development of metropoles and megalopolises, a case study on Paris Region is conducted based on literature, documents and observations. Dividing the evolution of Paris metropolitan area into three phases in line with the process of urbanization, the paper reviews the interaction between transportation construction and spatial development in a chronological way and summarizes the mechanisms and factors facilitating the coordination between them. It concludes that the empirical experience of Paris Region proves that broad social consensus, unified policy framework, effective planning coordination, and systematic management and governance are the key to promoting the coordination between transportation construction and spatial development, which can serve as useful reference for the planning and development of China’s metropolitan and megalopolitan areas in the era of New Urbanization.
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Shrinking Planning Methods and Mechanism under TOD Perspective: Interpretation of Location Optimization Plan in Japan

ZHANG Wanli, LIU Quan, LAI Yani

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Abstract:

Shrinking city is one of the hot topics of urban planning research. In recent years, Japan has developed the location optimization planning with the main idea of transforming from an expanding city to a compact city to meet the shrinking needs. Under the perspective of TOD, this planning systematically gives transit oriented shrinking methods. Especially in the shrunk area, location optimization planning puts forward clear countermeasures, include three aspects: the first is the land shrinking planning of non TOD area without rail transit support; the second is the transfer of FAR and facilities to the station area; the third is the feasible transformation from the shrinking area to the non-constructive land. This method can be understood as “Transit Oriented Shrinkage”. Through case studies, the efficient practice of location optimization planning for shrinking needs three aspects of system guarantee: coordination mechanism, incentive policy and declaration system. On this basis, this paper gives reference and thinking.
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Research and Prospect about Track Vibration Reduction Measures in Qingdao Subway

Lu Ruiquan

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Abstract:

In order to suppress the influence of vibration and noise on sensitive points along the line, various types of track vibration reduction measures are adopted in subway. However, the vibration reduction effect of track vibration reduction measures under hard rock geological conditions in Qingdao and other cities is still uncertain. The vibration reduction effects of three typical track vibration reduction measures under rock geological conditions are analyzed, the vibration reduction effects of compression vibration absorber fastener, elastic pad floating slab and steel spring floating slab respectively is 8.1dB, 12dB and 17dB. The vibration reduction effect about track-slab hybrid system, damping track bed and multi-grade vibration attenuation general precast track bed are also researched in this paper, the vibration reduction effects of above three new track damping structure types respectively is 18.2dB, 6-8dB and 10.4-17.1dB. Research results can provide reference for the follow-up subway construction in Qingdao and other cities.
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Research on the Design of Metro Station Combined with Property Development

Yu yumei

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Abstract:

Sorting out the space resources available for metro development, summarizing the ways of combining stations with properties, studying various typical cases, and pointing out that the design of metro stations combined with property development mainly includes two dimensions: one is to take the Metro station as the core, fully tap the space resources for property development inside and outside the station; the other is to effectively establish the spatial connection between the Metro station and the property development. Summarize the main characteristics of various types of metro stations combined with property development design. It expounds the value embodiment, design principles and layout rules of metro stations combined with property development. Analyze the impact of the construction sequence on the combination scheme, and refine the key points in humanized design, fire protection design, and flood control design. Suggestions on introducing a pre-planning and post-assessment mechanism, and establishing a systematic technical standard and specification.
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Research on e-CNY Application Mode in Urban Rail Transit

Zhou shi-shuang, Liang jing, Wang huan, Zhen yong-feng

Abstract: (181) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

According to the application specifications of e-CNY software wallet and hardware wallet and combined with the industrial characteristics of urban rail transit, this paper systematically analyzes the application scenarios, application schemes and application characteristics of software wallet direct payment, password free payment, cashier payment, hardware wallet value payment and quasi-account payment in the field of urban rail transit, and analyzes the advantages and disadvantages of various application modes in combination with practical application experience. This paper summarizes the optimal application scenarios and schemes of software wallet and hardware wallet, and puts forward the architecture of e-CNY application system and the innovative application idea of "e-CNY + public transport card" dual application. This paper looks forward to the mainstream application mode and promotion trend of digital RMB in the field of urban rail transit, so as to provide reference for the rapid promotion of e-CNY application in the field of urban rail transit, provide reference for promoting the intelligent development of passenger service.
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Correlation study on convergence parameters of point cloud cross-section in 3D laser scanning tunnel

HeZiyu, 罗桂军, 陈铁

Abstract: (155) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

Based on the tunnel point cloud data obtained by the mobile 3D laser scanning technology, point cloud preprocessing, section extraction and noisy point filtering were carried out, and finally the extraction of measured tunnel ring axial diameter and ellipse fitting were carried out to obtain the numerical and graphic results of horizontal axial diameter, ovality and other ellipse fitting results. From the perspective of geometric morphology, the mathematical relationship and correlation between ovality and ellipse fitting result parameters, such as horizontal transverse diameter and design deviation, ellipse circumference, ellipse axis mean-difference, were statistically analyzed and studied, and the automatic filtering method of long and short axis length outliers obtained by ellipse fitting of measured point cloud of tunnel ring was explored. The results show that there is a strong linear correlation between ovality and horizontal transverse diameter. Ellipse axis mean-difference D (the difference between the major axis plus the minor axis of the ellipse and twice the diameter of the theoretical circle) and the difference between the circumference of the ellipse and the theoretical circumference d has the constraint relation of the formula (11) in this paper, which can be used as the filtering basis for the long and short axis length outliers in the ellipse fitting of tunnel ring deformation.
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Comparative analysis of different energy storage systems of tram

Fan Xiaoyun, Pan Wenhai, Xue Chuan

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Abstract:

In order to improve the operation and management level of the energy storage tram projects, optimize the design of subsequent new projects and reduce the life cycle cost, this paper takes the vehicle energy storage system of Guangzhou Haizhu test section, Guangzhou Huangpu line 1 and Sanya tram project as the research object, combines with the design characteristics of their power supply system, analyzes the key technical principles, energy storage and consumption parameters, operation and maintenance difficulties, service life and costs. Among them, super capacitor system and battery capacitor system have certain advantages in equipment reliability; in terms of maintainability, all three systems have maintenance difficulties; battery capacitor systems have a higher degree of attenuation. Overall, improving the capacity of single energy storage system and the reliability of hybrid power supply system, simplifying the power supply system and carrying out intensive design will be the development direction of energy storage tram project in the future.
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Research on the Complex Network and Emergency Site Selection of Tianjin Rail Transit

wangbaoshun

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Abstract:

Tianjin has gradually formed a network operation mode of rail transit, but the emergency management of each line is relatively independent and poorly coordinated, resulting in low efficiency of emergency resource utilization and delayed emergency response. In this paper, a complex network model based on 11 Tianjin rail transit lines is established, the statistical characteristics are analyzed, and the vulnerability of station failure is studied. On the basis of considering the vulnerable sites to be protected, a site selection model for emergency facility centers suitable for the networked operation of Tianjin rail transit was established, a total of 26 emergency facility centers were determined, and their coverage was clarified. The results of site selection can improve the emergency efficiency of future networked operation. The analysis process is applicable to other rail transit networks.
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Research on Equipment Intelligent Operation and Maintenance System of Urban Rail Transit Based on Cloud-Edge-Terminal Frame

XU Yuming, LI Jiajing, ZHANG Ning, SHI Xianming, LIU Liping, HU Zuhan

Abstract: (129) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

The demand of equipment intelligent operation and maintenance is urgent under the background of urban rail transit network operation. This paper proposes an equipment intelligent operation and maintenance system of urban rail transit based on cloud-edge-terminal frame. The system uses the cloud-edge collaboration technology and some functions of cloud center are transferred to edge to realize the rapid response and effective application for terminal data by combining the advantages of cloud computing technology and edge computing technology. The system integrates equipment monitoring platform, equipment health management platform, equipment intelligent analysis platform, emergency command platform and expert system. It has the functions of equipment status online monitoring, equipment health evaluation, fault intelligent diagnosis, fault prediction, intelligent analysis and emergency command adjustment. The system can reduce the equipment failure rate and improve the efficiency of equipment operation and maintenance and ensure the safe operation of rail transit network. It has reference significance for improving the level of equipment intelligent operation and maintenance in urban rail transit.
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Zero on Site Testing of LTE-M Wireless Communication System based on Software Defined Radio

lanmeng

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Abstract:

LTE-M is used for the integrated bearing of urban rail transit in China. It’s necessary to carry out experimental testing and analysis of LTE-M on transmission characteristics and system stability. Testing along real-world rail lines is time-consuming and costly due to equipment costs and licensing restrictions. It’s important to develop a zero-on-site testing，which comprises simulation tools and testing procedures for carrying out open tests with clear operational rules and simple certification of test results. This paper combines hardware and software platforms to truly reproduce the end-to-end services and scenarios of urban rail transit infrastructure in the laboratory, and presents the zero on site testing scheme and test results of LTE-M wireless communication system, effectively demonstrating the feasibility of zero on site testing.
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Carbon emission analysis of rail transit station based on LCA

qian sheng ze

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Abstract:

As one of the largest carbon emitters, the construction industry accounts for about 25% of the world's total CO2 emissions each year. The building and operation phases are the most emitting phases in the whole life cycle of a building, so it is important to study the carbon emission of this part. This paper takes a rail transit station as a case study, decomposes the building stage, establishes the carbon emission calculation model of unit process, then analyzes the energy consumption of operation stage, and finally integrates to get the carbon emission calculation model of the whole project. Through the case study, it is found that the carbon emission of steel in the building stage accounts for 50.84% of the total material carbon emission; the largest share of diesel in the mechanical carbon emission is 70.62%; while the carbon emission of waste disposal in the personnel carbon emission reaches 78%, and the largest share of ventilation and air conditioning system in the station operation stage is 48.2%. According to the calculation results, energy saving and emission reduction measures are given in terms of machinery use, construction methods, energy sources and operation methods.
1
Review of Traction Power Supply Catenary and Reflux Safety in Urban Rail Transit

Yang Xiaofeng, Zheng Trillion Q.

Abstract: (203) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

Safe power supply is essential to guarantee the operation of urban rail transit. In this paper, a comprehensive review is carried out on the safe power supply technologies including catenary voltage fluctuation, rail potential and stray current mitigation. Considering the source of catenary voltage fluctuation is train regenerative braking energy, this paper firstly summarizes the research status of various regenerative braking energy utilization technologies. Then, the paper analysis the generation mechanism of rail potential and stray current, reviews and discusses the research status of rail potential and stray current mitigation technologies. On this basis, the key issues of safe power supply technology for urban rail transit are also pointed out, which will provide practical basis for industry application of future safe power supply technology.
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Design and Research on intelligent security system of fully automatic driving vehicle base

LIU Ying dong, YANG Fan

Abstract: (142) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

With the rapid development of intelligent control technology and wireless communication technology and the increasing maturity of the pilot of fully automatic subway line, the construction of fully automatic subway line has become the preferred scheme for new rail transit lines in various cities. Under this background, the full automation of main line has been gradually extended to vehicle base, resulting in great changes in the original safety management mode of vehicle base, For the new safety management risks, risk response measures and management efficiency improvement of the vehicle base, the design ideas shall be adjusted and matched with the functional requirements of the fully automated vehicle base. In order to study the design characteristics and innovation of the security system of the vehicle base of the fully automatic driving line, taking the security system design of the Wuqing depot of Chengdu rail transit line 9 as an example, through the design of the security measures at the boundary between the fully automatic driving area and the manned driving area, the perimeter of the whole depot, the key prevention and control points in the depot and the intelligent design of the security platform, Achieve effective division of functional zones, facilitate operation and management, avoid mutual interference between manned and unmanned operations, improve the intelligent level of security system in the section ^[1], and meet the needs of operation efficiency of fully automatic driving vehicle base.
1
Study on Setting Spacing of Suburban Railway Parking Line

lijunzhe

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Abstract:

Abstract The setting of suburban railway parking lines has a great impact on project cost and later operation. Different design specifications require different spacing of parking lines, which is not conducive to the planning and design of suburban railway. This paper first sorts out and analyzes the provisions on the spacing of parking lines in each design specification, and then obtains the key parameters affecting the spacing of parking lines by studying the basic principles, processes and time of rail transit fault rescue. Finally, the setting distance of urban ( suburban ) railway parking lines is calculated, and the recommended value of the setting distance of parking lines is proposed.
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Research on information Security Defense technology of Subway Signal System

zhangfengxia

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With the extensive application of new networking technologies such as Self-driving technology, urban rail cloud technology and interconnection in urban rail transit, a large number of internal and external interfaces of the signal system are increased, which brings malicious attacks to the system network environment from both inside and outside. As the "brain" of subway, information security of signal system is particularly important. By analyzing the overall network architecture of the signal system, the active and passive defense system of the information network security of the signal system is proposed in view of the hidden dangers and protection status of the information network security of the signal system. The passive defense model based on hierarchical protection is established by combining the existing active defense and passive defense technologies. And put forward the active defense model from three dimensions of security technology, security policy and security management, which can fully guarantee the information network security of signal system.
1
The Design and Construction of Continuous Through Girder Bridge with Composite U-Shape Section for Rail Transit

ZHU Hong-xin

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Abstract:

A prestressed concrete continuous beam bridge with composite section which combining U-shape section with box section is first constructed in No.17 rail transit line in Shanghai. In order to increase the applicable span of through girder with U-shape section to meet the requirements of large span bridges, a continuous through girder with brand-new section which is composed of upper U-shape section and lower box section is introduced. The mechanical properties of the girder is analysed by finite element method and its design procedure and standards are determined subsequently. The main span of the continuous through girder bridge with the composite section is 70 meters. This newly-built bridge is segmental concrete bridge constructed by free cantilever technique and incremental launching of precast segments which shortens the construction period, reduces the impact on environment, guarantees the quality of segments and make distinguished financial gains. Monitoring the stress changes in construction period and the dead load test on completed segmental bridge has been done effectively and through which the excellence of design and construction of the bridge as well as its safety is verified.
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Resilience evaluation and failure recovery strategy of metro network considering bus connection scenario

崔欣, Lu Qing-Chang, 徐标, 李静

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Bus connection is usually used to evacuate stranded passengers in case of metro disruptions. In view of the shortcomings of the existing metro network resilience indicator based on network topology efficiency, the network topology efficiency index is improved. This paper considers the impact of bus connection on passenger travel after metro station accidents, and puts forward the network efficiency accessibility index to measure the network performance. Based on the network efficiency accessibility index, a resilience evaluation model is constructed. The relationship between different repair strategies and network performance is discussed, and an optimal repair strategy aiming at maximizing resilience is proposed. Taking Shanghai metro network as an example, this paper studies the impact of bus connection on network performance and the optimal repair strategy under multi-stations failure scenario. The results show that bus connection under sudden failure can reduce the loss of network performance and improve the resilience of metro network. When the repair time of each failure station is different, the cumulative loss of network performance under the repair sequence based on resilience evaluation is lower than that under the repair sequence based on vulnerability evaluation. In the bus connection scenario, priority should be given to repairing stations with large passenger flow, sparse lines around the station, great impact after failure and short repair time, which will help to reduce the loss of network performance.
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Study on the system vulnerability of urban rail transit PPP project

Feng Yahong, Ma Huiyuan, Liu Ruihua

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On the basis of defining the concept of vulnerability of urban rail transit PPP project and analyzing its formation mechanism, through a large number of relevant cases and literature, multiple factors affecting the vulnerability of urban rail transit PPP project are identified. The system dynamic model is constructed from three dimensions of sensitivity, adaptability and exposure, and the causal relationship among various influencing factors was analyzed qualitatively and quantitatively. Then a practical case is selected to verify the applicability of the model, the constants in the model are simulated and analyzed to identify the key factors affecting the vulnerability of urban rail transit PPP projects. The simulation results show that the communication effectiveness of personnel, the reasonableness of franchise agreement and the economic strength of social capital have a significant impact on the vulnerability of the project, and these three factors should be focused in the project.
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Study on the Deformation Control of Metro Station Deep Excavation Adjacent to Viaduct Pile Foundation

wangxinjie

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Abstract:

Xiepu Road station of Shanghai metro line 14 under-crosses an approach of Yangpu Bridge, Finite element software Midas GTS was used to establish the three-dimensional model that considering the interactions among soil, supporting structure and piles to simulate the construction process of the deep excavation, and then to analyze the influence of deep excavation under different controlling measures on the deformation of the viaduct pile foundation. The numerical simulation values were compared with the actual monitoring data which demonstrated that parting and dividing foundation pit, reducing the bracing spacing, setting waterproof curtain for N-Jet method, could meet the deformation control index of the viaduct pile foundation and ensure the safe operation of the viaduct.
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Study of Vibration Influence of Metro in Small curve radius Track on Buildings with Different Foundation Forms

XIA Zanou, SHI Jin, ZHANG Qi

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Abstract:

The dynamic model of vehicle-track coupling vibration in Small curve radius track is established. The calculated reaction force of the coupler is used as the excitation source, and the finite element model of tunnel-stratum-building under the action of metro is established. The reliability of the model is verified by measuring the vibration response data of tunnel wall in curved track during actual train operation. The basic form of building finite element model is changed and the influence degree of the vibration response of the building by adopting the four basic forms of the building that is short of shallow foundation, short pile foundation, long pile foundation and raft foundation is compared and analyzed. Research indicates: With floors increase, the building lateral vibration decreases firstly and then increases, while the vertical vibration increases floor by floor; The vibration of the building increases in the medium and high frequency components (> 20 Hz), while the low frequency components decrease; In general, vertical vibration is greater than lateral vibration and the column vibration is greater than the floor vibration; The descending order of vibration levels of the four working conditions is as follows: raft foundation> shallow foundation> short pile foundation> long pile foundation, while the order of lateral vibration order from large to small is as follows: shallow foundation> short pile foundation> long pile foundation> raft foundation; In general, long pile foundation is the most favorable for reducing acceleration vibration level.
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Improved Design Measures and Model Tests for Stray Current Protection of Assembled Track

WU Lujing, Chen Peng, Xu Sixi, Zhang Huili

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At present, the isolation layer material of the prefabricated slab track of domestic rail transit adopts the geotextile scheme in the prefabricated slab track of the high-speed railway. The selection and setting of the isolation layer material do not consider the stray current protection problem under the DC traction system, resulting in Part of the stray current leaks. Aiming at this problem, this paper proposes a new scheme of using tetrahydroxy complex ester spray-type insulation material under the track plate of the prefabricated track structure to replace the traditional geotextile insulation material. In this paper, the insulation performance of the material is tested by designing the corresponding indoor model test scheme. The model test results show that when tetrahydroxy complex ester is used as the insulation material under the plate, the insulation performance of the track structure is greatly improved compared with that of the geotextile as the insulation material, which can better improve the stray current protection ability under the DC traction system. The research results have a good reference significance for the protection design of the stray current of the urban rail transit prefabricated track in the future.
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Research on Optimal Allocation of the Subway's Emergency Reserve Point under Uncertain Conditions

HEJING, zhushuangkai, 任晔

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In order to improve the subway's ability to prevent and deal with emergencies, the optimal allocation of the subway's emergency supplies reserve under uncertain conditions is explored. This thesis considers the uncertainty of the emergency material reserve point as well as the condition that the demand-point rescue is with the limitation of the time window, aims at minimizing the total cost of emergency logistics and minimizing the rescue time, a site-path model of subway emergency reserve points is established based on the relevant opportunity planning theory，and applies the genetic algorithm to solve the model. The calculation example verifies the effectiveness and robustness in solving the uncertainty of emergency material reserve points and the time window restriction of demand points , reducing the possibility of falling into the local optimum, and then providing information for the location decision of subway emergency material reserve points.
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Discussion on controlling target and limit of viaduct noise in urban rail transit

Tan wen, yuquanyu

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This paper points out that at present, the noise control standard of viaduct in China is still blank, and its control indexes and limits refer to the "Environmental quality standard for noise" (GB3096). Therefore, this paper analyzes in detail the deficiencies of the noise control indexes and limits of day-time and night-time equivalent sound level in the current "Environmental quality standard for noise" (GB3096) in the noise control of viaduct. Based on the comparative analysis of other noise standards at home and abroad, this paper puts forward supplementary suggestions on the equivalent A-level noise control index and limit value of train passing period according to the noise impact characteristics of domestic viaduct, which increases the impact of morning and evening period and background noise increment, which can be used as a reference for noise control of viaduct.
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Research and Application of Vibration and Noise Treatment Technology for Underground Line in Urban Rail Transit

SHE Cai-gao, YANG Xiu-ren, ZHANG Bo-lin, GAO Liang, WU Jian-zhong, LIU Peng-hui, WU Xiang-yang, QU Cun

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With the increasing number of urban rail transit operation lines in major cities, the problem of vibration and noise caused by underground lines in urban rail transit operation are increasingly significant. In this paper, the vibration and noise complaint of sensitive points of Nanjing Metro Line is taken as the research object, and the vibration and noise treatment issues for underground line of urban rail transit are researched. Firstly, the status of rail transit area in the section corresponding to the complaint sensitive point and the residents in the sensitive point community are investigated. Then the environmental vibration, indoor vibration and secondary structure noise of sensitive points are tested and analyzed. According to the investigation and the exceeding standard, preliminary treatment measures are formulated. The spatial coupling theoretical simulation analysis model of vehicle-track-tunnel-soil-building for sensitive points is established and used to demonstrate the effectiveness of treatment measures. On this basis, the treatment work of vibration and noise is carried out, and the treatment effect is tested and evaluated. Through a large number of test data and home visit, the effectiveness of the treatment measures is verified quantitatively and qualitatively. This research has important reference significance for the scientific treatment of vibration and noise problems of urban rail transit in the future.
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Analysis on the influence of the internal and external pressure variation on structural safety of a subway section tunnel

Huang Chunhun, REN Lei, Li Chunjian

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Affected by extreme weather, the water level of the artificial lake rises rapidly, and the subway shield tunnel passing through the artificial lake subsides. In order to study the reasons for the subsidence deformation of the subway shield tunnel structure, and to evaluate the structural safety of the shield tunnel after the deformation. The deformation of the shield tunnel is analyzed by analyzing the monitoring data on site, using the load structure model to check the strength of the shield tunnel, and the stratum structure model simulating the loading and unloading conditions above the shield tunnel. The calculation results show that the rising water level of the artificial lake is the main reason for the deformation and sinking of the shield tunnel. After the deformation occurs, the bearing capacity and crack width of the tunnel structure meet the design and specification requirements of the shield tunnel, and the shield tunnel structure itself is still safe.
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Research on the Protective Effect of Zinc Strip in AC Power Supply Metro on AC Interference of Buried Pipelines

Chen Xia, Ya Shangsong, Li Yi, He Zhixin, Long Yiren, Cao Xiaobin

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With the rapid development of China's economy, China's urban subway network is more and more widely distributed. Due to its own limitations, the traditional DC power supply system is increasingly unable to meet the existing and future needs. Therefore, the AC power supply system will be used in some urban express lines, such as Guangzhou Metro 22, which will open in 2021. The power supply system produces AC interference to adjacent buried pipelines through electromagnetic coupling of space and resistive coupling of the earth. In engineering, the method of winding zinc tape is often used to suppress the AC interference of pipelines. In this paper, the simulation model of an AC metro line, oil and gas pipeline and zinc strip is built, the electromagnetic induction voltage, ground coupling potential and coating withstand voltage before and after laying zinc strip are calculated, the prevention effect of zinc strip on AC interference is studied, and the operation life under AC interference is analyzed by calculating the corrosion of zinc strip. The study found that the corrosion ability of AC stray current is relatively weak, and the corrosion amount of AC interference to the zinc strip is only 0.3% per year; The AC current density of the pipeline after the zinc tape is laid can be reduced by 87.2%, which shows the zinc tape has a significant suppression effect on the AC interference of the pipeline.
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Optimization analysis of BAS control scheme for ventilation and air-conditioning in subway stations

Hu Zhenya, YANG Zhuo, LI Shaoguang, Tan Qinghui, Wang Xu, LI Xiaofeng

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The air-conditioning control scheme has a significant impact on the system consumption energy. Relevant studies show that the wind-water linkage control system is a more energy-saving and efficient control scheme than BAS system. At present, a large number of domestic subway stations adopts conventional BAS system, and its transformation into wind-water linkage control requires a lot of cost investment. Without changing hardware configuration, whether the conventional BAS system can improve the energy-saving rate through the optimization of operation strategy and achieve good energy-saving effect is worth studying. The operation of the BAS systems in many domestic subway lines and stations was investigated, analyzed the common conditions in actual operation, and proposed an optimization scheme for the control strategy. A typical Nanning subway station was selected to verify the BAS optimization scheme. Compared and analyzed the operating effects of the BAS optimization scheme and the original BAS scheme. The research results show that the energy saving rate of conventional BAS system after certain optimization and improvement is significantly improved, and good energy-saving effects can be achieved. The research provides an effective path for the operation optimization of conventional BAS system in subway stations.
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Energy use index of ventilation and air-conditioning system for subway stations in various climate regions in China

SU Ziyi, LI Xiaofeng

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This paper establishes the constraint value (CV) and leading value (LV) for the ventilation and air-conditioning (VAC) energy consumption of subway stations with platform screen door (PSD) system in various cities in China. Firstly, extensive investigation was conducted on number of passengers, train departure density, station temperature, device efficiency and other information to determine the values of input parameters for the studied cases. Then VAC energy consumption was simulated for a total of 3096 cases (for 43 cities under 36 types of service conditions and 2 kinds of operation management levels). Simulation results show that the CV and LV of annual VAC energy consumption are 0.176-0.859 million kWh and 0.175-0.529 million kWh, respectively. Secondly, linear regression analysis was used to investigate the relationship between CV and LV of annual VAC energy consumption and local climatic conditions. It was found that the R2 of VAC energy consumption and annual average wet-bulb temperature are 0.951 and 0.949 for CV and LV, respectively. Finally, for each city, multiple linear regression analysis was carried out on CV and LV of VAC energy consumption and the three service condition parameters, including number of passengers, train departure density and tunnel length. Based on this, fitting coefficients can be proposed for each city, providing a convenient and effective tool for operators and managers to evaluate VAC energy consumption of subway stations.
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Statistical Analysis of Urban Rail Transit Operation in theWorld in 2021: A Review

Li Yawei

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The article summarizes the statistics for 2021 on operation of urban rail transit systems in the world, which are classified into metro, light rail and tram systems in line with the widely accepted international standards. The statistics show that 541 cities in 76 countries or regions worldwide have hosted urban transit systems by the end of 2021, with the total length reaching 36, 854.20 kilometers, among which, the metro system accounts for 51.4%, the light rail 8.9% and the tram 39.7%. Urban rail transit systems have been built and put into operation in 50 Chinese cities and the total length in operation has reached 9192.62 kilometers by the end of 2021. The ridership of metro declines significantly affected by COVID-19 in 2020, which totals 39.67 billion trips in 137 cities of 46 countries and regions worldwide with an average of 5, 400 trips per day, including 19.502 billion passengers in China. It is found that China ranks the first in the world in terms of the size and ridership of its urban rail transit system networks. Statistics on fully automatic operation show that there are more than 2,380 kilometers of lines with GoA4 operating level, of which 587.57 kilometers in China. Exploring a set of fully automatic operation modes suitable for China"s national conditions will further promote the development of multi-regime rail transport and provide powerful support for building China"s strength in transportation.
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Study on the Green and Low-carbon Development of Urban Rail Transit

SHI Zhongheng, DING Shukui

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At present, with China''s integration of "carbon peaking and carbon neutralization" into the overall layout of ecological civilization construction, the Communist Party of China Central Committee and the State Council unveiled a guiding document on the country''s work to achieve carbon peaking and carbon neutrality goals under the new development philosophy and released an action plan for carbon dioxide peaking before 2030 successively. The documents set a timetable and road map for China to achieve the goal of "carbon peak and carbon neutralization", and require key industries to respond and implement. Urban rail transit is a high-capacity public transport infrastructure and the backbone transportation mode for cities to guide and carry low-carbon travel. Meanwhile, the urban mass transit in China is in the stage of rapid development, and its energy consumption and carbon emission reduction pressure is increasing with the overall scale maintaining sustained growth. Based on the analysis of the development status and advantages of urban rail transit in China, this paper puts forward the objectives, key tasks and guarantee measures of green and low-carbon development of urban rail transit, which provides reference for urban rail transit to achieve "carbon peak and carbon neutralization" by speeding up green and low-carbon transformation, taping the potential of energy conservation and emission reduction, improving the level of energy efficiency, and promoting the urban rail industry.
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Overview of urban rail transit lines in mainland China in 2021

Hou Xiufang, Mei Jianping, Zuo Chao

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.By the end of 2021,there were 9192.62km urban rail transit in 50 cities put into operation. In 2021, 5 new cities were added, and the total length of new lines was 1222.92km. The new line3 involved 35 cities and 62 lines(section).The number of new routes and the number of cities involved were all record highs.
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Exploration on the new mode of urban rail operation

XIE Zhengguang, WEI Yun

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Quality and benefit become the working emphasis of the new development paradigm, with the extension and densified urban rail network, and improved quality requirements of People"s travel in China. However, the existing traditional operation mode is failed in the new scene, and also has seriously restricted the high-quality development of urban rail. A new operation mode for urban rail network system is urgently in need. Firstly, the new the operational requirements and trends for urban rail in China are summarized in this paper. On the basis of research above, a new networked operation mode is constructed. A profound study for the operation vocational work and management system is made. At last, eight significant tasks during the period of the 14^th Five-Year Plan are conducted, based on the industrial pain points and newly built operation mode. This paper aims to provide some notions and research direction for the transformation and upgrading of urban rail operation mode.
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Application and Practice on Recharge of High Pressure Confined Aquifer in Deep Excavation of Hangzhou Metro

fengwei

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The effective treatment of confined aquifer is an important factor which determines the safety of excavation. By taking the example of the project of airport ventilation shaft of Hangzhou Metro Line 1 Phase III, this paper optimizes the design parameters of excavation, and adopts the treatment measure of pumping and recharging confined aquifer, effectively solving the technical difficulties including no drainage conditions nearby the excavation engineering and the adverse conditions of sensitive surrounding location. The monitoring results indicate that each monitoring data of excavation is under control. The treatment measure of pumping and recharging confined aquifer can not only reduces the engineering cost, but also effectively protects the surrounding environment, providing a certain reference value and guiding significance to the construction of deep excavation in the similar engineering conditions.
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Upward Floating Law and Control Measures of Shield Segments in Water Rich and Confined Strata

TAN Zhangtao, LIU Dongfang, SUN Cuihua, LI Fanhua, CHEN Yu

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During the subway shield construction, the problem of shield segment lifting is very common. In some cases, it may even lead to the deviation of tunnel axis that exceeds the limit and hence affects the design and planning of the entire line. This paper summarizes and analyzes the phenomenon and characteristics of shield segment lifting in China, pointing out the important role of confined water in inducing segment lifting. Based on investigating a shield tunnel in Beijing metro line 17, we accomplished theoretical analyses and numerical simulations of shield tunneling in a water-rich stratum with confined water. The results show that, if only the effects of grouting buoyancy and stratum rebound are considered, it is difficult to explain the large lifting of segments in this project. When the effect of confined water is further taken into account, a reasonable explanation is obtained. Shortening the coagulating time of synchronous grouting and supplementing secondary grouting are measures specific for dealing with grouting buoyancy, while radial grouting around the tunnel can reduce the segment lifting induced by stratum rebound as well as confined water.
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Turn-off Strategy of SCR Based Switch Unit in Zero-Resistance Converter System

Chen Maolu, Yang Xiaofeng, Zheng Trillion Q, Zhao Zhijun, Xia Xue, Gu Jingda

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Zero-resistance converter system (ZRCS) is a power-electronic-based stray current mitigation measure in urban rail transit. As one of key devices, switch unit (SU) transfers thousands of amps traction current from the running rails to return cable. In view of the challenges of loss and reliability for the IGBT-based SU, this paper employs silicon controlled rectifier switch unit (SCR-SU) in ZRCS. However, SCR-SU faces the turning off problem. Based on analysis of SCR-SU turn-off mechanism, a SCR-SU turn-off strategy with negative resistance converter from system aspect is proposed. Simulation and experimental results indicate that the ZRCS with SCR-SU can realize SCR-SU’s turning off by adopting the proposed SCR-SU turn-off strategy. With its normal operation, ZRCS with SCR-SU can effectively reduce the stray current in urban rail transit system, and has a good application prospect.
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Optimal Distribution of Switch Unit in Zero-resistance Converter System

Yang Xiaofeng

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Zero-resistance converter system(ZRCS) transfers the rail current from returning point to return cable, then mitigate the rail potential and stray current of urban rail transit from the source. As one of the key devices, switch unit(SU) influence the position of returning equi-point in ZRCS, and the number and distribution of SUs affect the distribution of rail potential and stray current directly. In the actual train operation, the train current under traction and braking conditions are much larger than that under constant speed conditions, resulting in larger rail potential correspondingly. By changing the SUs distribution, rail potential of this part can be reduced and the comprehensive mitigation performance of ZRCS can be improved. Therefore, based on analysis of the role of SU, a method for the SUs distribution optimization is proposed. By comparing the mitigation performance under different SUs distribution, the optimal SUs distribution is obtained. Simulation results indicate that the proposed optimization method can improve the mitigation performance of ZRCS.
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The invalidation analysis and new protection schemes of stray current to Urban Rail Transit

ZHANG Kaibo

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Considering the invalidation against stray current in urban rail transit, the source of stray current and transmission path of stray current by conventional protection methods are analyzed. To reduce the source of stray current, a new rail insulation protective sleeve method is proposed，enlarge and keep effective of the insulation creepage at rail fastener in its life-cycle；to cut off the path of stray current transmission, a new scheme are proposed to effectively block the unexpected transmission path，including use double insulation joint and directional return current methods, etc . The total leakage of stray current shall be effectively reduced to realize the sustainable development of urban rail transit.
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Economic Benefits of Different Land Development Modes of Urban Rail Transit Stations Peripheral Areas

TONG Ruiyong, MAO Baohua, XU Qi, WEI Runbin, HUANG Junsheng, XIAO Zhongsheng

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This paper constructed economic benefits calculation models of different land development modes of urban rail transit stations peripheral areas as the perspective of the government. The modes included urban rail transit enterprises leading and real estate enterprises leading. The operating profits calculations of rail transit lines, land development benefits calculations and government benefits calculations were carried out. Finally, two land development scenarios of one-time income and continuous income were analyzed by the example of an urban rail transit line. The research results show that in the scenario of one-time income, operating losses can be covered through development gains and part of taxes with the construction of potential lands of 109,600 square meters under the mode of urban rail transit enterprise leading. The average annual government benefits reach 240 million yuan. In the scenario of continuous income, the average annual government benefits under the mode of urban rail transit enterprise leading are greater than that under another mode regardless of the operating periods. The losses can be almost covered no matter which period under the mode of urban rail transit enterprise leading. Only 23.65%, 20.75% and 16.74% of the tax amount will be used as subsidies in each period.
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Comparative study on design schemes of bidirectional converters in the subway power supply System

SHI DAN

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Aimed at three schemes of configurations of bidirectional converters and rectifiers, which are used in the power supply system for metro, this paper comparatively analyzed the selection principle of rated power of equipment, cooperative control strategies, the harmonic influence of injection points at the main substation. It is suggested that the bidirectional converter should work as a matter of priority to reduce the negative effect of low-order harmonic caused by the 12-pulse rectifier. This paper summarized the configuration features of short circuit protection both on ac side and dc side. The undervoltage lockout can be set on the ac side to increase the sensitivity. The bidirectional power flow should be considered on the dc side.
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The Design Thinking and Creative Practice of Green Elevated Station

Zhang Xiaolin, Zhang Yan

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This paper introduces the research background of green building, the problems of domestic rail transit elevated station. On the basis of the preliminary research, analysis and summary, under the guidance of the performance goal of green building, and in accordance with the substantive spirit of the three concepts of "humanities, science and technology, green", the design scheme of Zhangguozhuang green elevated station was put forward. and the design scheme is systematically introduced. In the implementation stage, due to the limitations of the construction period and technical ability, the green technology of the preliminary plan had not been fully implemented, and some schemes had also been simplified and adjusted. and the implementation plan and the final effect are explained and analyzed. This is the first attempt of green elevated stations in the urban rail field in China, which helps to improve the green level of future engineering projects.
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Analysis on planning and design theory of improving land use efficiency of overlying property development in Shenzhen metro vehicle base

weiming, 朱斌, luojianhai, dingyang

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As the key node of urban rail transit, vehicle base has the value of overlying property development. Make full use of the roof platform and surrounding space of the vehicle base to develop the overlying property, so as to make it the only way for the sound development of the subway and the city. Based on the mutual input conditions of the "upper building property" and "lower building" of the vehicle base for their respective use functions, space allocation and traffic flow lines, the coupling elements are refined, and the design of the upper building of the vehicle base based on the intensive utilization of land resources is studied. In view of the current situation of urban rail vehicle bases at home and abroad, this paper combs and innovates the traditional architecture and process design system, and makes a scientific and detailed analysis on the characteristics of upper buildings, so as to obtain the optimal dimensional data of buildings, so as to improve the utilization of land resources on the upper cover of vehicle bases, so as to achieve win-win economic and social benefits.
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Research on the Evaluation of the Humanized Design of the Space Under the Cover of Metro Vehicle Base

guobin, gaohe

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After the development of the superstructure of the metro vehicle base, it can effectively increase the land utilization rate of the vehicle base and create considerable economic benefits. However, if it is not handled properly, it will greatly reduce the quality of the working environment under the superstructure. In response to this problem, this research aims to optimize the humanized design of the space under the cover of the metro vehicle base, and evaluate the humanized design of the space under the cover using grounded theory and IPA analysis. First, the grounded theory analysis is used to obtain the evaluation indicators of the humanized design of the undercover space, which is divided into two main categories, and the evaluation index system for the humanized design of the undercover space is constructed accordingly. Then, the IPA analysis method is used to analyze the grounded theory The importance and satisfaction of the various evaluation indicators obtained are evaluated. Finally, based on the above analysis, a humanized design optimization strategy for the space under the subway vehicle base cover is proposed, in order to provide a more humane working environment for the workers under the cover, and to provide a more humane working environment for the track Provide guarantee for long-term safe operation of traffic.
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Operation Mode Optimization of the Network Control Center under the Condition of Network Operation in Suzhou Rail Transit

JIANG Zhibin, TANG Yan, WANG Zhiyong, LIU Xiaofei

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The construction of the network control center is the inevitable choice after the in-depth development of urban rail transit network operation. It is the core organization for network operation coordination, information interconnection, and emergency linkage. Based on the experience of domestic typical urban rail transit network operation and management, and the operational requirements of Suzhou Rail Transit such as the severity of operational safety, the diversity of equipment system, the complexity of line network structure, the diversity of operation organization, the fluctuation of network passenger flow, the heterogeneity of travel characteristic, and the multiplicity of traffic connection, the operation functions of Suzhou Rail Transit NCC (Network Control Center) are optimized. Finally, taking the network passenger flow analysis as an example, the business process and optimization suggestions are put forward, which could provide support for the delicacy management and control of network passenger flow.
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Concept Discrimination and Selection Research of Urban Rail Transit Station Super-Peak Coefficient

WANG Jing, WANG Jun, LIU Jianfeng, YANG Guanhua, DING Yi

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The station super-peak coefficient is one of the key indicators reflecting the characteristics of the station's peak passenger flow, and it is an important basis for the design of urban rail transit facilities. Discriminating the concept of the super-peak factor, the super-peak factor of a station should be the ratio of the maximum 20-minute passenger flow hourly equivalent during the peak hour of the station to the passenger flow entering and leaving the station during the peak hour. Then this paper comprehensively analyzes the super-peak coefficient of each station of Beijing urban rail transit, and puts forward the main influencing factors of the super-peak coefficient of rail transit stations. The results show that about 74% of urban rail transit stations have super peak coefficients in the recommended range of 1.1-1.4, and another 26% of stations have super peak coefficients in the range of 1.0-1.1, which is lower than the recommended value. The nature of the land around the station, the station entry and exit passenger volume during peak hours, and the passenger flow control measures (metro current limit) of the station all have an impact on the value of the super peak coefficient of the station. It is more likely that the over-peak coefficient of employment oriented station takes a larger value; the station with small passenger flow during peak hours tends to have a large over-peak coefficient, while the super-peak coefficient of ultra large peak passenger flow scale station generally does not exceed 1.2. In addition, the current limit of rail transit stations will reduce its super peak coefficient.
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Intelligent Optimal Control Method of Metro Multi-Converter Based on Goose Communication

duguifu

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At present, each converter of traction substation in the metro line operates independently, which cannot realize real-time information interaction, precise adjustment and coordinated control, which increases the loss of the system network and reduces the system security performance. In order to solve this problem, the intelligent optimal control method of metro multi-converter based on Goose communication is proposed. The hierarchical control strategy for multi-converter is built based on the Goose communication network. Taking the minimum network loss and the minimum of the rail potential amplitude as the goals, a dual-objective optimization control algorithm for multi-converters based on the NSGA-II algorithm is proposed. A dynamic power flow simulation platform of the traction power supply system in metro line is built for simulation verification. The results show that the intelligent optimal control method of multi-converter based on Goose can realize the dynamic management and coordinated control of multi-converter, which will reduce the network loss and rail potential. Compared with the traditional optimization control without communication, the intelligent optimal control method of multi-converter can optimize the output characteristics of converters in real time, and realize the goal of energy-saving and safe operation.
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Influence of the Insulation State of Shield Doors on the Reflux Safety Parameters in Urban Rail Transit

YU Haipeng, BAO Ming, LIU Shuai, ZHANG Dongliang

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The reflux safety of DC traction power supply system in urban rail transit has gradually become one of the current research focuses. The shield doors that are equipotential with the running rails will affect the distribution of reflux safety parameters due to the unsatisfactory insulation. Aiming at the influence of the insulation status of the shield doors on the reflux safety parameters, a simulation model of multi-train dynamic power flow is established, and simulations are carried out based on the data of Wuxi Metro Line 2. The results show that the weak insulation status of the shield doors will result in a significant increase in the reflux safety parameters, threatening the safety of equipment and personnel. When the insulation of the two shield doors is weak, a leakage loop of stray current will be formed, which will aggravate the abnormal increase of the reflux safety parameters. The lower the insulation resistance of the shield doors, the lower the amplitude of the rail potential, but the higher the stray current. In addition, when the insulation of multiple shield doors is weak, the reflux safety parameters will increase sharply, posing a serious threat to the safety of equipment, passengers and staff.
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Study on Planning Scheme of High Speed Maglev route in the Guangdong-Hong Kong-Macau Greater Bay Area

qin qing

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Based on technical and systematic features of high speed maglev and the status quo of society, economy and transportation in the Guangdong-Hong Kong-Macau Greater Bay Area and the Guangzhou-Shenzhen-Hong Kong corridor, this article analyses the necessity, function positioning and traffic volume of Guangzhou-Shenzhen-Hong Kong Maglev, probes into the status quo and city planning of Guangzhou, Shenzhen and Hong Kong, assesses different proposals of transit corridors and station distribution of Guangzhou-Shenzhen-Hong Kong Maglev. We preliminarily put forward technical standards and a plan of corridor and station distribution, which would optimize the technical and economic advantages of the Maglev system.
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Research on the Reserved Project Design for the Cover Development of Beijing URT Vehicle Base

ZHENG Xin

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The reserved project for the cover development of vehicle base affects the safety of the vehicle base operation as well as the feasibility of the cover development project. Based on the cover development project of Beijing URT vehicle base , this paper discusses the types, design concepts, design contents of reserved project for the vehicle base cover development. Combined with the cover development project examples of vehicle base in Beijing, reserved design is discussed in five dimensions which are site planning, development building, structural load, equipment pipeline and implementation conditions, analyze the specific implementation strategies, put forward the design points in different stages and conditions, and provide references and suggestions for the subsequent design of the reserved project for Beijing vehicle base cover development project.
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Study on the Integrated Joint Construction Model of Urban Traffic Elevation Project

FANGYINGLI

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Based on the concept of integration of transportation engineering facilities, a typical viaduct railway integration co-construction scheme is proposed based on the case. The innovation and advantage of co-construction mode are systematically analyzed, and the key content of engineering design scheme is discussed. It is pointed out that the viaduct railway integration co-construction mode innovatively integrates three-dimensional traffic mode; It has the characteristics of occupying no space and separating from the urban space. The advantage of this scheme is to reduce the separation of urban space, and it has the characteristics of short construction period, low risk, more economical investment, easy to achieve maintenance, management, environmental control, disaster prevention, and so on. It can realize the maximum benefit and efficiency of land resources. The scheme has a demonstration and reference value for improving the degree of integration of major transportation infrastructure and promoting the coordinated development of central city and new town in metropolitan area.
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Simulation Research on Coupling Vibration of Suspended Monorail Vehicle-Bridge System under Wind

LI Jing, LIU Shi-wen, ZHU Bing, ZHANG Zhen, ZHANG Zi-yi

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Abstract:

The main girder of suspension monorail transit system is usually steel box girder with lower opening. The structure stiffness is small, and the vehicle is prone to lateral swing under the action of wind, thus affecting the structure safety and ride comfort.SSIn this paper, the 30m span simply supported section of a tourist special line project is taken as the engineering background to conduct the dynamic response simulation analysis under different wind speed and different speed.SSFinite element software was used to build the bridge model, and multi-system dynamics software was used to build the vehicle and track models. The vehicle, track system and bridge system were co-simulated as a complete system.SSThe static three-component force coefficient and wind load of the bridge and train were calculated by CFD software, and the static wind force was superimposed into the model to form the coupling vibration model of the windmill bridge.SSThe results show that the transverse and vertical dynamic displacements of the bridge increase with the increase of wind speed, and the change of the transverse displacement is more obvious, but the change of the dynamic displacement is not obvious with the increase of vehicle speed.SSThe vehicle ride decreases with the increase of wind speed and speed, and the vehicle lateral ride is more sensitive to the average wind.SSIn all working conditions, the maximum values of the vertical and lateral Sperling coefficients of the vehicle were 2.49 and 2.62, respectively, indicating that the running vehicle had good smoothness.SSThe co-simulation method of coupling dynamic analysis of windmill bridge based on general finite element software and multi-body dynamics software is reliable and efficient.SSThe research results can provide reference for wind resistance design and application of suspension monorail transit system. S
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Research and Application on Rail Fracture Monitoring Based on Ultrasonic Guided Wave Technology

liu Jianli, Geng Ming, Li Bo

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China's modern rail transit system in recent years in the intelligent, high-speed and information integration technology have made new breakthroughs, rail line equipment as the basic conditions of running operation, rail plays an indispensable leading role in the operation system, so to ensure the safe operation of urban rail transit, rail injury and damage monitoring and maintenance is very important. In this paper, based on ultrasonic wave guide technology for modern rail transit rail for real-time fracture monitoring, research shows that the rail real-time monitoring system can detect incomplete fracture and through breakage, and accurate prediction of medium and long distance monitoring, cost reduction and quality improvement. In order to build a modern rail transit comprehensive monitoring system, and in-depth development of ultrasonic detection methods in the application of modern rail transit, for the protection of rail transit operation safety has important practical significance.
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Research on Integration Mode and Selection Decision-making Method of Suburban Railway and other Rail Transit

JI Yannan, ZHAO Shuyi, YANG Lin, LI Dewei

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At present, China is vigorously promoting the integration of rail transit in urban agglomeration and metropolitan area, and promoting the development of "four networks integration" of rail transit. However, most of the existing literatures still focus on the qualitative analysis of the implementation methods of "four networks integration", and lack of systematic and quantitative research on how to realize "four networks integration". In order to provide ideas for better integration in the process of rail transit planning, this paper takes the integration mode of suburban railway and other rail transit as the research object and how to select the integration mode as the research purpose, puts forward the integration mode and the two-stage decision-making method for selecting the technology integration mode according to the technical conditions, passenger flow characteristics, economic benefits and other factors, and takes Xining Qinghai Lake Chaka (Chahanno) railway as an example to make a case analysis. It is concluded that the two-stage decision-making method is feasible, and the rail through operation mode is adopted for the integration of Xining Qinghai Lake Chaka (Chahanno) railway and Xining-Ge' ermu Section of Qinghai-Tibet railway.
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Classification of Urban Rail Transit Transfer Stations Based on Multi-factor Clustering

LI Qing, DONG Xiaochun, SHEN Yu, ZHENG Xuanchuan, SONG Weitao

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In order to solve the problem of the lack or inaccuracy of the transfer station classification standard, this paper analyzes the influencing factors of the transfer station classification from three dimensions of land use, location, and passenger flow, and proposes a calculation method for classification indicators. Combined with the K-Means clustering algorithm, a multi-factor classification method of transfer station is constructed. and the transfer station of Nanjing Metro was applied to carry out case analysis. The results show that：compared with the single factor (land only, location only, and passenger flow only) clustering method, the multi-factor clustering method has obvious advantages in classification uniformity, clustering distance, and actual classification effect. Combining the classification results, it is proposed that the transfer stations of Nanjing Metro should be classified into five categories: integrated hub type, public center type, residential and life type, industrial office type and peripheral connection type, and analyzed the threshold characteristics and value recommendations of the different elements of the transfer station. The research results of this paper can provide important reference for subway transfer station planning and design in the future.
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Research of New Generation Urban Rail Rransit Automation Systems Fusion Platform based on Cloud-Edge CooperationWang Jianwen Zhao Wenlong Huang Guohui

wangjianwen

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Cloud computing have been widely used in the integration and fusion of urban rail transit automation system. The existing centralized cloud platform construction has some issues, such as high network load, longer user-perceived latency, and large scale of data center. This paper optimizes and builds a four-layer overall architecture of a new generation fusion platform with edge layer, foundation layer, platform layer and application layer. Through the cooperation of edge-cloud computing, the real-time performance is improved, the scale of DC is controlled, and conducive to the development of intelligent applications. This paper put forward a step-by-step manner and typical application examples.
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Research on the Design Scheme of Fire-fighting Wireless Communication System in Metro Interchange Station

WANG Peng

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How to build a Metro fire-fighting wireless communication system under the new standard is the key research content of the urban transit industry. Taking the interchange station of Xi"an Metro Line 8 as the starting point and combining the current status, this paper proposes a design scheme of fire-fighting wireless communication system suitable for different types of interchange stations responded to the ePDT series of specifications and standards officially released by the Ministry of Emergency management. By establishing a complex scene model, the coverage capability and base station demodulation capability of the design scheme are quantitatively analyzed. The research shows that by upgrading the existing base station and introducing the analog optical fiber repeater system, when the edge field strength of the system is set to be higher than -90dBm and the base station has no more than 9 repeater remote units, it can meet the requirements of interchange stations and tunnel section coverage requirements. The research results can provide references for the engineering design and network optimization of the urban transit fire-fighting wireless communication system under the new situation.
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Prediction of Short-term Inbound Passenger Flow of Urban Rail Transit

Ouyang Xin

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Abstract:

In view of the existing urban rail transit short-term traffic forecasting a single model may predict instability problems, this paper puts forward a kind of based on singular spectrum analysis (SSA), and by combining support vector regression (SVR) forecasting model. The combined model uses singular spectrum analysis (SSA) to decompose and reconstruct the original time series passenger flow data of rail transit, and sort the reconstructed time series by singular values from large to small to obtain the main information containing the original time series data. The reconstructed sequence of the components uses the reconstructed time series as the input of the support vector regression model (SVR), and finally the short-term inbound passenger flow prediction of each station is carried out. This paper collects the urban rail transit passenger flow data of the entire network in Beijing in November 2015, and validates and compares the proposed short-term passenger flow prediction model. The results show that the prediction accuracy of the combined model proposed in this paper is higher and more stable than ARIMA model, SVR model, CNN-LSTM model and T-GCN model, which has a certain practical significance.
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Temporal and Spatial Changes in Advantageous Areas of Urban Rail Transit in Hangzhou

wufang, zhuyue, hujun, zhuwei, huxiaojun

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Taking the Hangzhou subway station network as an example, using complex network and spatial pattern analysis methods to study the temporal and spatial characteristics of urban rail transit advantageous areas. It is of great significance for understanding the distribution of subway passenger flow and the evolution of urban patterns. The results show that: ①The passenger flow of subway stations has a significant positive correlation with the centrality index of subway stations, and the station centrality index can partially predict the passenger flow of stations. ②With the expansion of the subway network, the stations with centrality advantages are not static, and the stations with centrality advantages often have the characteristics of large subway passenger flow. ③In general, there is a trend of low in east, west, south and north, and high in the central area. The western area of the city (Hangzhou West Railway Station and the Future Science and Technology City) will become an important development area of Hangzhou. The site network at each stage presents significant high-value agglomeration characteristics in space. For the betweenness, the high-value agglomeration area is always closely connected with two areas (the intersection of Fengqi Road and Yan'an Road, and the East Railway Station area). For the closeness, the intersection of Fengqi Road and Yan'an Road is the source point of the high-value cluster area, and it shows a trend of continuous expansion in all directions. The above-mentioned area is highly consistent with the current station area with the highest passenger flow of Hangzhou Metro.
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Research on Urban Development Strategy Guided by TOD Coupling Mechanism under Complex Network -- A Case Study of Beijing

Fan Minghao, 洪于亮, 戴冀峰, 许丹丹

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In recent years, TOD is regarded by many planning decision-makers as an important starting point to solve the problem of supply and demand in large cities, and takes it as the planning basis for urban development strategy research. However, in the application practice of localization, the impact of TOD on space guidance, value orientation, technological change and planning paradigm needs to be further clarified. Taking Beijing as an example, this paper identifies the spatial coupling state of urban central system and rail transit at the level of urban zoning through complex network feature measurement, points out the existing planning and construction problems of dual system, and puts forward the multi-dimensional coupling strategy of dual system under TOD mode, in order to cultivate the transformation of TOD to urban development policy and promote the healthy and sustainable development of the city.
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Analysis of the Influence of Soil Structure on Stray Current Distribution in Urban Rail Transit

ZHOU Qi, LIN Sheng, ZOU Quande, LI Yuda

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The harm of stray current is becoming more and more prominent with the rapid development of urban rail transit. The distribution of stray current is affected by many factors, such as train operating conditions, length of power supply section, rail transition resistance and soil structure. Studying the influencing factors of stray current is the basis of preventing stray current. In order to study the influence of soil structure on the distribution of stray current in urban rail transit, a stray current simulation model with multi-layer soil structure was constructed in this paper. Based on the simulation model, the effects of resistivity and soil thickness in uniform soil and layered soil on stray current distribution were analyzed. The simulation results show that the soil structure will affect the current distribution in the drainage network, auxiliary drainage and the earth, but has little effect on the rail potential and the total stray current distribution along the line. In addition, in the layered soil structure, the smaller the thickness of the first layer of soil or the greater the resistivity, the less stray current flows to the earth.
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Study on optimization of smoke control strategy for access tunnels of Zhengzhou metro line 10

XIA Sanxian, WANG Yan, MENG Xin, ZHANG Xiaowei, HU Fan, XIA Yanling

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Jet fans are often used to increase longitudinal ventilation velocity in the smoke control system of subway access tunnels. The cost of power distribution system of jet fan is much higher than that of jet fan in the smoke control system of subway access tunnels. Tunnel ventilation velocity and smoke exhaust effect for five smoke control strategies for the subway access tunnel of Zhengzhou metro line 10 were investigated by using the FDS numerical simulation method. The economic analysis of five smoke control strategies have also been carried out. Results of numerical simulation show that tunnel ventilation velocity below 2m/s can meet the requirements of smoke control in the access tunnel which is a non-passenger section tunnel. Four 60m3/s emergency fans can basically meet the needs of tunnel smoke exhaust for the subway access tunnels in the smoke control system without jet fans at access tunnel portals. The smoke control system without jet fans at access tunnel portals can prevent smoke threaten the safety of station operation. The short smoke back-layering length will not affect the safe evacuation of metro train drivers. If the installation conditions permit, a group of jet fans are recommended to be installed at the station side of the subway access tunnels, which can improve the tunnel ventilation velocity and smoke exhaust effect. in order to solve the problem of smoke retention in station tunnel, the two emergency fans at the subway station side of access tunnels is proposed to be started 30 seconds later than the other fans.
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Research on the application of occluding pile water-stop curtain in PBA undercut tunnel

niejinchi

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The long construction period and the heavy precipitation of the underground excavation project in urban rail transit have a significant impact on protecting urban groundwater resources. Therefore, the cities strictly control the underground water reduction in subway projects by formulating related policies. The waterproof curtain of plastic concrete and reinforced concrete occlusive pile has the advantages of high strength, strong anti-seepage and controllable cost. It has long-term application value in subway waterproof and drainage engineering. This work focuses on water-proof curtain test project of occlusion pile in an underground tunnel in Beijing Metro. In order to further reduce groundwater discharge and effectively protect groundwater resources, the technical feasibility of water-proof curtain of plastic concrete and reinforced concrete occlusion pile under the limited space of the PBA undercut tunnel was analysed and verified. Moreover, the sealing effect of occlusive pile curtain is verified by means of analytical method, numerical simulation and pumping test. The results indicate that the permeability coefficient of occlusal pile is 1.88×10-6cm/s, in agreement with the design requirements. The water-proofing effect of occlusive pile is obvious, and the stable water inflow is reduced from 2129 m3/d to 6.8 m3/d. The verticality of most piles could achieve the control value. There is no distinct difference in the water level elevation of external observation well and no water seepage in the excavation. The research results verify that the technical scheme and construction technology meet the criterion of the project construction, which can provide reference for the design and construction of similar projects in the future.
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Research on the Influence of the Station-area Built Environment on the Rail Transit Ridership——A Case Study of Hefei

YAN Ran, ZHANG Chun, ZHENG Hao

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In order to quantify the nonlinear influences of the built environment and accessibility on rail transit ridership, based on Hefei rail transit station ridership, a gradient boosting decision tree model is applied to investigate the nonlinear influences and threshold effect of the built environment on ridership by considering the accessibility of the rail transit network and the walkability of the station area. The results show that on the basis of controlling accessibility, the station-area built environment is still the most important factor affecting the ridership of rail transit station, with an impact of about 63%-65%. The built environment and accessibility variables all exhibit non-linear effects and threshold effects on rail transit ridership. High pedestrian accessibility, high density and mixed land use have a decisive influence on the ridership of rail station.
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Rail Potential Hardware Dynamic Emulator ConsideringTrain Operating Condition

Wang Shuanghui, Yang Xiaofeng, Wang Huikang, Zheng Trillion Q.

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Abstract:

In view of the field verification challenges of rail potential and stray current mitigation measures, the rail potential hardware dynamic emulator (RPHDE) has received extensive attention in recent years. However, the existing RPHDEs generally consider the rail longitudinal resistance by ignoring the influence of train operation conditions and rail-to-earth resistance, so it cannot accurately reproduce the dynamic rail potential distribution along the line. Therefore, a novel RPHDE considering the train operating condition is proposed. This paper firstly analysis the influence of train operating conditions on rail potential with the DC traction power supply system model. Then based on dynamic characteristics analysis of the catenary, running rails and rail-to-earth resistance, the operation principles and mathematical model of proposed RPHDE are studied in detail. Moreover, the corresponding control strategies of RPHDE by considering the train operating condition is also proposed. Finally, the simulation and experimental results verify the correctness of the abovementioned theorical analysis and control strategies.
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Construction of BIM model for urban rail transit in operation and maintenance stage

Han Dezhi, Li Bo, Hua Fucai, Yang Liangyin, Zheng Guangliang

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Abstract:

Systematic solutions were proposed for the common problems of building information model (BIM), such as information missing, difficulty in data cleaning, and complex docking with existing systems in the operation and maintenance stage of urban rail transit projects.By investigating the application scenarios and business requirements in the operation and maintenance stage, the geometric accuracy, information depth and architecture, information classification and coding requirements of model units were established, and specific model construction and data collection methods were given;By establishing the mapping relationship between model classification code, design number and asset management code, the model can be integrated with database, comprehensive monitoring system and asset management system smoothly, the operation and maintenance platform can monitor the running status of the equipment and retrieve the work order and ledger information of the asset management system.Through the strict implementation of model technical requirements and coding requirements, the model that meets the operation and maintenance requirements of urban rail transit can be built.
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Study on The Influence of Section Occupancy Status on Interlocking System

zhaohaixin

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Abstract:

CBTC, a communication-based train control system, is widely used in urban rail transit, and become a new standard of urban rail transit signal system. Compared with previous signal systems, CBTC has a significant advantage of shorter train tracking interval, which is closely related to the way in which the signal system divides the track block. Physical extents being subdivided into several shorter logical extents makes the same physical segments accommodate more trains in operation. However, this leads to a new problem, the need to deal with two kinds of Section Occupancy status s which are from two different information sources. And this two information may be inconsistent under certain circumstances, which makes signal fail to close or the route fail to be unlocked, affecting the operation efficiency. In order to get a more reliable Section Occupancy status , this paper discusses the cause of the two block states information inconsistence from the failure occupation of the axle counter, the train positioning error, and the system time delay, analyses the approach and problems when dealing with block states in a specific scenario, puts forward adding the train across signal information or using the judgment strategy of instant occupation and delay clearing on the basis of block fusion, which not only ensures the safety and reliability of the signal system, but also improves the efficiency of train operation.
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Analysis of Seismic Capacity of Suspension Track Beam Y-shaped Pier Column

WEI Xing, MAOHONGLIN

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Abstract:

In order to study the seismic resistance of suspended track beams in the absence of vehicles, the suspension rail transit test line in Dayi County was used as the research object, the model was established using MIDAS/CIVIL and the response spectrum method was used to study different earthquake intensities (0.1, 0.15g, 0.2g, 0.3g, 0.4g) on Y-shaped steel piers and concrete piers. The results show that the lateral stiffness of the bridge is smaller;compared with lateral earthquakes, the Y-shaped pier column has a greater internal force response under the action of the bridge direction earthquake; when the seismic acceleration is greater than 0.1g, the 4th concrete pier column begins to crack; When the seismic acceleration is greater than or equal to 0.25g, the No. 3 concrete pier column begins to crack; in the seismic peak acceleration discussed, neither the Y-shaped steel pier nor the concrete pier column yields, but the bending moment of the concrete pier column grows faster. , There is a tendency to yield first.
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Study on the Characteristics and Optimization of Holiday Passenger Flow in Urban Rail Transit under COVID-19 Prevention and Control

GUANG ZHI RUI

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Abstract:

In order to meet the demands of regular COVID-19 prevention and control, urban rail is facing the contradiction between improving the attractiveness of passenger traffic to promote domestic demand and the risk of uncontrolled spread of the epidemic in large passenger flows at key stations. To deal with this problem, this paper conducts an in-depth analysis of the passenger flow of urban rail transportation in Beijing during holidays over the years, and summarizes the characteristics of passenger flow during holidays under regular epidemic prevention and control. By studying the interaction relationship between passenger flow and the influencing factors over the years, more than 40 influencing factors that play a role in this particular period were identified in 3 types. These influencing factors are analyzed one by one to extract main reasons for the low attractiveness: imprecise operation management, inconvenient passenger travel, and non-direct metro lines etc. In conclusion, based on the analysis of the characteristics and influencing factors of urban rail transit passenger flow, the operation optimization strategies are proposed: carrying out refined management, providing intelligent services, and promoting synergy and integration.
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Seismic Vulnerability Analysis of Continuous Rigid Frame Bridge Without Support

CHEN Liang, CHEN Yiming, GUO Min, LI Jianzhong

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Abstract:

The continuous rigid frame bridge without support is a new type of structure developed recently. It has been widely used in the rail transit structure of Guangzhou, Changsha, Fuzhou and other cities, but there is little research on the seismic performance of continuous rigid frame bridge without support. Based on the typical continuous rigid frame bridge without support, the paper analyzes the failure process and seismic damage risk of continuous rigid frame bridge without support under earthquake. On this basis, based on the seismic vulnerability analysis method, the typical seismic vulnerability curves of piers of continuous rigid frame bridge without support are given, and the seismic damage risk of continuous rigid frame bridge without support is discussed.
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Study on Determining Train Timetable of Equilibrium Interval Based on Virtual Coupling

ZHAOXINGDONG, wangwei, 赵, 赵

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Abstract:

This paper summarizes the influence of virtual coupling on transportation organization and the study of determining train timetable. Then, a train diagram of equilibrium interval based on virtual coupling is proposed. This paper puts forward the steps to determine the train timetable of equilibrium interval based on virtual coupling, and then the evaluation indexes of the train timetable are determined from the two aspects of service level and operation cost. This paper uses the analytic hierarchy process to evaluate different schemes. Finally, taking Beijing metro Line 19 as an example, this paper analyzes the effectiveness of the method to improve service level and reduce operation cost based on virtual coupling.
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Study on the Rationality of Setting Artificial Grounding Grid above the Roof of Underground Station Structure

CHEN Xia, HE Zhixin, ZHOU Dan, DENG Shu, YA Shangsong, WANG Wei

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Abstract:

In order to study the rationality and feasibility of setting artificial grounding grid above the top plate of underground station structure, firstly, the grounding structure of underground station is described, the grounding grid model of underground station is established by using CDEGS software, and the difference of power frequency grounding resistance between the grounding grid below the bottom plate of station structure and above the top plate of station structure is compared. The difference of resistance between them is 60% ~ 70%, The results show that the soil resistivity and soil thickness play an important role in the grounding resistance, and the grid size and conductor diameter of the grounding grid have little effect on the resistance. If 1 Ω is taken as the measurement index of grounding grid resistance value of underground station, in most cases, the grounding grid is set above the top plate of station structure, which can better limit the power frequency grounding resistance value within 1 Ω, and the calculation result of grounding resistance value is in the range of 0.7 Ω ~ 0.8 Ω as a whole. Finally, the safety indexes such as contact voltage and step voltage on the square surface of the grounding grid are studied. The results show that when a serious short-circuit grounding fault occurs, setting the grounding grid above the top plate of the station structure will not cause the contact voltage and step voltage above the surface to exceed the standard, and has a high safety factor, It is proved that it is feasible and reasonable to set up artificial grounding grid above the roof of underground station structure. The research results have high engineering practice reference significance and strong application value.
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ConsiderationsSandSSuggestionsSonStheSDevelopmentSofSRailSTransitSinSTypeSIISMetropolises

LIFANG, LIU Jianfeng

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In view of the existing problems in the rail transit planning approval and construction practice in the current urban population of Type II large cities with a population of between 1 million and 3 million, an in-depth analysis of the passenger flow demand and the socio-economic, social, economic, and social Passive catch-up and advance planning, system standards and laying methods are three major puzzles, objectively understand traffic needs, accurately grasp functional positioning, reasonably determine the level and scale of the network, choose appropriate laying methods and system standards, and diversified operation and organization models Several thoughts and suggestions have been put forward to provide useful suggestions for the long-term and healthy development of rail transit in Type II large cities with special urban land use patterns, high population agglomeration and serious traffic congestion.
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Study of internal force analysis and construction technology of long-span columnless arch structure of Jinan Metro Longao station

WANG Dan, LI Zhao, LIU Weilong, YUAN Man, NING Bo, MENG Fanming

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Abstract:

Columnless subway station has the characteristics of wide spatial vision, high passenger flow efficiency and beautiful appearance. It has been successfully applied in many cities. In order to study the mechanical characteristics and construction technology of long-span columnless arch subway station in hard rock stratum, based on Longao station of Jinan subway, two-dimensional finite difference numerical calculation was carried out. The results showed that: 1) the horizontal displacement and internal force of the supporting structure caused by foundation pit construction were small, and the safe construction of foundation pit can be ensured by multi-stage slope excavation and shotcrete anchor support; 2) The bending moment and axial force of the top plate of the columnless arch structure were large, and the middle plate was eccentrically tensioned, which was a weak link in the main structure, but it still has a large safety factor, and the whole structure is safe and reliable. The construction technology of long-span columnless arch station has been successfully applied in Jinan Metro Longao station, which can provide reference for similar projects.
1
Settlement control standard and control of shield tunneling under high speed railway subgrade Measures research

BAI Yangyang

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Abstract:

In order to study the settlement control measures and effects of the shield tunnel passing through the high-speed railway foundation from below, taking the phase III project of Xi'an Metro Line 1 - Shield Crossing Xulan high-speed railway section as the background, through the analysis of current specifications and similar cases of existing projects, combined with the current situation of existing ballastless track, determined the control standards for the tunnel to pass through the subgrade of the high-speed rail ballastless track from below, selected measures such as shield tunneling, reinforcement and auxiliary deformation control for the shield tunnel to pass through the high-speed railway foundation, according to the construction plan and the actual situation of the project, the criterion and threshold of the influence zone are theoretically analyzed, and then the zones affected by different railway subgrades are divided, and the implementation effect of the proposed construction plan is analyzed through the method of numerical simulation. The results show that the scheme of avoiding CFG piles and grouting reinforcement with sleeve valve pipe on the ground when the shield tunnel crosses the high-speed railway foundation can meet the engineering requirements. The maximum vertical displacement of the track bed is 4.716mm, and the maximum horizontal displacement is only 0.301mm; The maximum vertical displacement of the CFG pile is 11.93mm.
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Research on the Engineering Gauge of Changsha Maglev East Extension Line Connected to T3 Terminal

DAI Nengyun, DAI Wang, QIU Bing, DENG Juanhong, HOU Xikuai

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The Changsha Maglev East Extension Line connecting to the T3 terminal is the first maglev shield tunnel project in China and the longest maglev tunnel project in the world. In order to scientifically and reasonably formulate the section size of the tunnel project and ensure the safe and stable operation of the maglev train, an in-depth study was conducted on the gauge of the Changsha Maglev East Extension Line connecting to the T3 terminal.Referring to the "Standards of Metro Gauges" and considering the structural characteristics of maglev vehicles, several typical building gauges such as vehicle gauges, equipment gauges, shield tunnel construction gauges, open cut construction gauges, and underground station construction gauges have been studied，detailed structure gauge charts of typical sections are presented. Research shows that the use of a shield tunnel with an inner diameter of 6.1m can meet the train-tunnel dimension ratio and the safe and stable operation of maglev trains, and has certain economic efficiency.The Changsha Maglev East Extension Line connecting to the T3 terminal project has started construction,and the design of the building boundary is safe，economical and reasonable, which provides a reference for the subsequent construction of the maglev tunnel project.
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Construction technology of underwater receiving of shield machines in water-rich fine sand stratum

Ye Xinfeng, Zhang Ningzhong, Wu JingYi, Li Zhengdong, Gong Jieying, Liu Shangwei, Li Yanpeng

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Abstract:

Based on the shield tunnel construction interval in the south side of Qinghe station of Beijing Metro Line 19 project, the procedures, risks and control parameters of each stage of the underwater receiving of shield machines were analyzed and the corresponding risk control measures were obtained and successfully applied. The shield parameters and monitoring results indicated that: when the height of filled water is 0.5m~1m above the ground water level, water and sand spewing can be effectively controlled. During the receiving period, the earth pressure gradually decreased from 0.8~1.2bar of the 15th ring to 0bar, the synchronous grouting amount was appropriately increased to 1.25 times of the theoretical value, and the advance speed was 5.1mm/min. When shield approaching the 2nd ring of the retaining pile, the thrust increased from 9000kN to 20000kN, and during the grinding pile period, the thrust was between 9000kN and 14000kN, and the risk was controllable. The settlement mainly occurred in two stages including the stage of cutter head coming out of the tunnel and the stage of shield tail coming out of the tunnel. The settlement values were in the range of -0.9mm~-1.5mm and -4.0mm~-4.8mm respectively. The influence of shield tail coming out of the tunnel was greater than that of cutter head coming out the tunnel.
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Resilience Evaluation of Fully Automatic Operation System Based on Bayesian Network

WU NAI ZHE

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Abstract:

In order to further improve the safety level of the fully automated operation system, an evaluation method based on the Bayesian network model is provided for the resilience evaluation of automatic train operation system. According to the performance change curve before and after train failure, four kinds of system resilience capabilities are summarized. Based on these four resilience capabilities, the influencing factors of these four capabilities are explored, and the appropriate evaluation index is selected as the bottom nodes of Bayesian network. The appropriate membership formula is selected as the calculation method of conditional probability, the conditional probability table of Bayesian network is obtained, and the Bayesian network model of automatic train operation system is established to quantitatively evaluate the system resilience. At the same time, the sensitivity analysis of target nodes is carried out to explore. According to the results of sensitivity analysis, some suggestions are put forward to improve the resilience.
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Research on Timing and Scheme of Additional Procurement of Vehicles in Urban Rail Transit

FANG Xiaohong

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Abstract:

The procurement of urban rail transit vehicles must go through specific approval procedures, and the vehicle production cycle is long and the price is expensive. The vehicle purchase opportunity and scheme must be reasonably formulated based on the principle of saving cost and improving efficiency. This paper fully considers the necessity and urgency, approval procedures and procurement cycle, capacity adaptation and economic benefits of additional procurement of vehicles, puts forward the determination method of target year and working time of additional procurement of vehicles, defines the methods and matters needing attention for the calculation of the scale of additional vehicles and the additional procurement scheme design, and puts forward that the scheme can be established only after the checking calculation of parking and maintenance capacity of existing sections and yards. Finally, Taking Zhengzhou Rail Transit Line 1 as an example, the systematicness and integrity of the demonstration method are verified.
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Construction and Operation Analysis and planning suggestions of Xi'an Urban Rail Transit Circle Lines

LÜ Changming

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Abstract:

In order to clarify the planning concept and design idea of Xi'an urban rail transit circle lines， Combined with the development of urban spatial structure and the preparation process of line network planning，this paper takes Xi'an rail transit line 8 as an example to summarize the characteristics of circle lines planning conception, construction necessity, corridor selection, line scale, construction opportunity, passenger flow characteristics, operation organization and so on. As the only rail transit circle line in Xi'an rail transit network, line 8 is arranged between the second ring road and the third ring road in the main urban area, and it conforms to the urban land layout and connects multiple core clusters in the urban center. Line 8 also has the characteristics of large interchange passenger flow, small average haul distance, less imbalance of passenger flow in the upstream and downstream sections of the same section, and more balanced passenger flow section in peak hours， so a large route will be opened at the beginning, in the near future and in the long term for the whole line. The line has some difficulties, such as difficult location of depot, long entrance and exit line, poor line shape of turning section and great difficulty in implementation, the transfer station with no reserved transfer conditions needs to be reconstructed. Based on the research on the planning and design of line 8, this paper puts forward relevant suggestions on the planning concept, passenger flow research and connectivity for . urban rail transit circle lines.d.
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Application of Energy Storage Technology in Stationary Regenerative Braking Energy Absorption and Utilization System

YANG Zhongping, LIN Fei

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With the rapid development of energy storage component technology such as electric double layer capacitor, lithium-ion battery and flywheel, energy storage technology has been widely used in urban rail transit. Aiming at the stationary storage regenerative braking energy utilization system, firstly, the functions of the energy storage device are summarized; Then it introduces the current situation of energy storage technology in stationary energy storage system; Finally, the issues that need further research and development are analyzed from the perspective of system design and evaluation method of energy storage device, charge and discharge strategy and design of energy storage device.
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Research on Performance and Design Method of Seismic Isolation for Rail Transit Viaduct Based on Friction Pendulum Bearings

Hu Songsong, Chen Gong, Li Pandao

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Since the rail transit viaduct based on friction pendulum seismic isolation bearings tends to have a large displacement during earthquakes, thus making adjacent spans prone to potential collision due to the phase difference, it is necessary to explore how to reduce the relative displacement of beam ends while obtaining a high isolation rate, to avoid the collision of adjacent span structures. This paper, based on the viaduct on the Pinggu line of Beijing rail transit service, discusses the effects of seismic isolation design in different seismic peak acceleration areas and its economic advantages compared with ductile seismic design, derives the calculation formula of structural system period, and proposes the design method for width of expansion joint at beam ends. An analysis herein shows that, in the area of 0.2g and 0.3g peak acceleration, the isolation rate of piers remains almost the same and the seismic isolation design in the peak acceleration area demonstrates a convincing cost-effectiveness, and that the closer the structural system period of adjacent span systems are, the smaller the relative displacement is for beam ends.
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Comparative study on electric interlocking system between China and South Korea

DONG Chenwen, 李小帅, 马晓姣

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Compared with the traditional relay interface method, the all electronic execution unit has many advantages, such as flexible configuration, cost saving, space saving, easy commissioning and installation, and so on, and has become one of the development trends of computer interlocking system. The research progress of indigenous all electronic interlocking systems in China and South Korea is compared and analyzed from three aspects: system architecture, communication protocol and system test. Through comparison, it is found that all electronic interlocking system in South Korea mainly draws on the EULYNX standard framework of the European railway, which is mainly used in the railway trunk line, and all electronic interlocking system in China is currently used in urban rail transit lines and some field ends, and has not been officially carried out in the main railway line, so as to learn from the experience of South Korean. Both use safe and reliable measures to ensure the safety of the system in terms of system architecture and communication protocol, and finally verify the feasibility of the system through laboratory and engineering field tests.
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Risk analysis, prevention and control of urban rail transit operation system based on Bayesian network

LIU Yiwen, Zhu Lin, LIU Zhigang, Luo Huarong, Hang Hai

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This paper collects and analyzes 64 cases of urban rail transit operation risk incidents. Based on the analysis of the cause of the accident, 28 risk items are extracted and the accident cause chain is established; the Bayesian network is used to construct the risk interaction relationship of urban rail transit accidents.The influence intensity analysis and sensitivity analysis of the risk interaction network found that human and equipment factors are likely to cause other risks and even safety incidents in the system.Among them, the three risk items of the switch equipment failure of the signal system, the brake equipment failure of the vehicle system, and the information exchange lag have a greater impact on the stability of the entire safe operation system.Finally, risk prevention and control strategies are proposed from the four dimensions of human, machine, environment, and management, especially safety management countermeasures for key sensitive risks.
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Case Study on Integrated Development Planning and Implementation of Urban Railway Station Area at Home and Abroad

WANG Yanli, JIN Yunning, HAO Sicheng, GAO Tianshuang, LI Linbo, WU Bing

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The integrated development of urban rail stations and surrounding land is one of the keys to the coordinated development of the two, and it has a positive effect on urban economy and transportation. A summary and analysis of the domestic and foreign integrated development of the urban rail station area can better guide the integrated development of the rail station area in my country. From the perspective of property and urban economics, this paper divides the integrated development into two types: internal-and-external integrated development and up-and-down integrated development, and has made relevant definitions. Combined with the Japanese integrated development policy and Shibuya station data, Shanghai integrated development policy and Dapuqiao station area data, the planning and implementation of two integrated development types and their applicability in my country are analyzed. Finally, referring to more classic cases of integrated development, compare and analysis the implementation mechanism and characteristics of the integrated development of urban rail station areas at home and abroad, and the enlightenment for our country is given from the perspectives of policy and planning, The research results show that our country can adopt the mode of “government overall planning and market execution”; according to our country’s land ownership system, explore diversified land management modes such as “intensive exchange for use rights” and “integral transfer of use rights” , which are conducive to the strategy of cost sharing and revenue sharing; formulate supporting and detailed technical specifications; carry out three-dimensional, diversified, and integrated design.
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Study on Skip-stop Operation Organization Plan of Virtual Coupling Trains in Urban Rail Transit

baijiawei, zhangqi, lufang

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The development of virtual coupling technology offers the possibility to improve the traditional skip-stop operation organization in urban rail transit, which is expected to alleviate the problems of increased travel time of slow trains and loss of line passing capacity in the traditional operation organization. The paper analyzes the typical operation process under the virtual coupling technology and gives the formula for calculating the station interval time under the virtual grouping condition. The two strategies of skip-stop operation organization under virtual coupling technology whether to implement overtaking are proposed, and through the analysis of examples, the paper compares the effect of train operation under different organization modes. The results show that the skip-stop operation organization under the virtual coupling (implement overtaking) shortens the train tracking interval time and shortens the passenger travel time under certain passenger flow conditions; with the application of virtual coupling technology, the skip-stop operation implement overtaking further shortens the stopping time of slow train and the travel time of fast train compared with the one that doesn't implement overtaking.
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Research on automatic prediction of deformation of retaining structure in deep foundation pit construction based on BP artificial neural network

mengguowang, huangjingsong, liujialiang, ouqiang

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In the process of deep foundation pit construction, the horizontal displacement monitoring of the retaining structure is one of the important measures to ensure the construction safety, and the analysis and prediction of the deformation trend of the retaining structure are the most important. In this regard, this paper conducted a field investigation on the automatic monitoring equipment of the enclosure structure, and proposed a method of multi-step rolling prediction of the horizontal displacement of the enclosure structure combined with the BP artificial neural network model. The real monitoring data of the deep foundation pit construction enclosure structure of the Nanning Metro Line 5 station was taken as the training sample, three modes of learning were performed on the sample data. The first one was to compare the prediction results of different piles at the same time after learning; secondly, one was to compare the prediction results of the same pile at the same time after sample learning at different time intervals; the third was to compare the prediction results of the same pile after multi-step rolling prediction is achieved. The results show that the prediction errors of the three modes can meet the requirements. It provides a method with strong practicability and high credibility to realize the automatic prediction of the deformation of the enclosure structure.
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Research and realization of key technology of integrated navigation system for subway station inside and outside

WANG Xiaojun, ZHANG Wenqiang, LIU Siyuan, chejing

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With the increasing number of subway lines in Beijing, the service facilities in the station are gradually enriched, and the environment complexity in the station is increasing. At present, passengers in the station travel encounter the following problems, the station navigation is needed to improve the satisfaction of passengers travel: station transfer is complex: the subway station is more and more complex, the transfer relationship is complex, which brings passengers travel obstacles in the subway; It is difficult to find specific service facilities: there are many service facilities in the station, and the lack of guidance signs makes it difficult for passengers to find specific facilities; More exits and less information: there are more exits and entrances in the subway station, so passengers cannot find the target exit in the first time; Buildings and traffic outside the station: traffic transfer information is less, passengers can not quickly transfer after leaving the station; In-station transfer, service facilities search, exit surrounding information, etc., all need the integrated navigation system for both inside and outside of subway stations support to improve passenger experience and operational services.
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Power supply design of ground regenerative braking energy utilization device

Liu Wei, Ma Qingan, Zhang Jian, Zeng Jiaxin, Yang Qianfeng

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Energy feedback system and energy storage system are widely used in urban rail DC traction power supply system. Aiming at the design of the power supply system with ground regenerative braking energy utilization devices, this paper firstly builds the power supply calculation models of different ground regenerative braking energy utilization devices. Based on these models, the theory of optimal design and operation of power supply system are proposed, which takes the comprehensive cost of the system within the lifetime of the regenerative braking energy utilization device as the objective function in designing phase, and the system traction energy consumption as objective function in operation phase. Aiming at the energy-saving effect evaluation of the power supply system with ground regenerative braking energy utilization devices, two energy-saving effect evaluation indexes are proposed, which measure energy from traction energy consumption and main transformer energy consumption respectively. The on-line monitoring and control system based on energy-saving effect evaluation is proposed. Finally, some ideas of system designing of power supply system that should be adjusted are listed, which provide some reference for the system design.
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Test and Dynamical simulations of Guided Rubber-tyred tramfor the carrying capacity

HOU Xinying, WANG Zhihua, MA Kai, CAO Huamin

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This paper describes the results of Test and Dynamical simulations of Guided Rubber-tyred tram for the carrying capacity based on Urban road. This paper introduces the structure and main technical parameters of the Guided Rubber-tyred tram, and introduces the working principle of the guide mechanism and the articulated. A finite element analysis, kinematics of bogie and carbody based on SIMPACK and MSC ADAMS was focused on the introduction of the DOF (dimension of freedom), and the interference of the mechanism was checked on minimum radius(R=15m) 、S type curve and transition curve radius (R=200m) climbing steep (i=13%), etc,. And Measure the relatively rotation displacement between car body and main structure. Verify the sample tram of the reasonableness by the test. The test results agrees well with numerical simulation; the operating relationship meets the vehicle"s operational requirements.
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Influence analysis of track longitudinal irregularity based on inertial reference method

刘堂辉, 刘锦辉, 冯青松, 许晨霄, 刘文武, 罗信伟

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In order to study the influence of track structure sensitive factors on medium and long wave longitudinal irregularity, a vehicle track coupling model is established. Based on inertial reference method, the track longitudinal irregularity is simulated and detected, and the influence of track structure vibration and different fastener stiffness, subgrade support stiffness and sleeper spacing on the longitudinal irregularity is analyzed.The results show that the estimated irregularity of flexible track is significantly larger than that of massless track in the wavelength range of 2~6m; From the perspective of time domain, the fastener stiffness, subgrade support stiffness and sleeper spacing have little influence on the longitudinal irregularity, while from the perspective of frequency spectrum, the track spectrum changes obviously and mainly affects the longitudinal irregularity in the wavelength range of 2~4m, 2~10m and 2~3m.Therefore, the analysis of the distribution characteristics and development of track irregularity should be combined with amplitude and track spectrum angle.
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Reform and Countermeasures of Urban Railway Network Planning Under the New Situation of Territories Spatial Planning

JIANG Yong

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Under the new situation of the territories spatial planning, from the perspective of rail transit as an important supporting factor for the high-quality development, taking the practical work experience of Ningbo as an example, this paper expounds the reform and countermeasures of rail transit planning in four aspects: planning concept, means, scope and system. It is considered that the comprehensive and balanced development concept should be followed, "Inventory Planning" should be followed in the planning means, the planning scope should be extended to regions, "Collaborative planning" should be strengthened in the planning system. It is necessary to study the relationship between cities and rail transit, space control to rail transit, and comprehensive transportation integration.
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Design and Research on plane alignment of straddle monorail broken line turnout

WU Shu-qiang

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Turnout is one of the key technologies of straddle type monorail transit system. Its function is to realize the turning and turning operation of straddle type monorail vehicles in the process of driving and the shunting function in the vehicle base. Through the research on the plane alignment of broken line turnout, this paper summarizes the design method and key parameters of the plane alignment of turnout, verifies the turnout alignment given in the design standard, and puts forward design suggestions for the alignment design and expression of turnout.
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Design and Innovation of Foshan Metro Operation Management System

Sui Jiabin

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Foshan Metro adopts the mode of integration of production, operation and business to build the operation management system, which is committed to breaking the barriers between operation and management objects and operation and production business, and realizing data exchange among various businesses. By studying and analyzing the relationship between Foshan metro operation business, the model of Foshan metro operation business and the business relationship diagram of asset and equipment integration are obtained, so as to determine the business requirements of each major functional module in the system. Dependency injection is used to solve the problem of business linkage between equipment assets and maintenance and to realize the whole lifecycle management of assets and equipment. In the construction scheduling and construction management module, the graphical construction interface and the automation of construction condition audit are regarded as innovative requirements. It lays the foundation for the enterprise informatization business integration construction and data island management, and contributes Foshan’s experience to the informatization construction of the industry.
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Analysis and Suppression Measures of Catenary Residual Voltage in Urban Rail Transit

Ci Mingyang

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The catenary residual voltage issue of DC traction power supply system is common in urban rail transit. This issue is a direct threat to the safety of the operators and maintenance personnel. It shows that the catenary is energized during the electrical inspection for power outages. This will lead to the failure of normal operation and maintenance, and the failure of the line test. This also affects the normal operation of substations. This paper takes Fuzhou Metro Line 2 as an example, which has the catenary residual voltage issue at the entrance and exit lines of Zhuqi parking lot. The causes of the catenary residual voltage issue were analyzed based upon the theoretical analysis and calculation, combined with the residual voltage test data collected from experiments. Furthermore, the measures to reduce the catenary residual voltage were proposed. The on-site test results demonstrated that the proposed measures can effectively suppressed the catenary residual voltage.
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Early-Stage Study on Urban Rail Transit Network Planning Revision

Feng Jia, Mao Baohua

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The theoretical and practical research on using the extra capacity of rail transit passenger lines to provide freight services is in the ascendant, which can be divided into two modes: adding dedicated freight trains into passenger trains timetable and using the residual space on passenger trains to fix freight transportation. At present, the theoretical research mostly focuses on the optimization of mixed passenger and freight transportation scheme and timetable, and the practices mostly concern how to fix small freight demand using the residual space on passenger trains. Based on the empirical cases of Japan's North Vietnam express line, high-speed rail express, Taoyuan airport MRT and German parcel intercity (PIC), this paper summarizes the characteristics of two transportation organization modes. The organizational scheme of using the residual space on passenger trains to fix freight transportation is mainly used to meet the scattered freight demand. When using the carriage space, necessary fixed facilities shall be provided to ensure safety. Separation of transportation and loading can improve the loading and unloading efficiency and reduce the interference to passenger transport operations. In the case of adding dedicated freight trains into passenger trains timetable, the speed of the freight trains should be close to the adopted passenger train speed, and the transport process organized at night can ensure timeliness.
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Research on passenger flow efficiency improvement strategy of Tianjin Rail Transit

万

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天津是继北京之后中国大陆第二个拥有地铁的城市,但网络总体客流量偏低,运行效能不高。本文分析了天津市轨道交通客流的网络特征,识别当前影响天津市轨道交通客流提升的主要问题,最后提出近期、中期、远期提升天津市轨道交通客流的策略。 Tianjin is the second city with Chinese mainland's subway after Beijing. However, the overall traffic volume of the network is low and its operation efficiency is not high. This paper analyzes the network characteristics of Tianjin rail transit passenger flow, identifies the main problems affecting the passenger flow improvement of Tianjin Rail Transit, and finally puts forward the strategies to improve the passenger flow of Tianjin Rail Transit in the near, medium and long term.
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A Model Test Study on Natural Ventilation Characteristic of Subway Station

Zeng Zhen

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As an energy-saving measure, natural ventilation has been widely used in civil buildings, and its application prospect and effect in subway engineering are worthy of further study. Taking Shapingba Station of Chongqing Metro Line 1 as the prototype, the natural ventilation scale of the subway station under different working conditions is tested by building a natural ventilation model test platform of the subway station and simulating several typical working conditions in the public area. The test results show that hot pressing is one of the main driving forces of natural ventilation of the subway station, and the height difference between the subway exits has limited influence on it. The natural ventilation path is mainly composed of the subway exit, the station hall layer, and the subway exit, and the scale of natural ventilation flowing through the platform layer is small. Appropriately increasing the number of exits can increase natural ventilation and effectively promote natural ventilation efficiency. According to the test results, the corresponding design and operation suggestions are put forward, and the feasibility basis for making full use of natural wind energy saving in non-air conditioning seasons is put forward.
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Discussion about the influence of subway station on groundwater seepage in underground water rich city

GAO Yang, WANG Xin, ZHANG Kang, LEI Bingxiao, ZENG Chunpin

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With the construction of a large number of underground projects in water rich areas, the environmental problems of the changes of groundwater seepage conditions caused by underground engineering are becoming increasingly prominent. In this paper, the groundwater seepage when the subway station has not been built has been analyzed based on the one-dimensional seepage theory. Combined with the mirror image principle and superposition principle, meanwhile, the influence mechanism of the subway station on the groundwater seepage has been analyzed also, and the analytical formula of backwater height and groundwater flow due to the barrier effect of subway station was obtained. By the theoretical formula obtained in this paper, the backwater height and groundwater flow of of a subway station in Jinan nvcaused by the blocking effect of the station was analyzed, and the recommended value of anti floating water level considering the backwater was put forward. According to the analysis in this paper, the backwater height caused by the blocking effect of station structure is related to the influence radius of aquifer and hydraulic gradient. In practice, the possible backwater height after the completion of the subway station should be paid more attention to by the engineering personnel when encountering a strong permeable aquifer with a certain hydraulic gradient.
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Combined reinforcement method and application of Shield Launching Hole in soft and watery strata

ZHAO Hequan

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There were various accidents likely to occur when shield tunnel launching in high water head and slit strata. Surface grouting, freezing and other methods were often used to pre-reinforce the initial strata in Shield Launching Hole. Combined with strata characteristics in tunnel of Wangjiang road, this paper put forward a combined reinforcement of triaxial mixing pile, high pressure jet grouting pile as well as local freezing. This paper introduced the determination principle of reinforcement parameters and effect evaluation. Field test showed that all the conditions meet the design requirements. Tunnel launched successfully and it can be a reference for similar projects.
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Forecast of Short-term Passenger Flow of Urban Rail Transit Based on VMD-GRU

wujuan

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Precise passenger flow forecasting is the basis for rail transit planning. Based on the dynamic, nonlinear, uncertain, periodic, non-stationary and sequential characteristics of urban rail transit’s short-term passenger flow, this paper proposes a combined model prediction method to improve the prediction accuracy of short-term passenger flow, namely VMD-GRU neural network prediction model. This model is composed of variational mode decomposition and gated recurrent units to realize forecast of short-term passenger flow of urban rail transit. According to the data of Nanjing Metro, the model has a good effect on the short-term passenger flow prediction, and is superior to single models such as SVM, BP, GRU, and hybrid models such as VMD-SVM and VMD-BP. It can provide effective data support for subway operation management departments in terms of passenger flow management at stations and the formulation of daily driving plans, thereby improving the overall operating efficiency of the line network and the service level of the rail transit system.
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Research on Construction and Operation Characteristics of Straddle Monorail With Different Functional Types

ZHOU Qi, MAO Bao-hua, HUANG Jun-sheng, LIU Song

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Straddle monorail provides a new way for small and medium-sized cities to develop urban rail transit. Through the investigation of application of straddle monorail lines in the world, it is concluded that straddle monorail has not been widely used in the world at present. According to the functional types and geographical environment characteristics of the line, the straddle monorail in operation can be divided into four types: sightseeing, connection, densification and backbone; this paper studies the construction and operation characteristics of straddle monorail with different functional types from the aspects of investment efficiency and operation mode, providing experience for the development of straddle monorail: deepen the research on the adaptability of straddle monorail system and passage passenger flow. Promote the integration of straddle monorail line and urban comprehensive transportation network. Combined with function types and passenger flow characteristics, the transportation organization mode is applied. It is worth noting that the straddle monorail will have high marginal cost under the background of technology not highly standardized in China.
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Analysis and Apocalypse of Tram Construction and Operation Characteristics in Brunswick, Hanover and Munich

LIANG Shuaiwen

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In recent years, tram is in the stage of steady development in China. In order to better realize the sustainable development of tram in China, it is necessary to actively learn from the mature construction and operation experience of foreign countries. Germany, which has the largest tram line network in the world, can provide rich case study and reference for China in this respect. First of all, the system characteristics of german trams are analyzed, on this basis, the standard of case selection is put forward, so that the selected cases can keep the same with domestic trams in the system. Then, the trams in Brunswick, Hanover and Munich are selected as the study cases to analyze the construction and operation characteristics of trams in small, medium-sized and large cities in Germany. There are some differences in the function, characteristics of line, passenger, operation of tram in different scale cities. Finally, combining with the case analysis, from the aspects of function positioning, line construction standard, operation and crossing road setting, transfer and connection, hub station construction standard and so on, this paper puts forward the enlightenment to the development of tram in China.
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Passenger Flow Control of Urban Rail Transit based on Deep Q-network

zhanghui, guojianyuan, tangyuxin, dujiamin

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In view of the urban rail transit safety problems caused by limited transport capacity for passenger demand in peak period, it is necessary to adopt passenger flow control strategy to adjust the inbound passenger flow and alleviate station congestion. In this paper, a multi-station cooperative control model based on reinforcement learning deep-q network is proposed to optimize the arrival number of each station in a certain period of time. The goal is to minimize the comprehensive benefits of platform overrun, average waiting time and passenger flow control intensity. Taking Beijing Metro Batong line as an example, the simulation results verify the effectiveness of the method. The simulation results show that the model can effectively reduce the waiting time of passengers and improve the travel efficiency of passengers under the condition of low passenger flow control intensity. The method is helpful to alleviate the passenger congestion at the station without reducing the travel efficiency of passengers.
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Supercapacitor Technology for Urban Rail Transit

邓谊柏, 黄家尧, 陈挺, 冯少玉, 李婷婷, 杨颖

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Supercapacitors have high power density (2kW/kg to 15kW/kg), long cycle life (100000 to 1 million times), wide operating temperature range (-40℃ to +70℃), and high energy conversion efficiency（greater or equal to 90%）, in the field of rail transit, supercapacitor can be used as energy storage tram power supply, regenerative braking energy ground energy storage system, and internal combustion engine auxiliary starting device This article introduces the basic principles of supercapacitor energy storage, systematically explains the cell preparation process and module configuration methods, summarizes and compares the technical characteristics of major domestic and foreign manufacturers, domestic electric double-layer supercapacitors have achieved mass production of the world's largest cell capacity of 12000F, and the technology is at the leading level in the industry. Finally this article analyzes the factors which affects the service life and safety of the supercapacitor energy storage device, and looks forward to the future research and development direction of the supercapacitor system for rail transit.
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Overview of Energy Management Strategy for Wayside Energy Storage System of Urban Rail Transit

Liu Yuyan, Lin Fei, Yang Zhongping

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Wayside energy storage system is one of the effective ways to recover regenerative braking energy in urban rail transit. The wayside energy storage system can realize the functions of energy saving, voltage stabilization, peak shaving and emergency traction. The energy management strategy of energy storage system is the cornerstone of achieving these control goals. Firstly, the composition and control of wayside energy storage system are briefly introduced in this paper. Then, the research status of energy management strategy of wayside energy storage system is summarized based on design ideas and problem objectives and the characteristics of different energy management strategies are analyzed. On this basis, the research prospect of the future energy management strategy for wayside energy storage system is discussed. By exploring current and future energy management strategies, it provides reference for the development of wayside energy storage system.
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Review of energy storage technology of lithium titanate battery for rail transit

Wu Jian, Zhang Yanru, Zhang Linjing

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In recent years, with the continuous improvement of operation reliability, energy saving and environmental protection requirements, as well as the continuous improvement of new energy storage technology, the application of on-board energy storage technology in rail transit rolling stock has been developed rapidly. With high energy density, wide temperature range, long cycle life and high safety and reliability, lithium titanate battery has been widely used in urban rail transit. Based on the energy storage technology of lithium titanate battery, this paper analyzes the applicability of lithium titanate battery in rail transit from the aspects of development, performance characteristics and application scenarios of lithium titanate battery, and expounds the technical problems in the process of lithium titanate battery grouping. Finally, facing the application scenarios of large-scale and long-time operation in the future, from the aspects of life evaluation, performance characteristics and application scenarios of lithium titanate battery The existing problems and research hotspots in the application of lithium titanate are summarized and prospected from three aspects: optimization matching and efficient energy management of vehicle energy storage, and data analysis of off-line / on-line life cycle battery.
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Study of Domestic and Foreign Standards for Urban Rail Transit Wayside Energy Storage Technology for Recycling Use of Train Residual Regenerative Brake Energy

Hu Bin, Lin Fei, Yang Zhongping

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The type of energy storage technology is various, and the technology is widely used. Domestic and foreign countries have formed multiple standards, especially in the fields of power grids and electric vehicles, which the standard system has been very mature and perfect. In the field of urban rail transit, energy storage technology is relatively lack. In this paper, the domestic and foreign standards are combed and classified, then three storage technology standards in the field of urban rail transit are studied, finally the classification and interpretation are summarized, and related suggestions such as: strengthen energy storage system security requirements, accelerate the construction of urban rail storage technology standard system, imitate life assessment of energy storage units and simulation methods in international standards are given.
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Centralized Control and Protection Scheme for Urban Rail Transit Network Security

LiuKui

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This study expounds the disadvantages of the current network security solutions of various systems, by analyzing the main network security risks faced in urban rail transit. Starting from the urgent needs of safety response coordination and linkage, centralized operation and maintenance of safety equipment, unified sharing of safety resources, overall deployment of safety personnel and top-level planning of safety management, the study come out with the solution of a centralized control and protection of network security proposal. This proposal realizes the functions of cross system collaborative monitoring, defense, detection, response, prediction and analysis, so as to form a perfect urban rail transit network security protection system and effectively resist various security threats. Furthermore, it will adapt to the digital and intelligent dynamic multi-dimensional security environment in the future.
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Study on Spatial Gradient Characteristics of Land Use around the Urban Rail Transit Stations

WANG Shuling, ZHANG Zhening, FU Haoyang, PENG YUFEI, JIANG Xi

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The elaborate analysis of the land use around the urban rail transit stations is needed in the integrated planning of rail transit and city. The purpose of this paper is to qualitatively and quantitatively study the spatial gradient characteristics of land use. Firstly, using the K-means method, this paper explored a method to identify the morphological characteristics of spatial gradient of land use. Secondly, based on improved TOPSIS model, this study proposed a quantitative evaluation method of the spatial gradient characteristics. Finally, the results of a case study about Beijing rail transit network showed five morphological modes and quantitative evaluation of spatial gradient, and provided methodological basis for promoting the integrated and coordinated development of rail transit and city.
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Comparative research on data-driven energy prediction models for underground subway stations

王岩, SU Ziyi, LI Xiaofeng, 王斌

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Abstract:

This paper has compared a variety of commonly-used data-driven methods in the field of energy prediction model of the ventilation and air-conditioning (VAC) as well as vertical transport (TRANS) in subway stations, including least square multiple linear regression, Ridge regression, Lasso regression, random forest, XGBoost. It is found that the CV-RMSE indices of the afore-mentioned methods are less than 10% for the VAC and TRANS energy prediction, the accuracy of which are adequate for the engineering application. Among them, the CV-RMSE of XGBoost is only 5.1% for the VAC model and 5.4% for the TRANS model, which is obviously better than other algorithms. From the perspective of computational cost, the least square regression, Ridge regression and Lasso regression algorithms have comparatively low cost, while the random forest and XGBoost models have high computational cost. In this paper, by comparing the prediction accuracy and calculation cost of the commonly-used data-driven methods, the algorithm reference for the development of subway station energy prediction model is provided.
1
Research and Design of Prefabricated H-shaped Slab-Column Combined Track Structure for Urban Rail Transit

duanyuzhen

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At present, the columns of the column inspection pits in the parking garage of urban rail transit depots basically adopt the form of cast-in-place concrete structure，and a few adopt steel structure, column or precast concrete small column structure. Conventional column scheme has many construction operations, construction accuracy is not easy to control, construction progress is slow, and construction quality is difficult to control. It is difficult to meet the requirements of construction period, construction precision and aesthetics of urban rail transit. In this paper, the advantages and disadvantages of the conventional cast-in-place concrete column scheme, steel column scheme and precast concrete small column scheme in design, construction precision control, construction quality control and engineering cost were systematically investigated, and a precast H-shaped slab and column composite track structure scheme was developed. Compared with the conventional scheme, this scheme has the characteristics of simplifying operation links, reducing labor intensity, improving construction accuracy, improving construction efficiency and enhancing its aesthetics, etc., and realizes the structural assembly to the greatest extent, which provides a good reference and reference for solving the problems related to the inspection pit structure of the columns in the car depot parking garage.
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Discussion on key problems of interconnection construction of rail transit AFC system in metropolitan area

ZHANG Peng, WANG Jian, LU Bin

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In order to create "one hour commuter circle", build "urban agglomeration and metropolitan circle on the track", and form a new pattern of "one ticket" interconnection, it is very necessary to establish the interconnection mechanism of automatic fare collection system of urban rail transit between cities. This paper analyzes the key problems restricting the development of AFC system interconnection from the perspectives of standards, ticket vouchers, billing and preferential methods and the current situation of interconnection construction. This paper puts forward suggestions on the construction of AFC system interconnection from the perspectives of system architecture, standard preparation, Interconnection of ticket vouchers and ticketing management interconnection, so as to provide reference and reference for the subsequent integrated construction of ticketing operation of AFC system in metropolitan area.
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Research on improving the integrated development strategy of Beijing Urban Rail Transit

zhangna, maxin

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In recent years, the rapid development of Urban Rail Transit in Beijing has played an important role in easing traffic congestion, improving the efficiency of public transportation and improving the punctuality of transportation, however, there are still some deficiencies in the convenience and integration of Rail Transit. Through the Special Investigation and research on the integration of Urban Rail Transit in Beijing, 110 rail stations were selected, 2,400 samples were collected from the survey below the line and 1,000 samples from the survey on the line, this paper summarizes the status quo of the integration and convenience of Beijing Rail Transit. In response to the conclusions of the investigation and analysis, this paper puts forward some countermeasures and suggestions on strengthening the initial unified planning and design, optimizing the layout and operation connection of the transportation hub, deepening the service level of the existing stations, promoting the repair of the station connection function, and so on.
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Study About Induced Voltage on Overhead Catenary Line in Adjacent Tunnel of Rail Transit

CAO XIAOBIN

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Some rail transit system in China adopts the power frequency single-phase AC system to improve the running speed and transportation capacity of trains. When the traction power supply system fails, the one-side power outage emergency repair scheme may be adopted. If the induction voltage on the catenary is too high, it will cause harm to maintenance personnel. In this paper, a simulation model of subway tunnel was built based on the design data of a subway. The induced voltage on the overhead catenary line is obtained When it is cut off for maintenance, and the other side of the line is in normal operation. Influences of the traction current, the distance between the tunnels and other factors on the induced voltage are also gotten. It is found that the inductive voltage on the overhead catenary line will exceed the safety level when the single-ended grounding mode is adopted. If the double-ended grounding mode is adopted, it will be reduced below the safety limit. According to the above research results, proposes were given in this paper that when the subway unilateral power outage maintenance operation is adopted in the AC power supply system, the both ends of the maintenance interval must be grounded. The conclusion of this paper can be used as a reference for the subway management department to formulate safety measures.
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Long-term settlement prediction model of metro shield tunnel based on machine learning

Zhang Yanqin, Di Honggui, Xu Yonggang

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Based on advanced regional geological information and tunnel settlement data, a long-term settlement prediction model of shield tunnel using machine learning method was proposed. The model was demonstrated by a case study of Nanjing Metro Line 2 shield tunnel. The results show that the prediction model can analyze and obtain the main influencing factors of long-term tunnel settlement and find the best supervised learning algorithm and optimal parameters. Among the different supervised learning algorithms, both the kernel support vector machine (KSVM) algorithm and the artificial neural network (ANN) algorithm can achieve high accuracy, but require careful parameters adjustment to improve the prediction accuracy. Using the ANN algorithm as supervised learning algorithm and after parameters adjusting, the final prediction accuracy of the model can reach 0.86 and the average accuracy of tenfold cross-validation is 0.82.
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Design and Implementation of Urban Rail Transit Construction Project Progress Visualization Management System

cui wei

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In order to meet the demand of visual management and control for rail transit construction project progress management, a visual management system for urban rail transit construction project progress is proposed and implemented.The system is based on the establishment of a project schedule management and control system, using data calculation model construction and data visualization display technology, combined with the project schedule weekly report management requirements, to achieve the visual management and control of the project construction image progress management.Combined with the information management platform, it provides an operation platform for the subway construction project schedule management personnel to standardize, visualize and integrate the construction progress of the entire subway network, the construction progress of each line, and the construction progress of each station.Improve the management level of rail transit construction project schedule management, and reduce the management cost of schedule management and control.
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Analysing the Influence of Train Operation Disturbance in Urban Rail Transit Based on Historical Data

Liu Fengbo

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The process of train operation is affected by many disturbance factors, which may cause train delay and affect passengers. In order to identify the disturbance and estimate the influence, a novel approach based on historical data of urban rail transit is proposed. According to the emergency disturbance and its related multi-source data, such as train operation record and automatic fare collection data, the generation and influence law of the disturbance were analyzed. The main contents include the classification, causes and occurrence law of the disturbance, as well as the duration, spatial range and relative passenger flow rate under the disturbance. The case study of a city shows that: disturbance events were more likely to occur in peak hours, and vehicle failure was the most common cause. More than half of the disturbance events could be eliminated in 30 minutes. The delay caused by disturbance mainly occurred on the follow-up trains and at the stations in front of the occurrence location. The passenger flows decreased in the first half hour, then increased or even exceeded the normal standard ones, which coincided with each other about two hours.
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Research on establishing the engineering construction standard system of urban metro transport

Chen Minghao, Xu Ling, Zhu Shengli, Huang Qiwu, Li Yuankai

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The engineering construction standard system is a important basis which control safety and quality, Standardize while upgrade process and technology in urban metro transport engineering construction. Based on Hall three-dimensional model firstly, establish the layers and basic structure of standard system by dimensional analysis. Next analyze the main work and auxiliary work in the project construction by value chain of engineering construction, thus Classify and integrate specific standards. Finally, use the taxonomy to subdivide the specific standards of design, construction and acceptance. Later, build the structure graphing and list of standard system further. Thus the engineering construction standard system of urban metro transport which is intact and conform to general features has been established.
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Application of single degree of freedom rail resonator in rail wave grinding treatment

wusaijia, nihao, xuejiaxin, yuquanyu

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Rail corrugation diseases in subway operating lines are becoming more and more common, among which short-wave corrugation with a single wavelength of 20 to 80 mm is the most typical. This article comprehensively introduces the experimental research and application effect of a typical howling-type corrugation treatment plan with a wavelength of about 25mm and a dominant frequency of howling noise of about 735Hz on a certain section of the Tianjin Metro. On the basis of the proposed single degree of freedom rail resonator treatment plan, the rail attenuation rate analysis model was established, the mass, stiffness and damping of the resonator and other key technical parameters were studied and analyzed, and the rail vibration acceleration before and after the installation of the resonator and The interior noise was measured and compared. The measured rail vibration acceleration level at the main frequency of the corrugation at 735Hz was reduced by 19.0dB, and the interior noise level was reduced by 11.9dB, indicating that the single degree of freedom rail resonator improves the wheel-rail dynamic relationship and vibration characteristics, which can effectively control the howling rail corrugation and provide reference for the treatment of similar diseases in subway.
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Research on Train Planning Optimization for A/B/C Skip Stop Operation without Transfers in Urban Rail Transit

YANG ANAN, wangbo, chen shaokuan, 张翕然

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With the rapid development of urban rail transit and the need to promote high-quality development, higher requirements have been put forward for the operation and organization level. For the lines without overtaking facilities, it is important to improve the train speed by optimizing the train stopping plan. Based on the traditional A/B skip-stop mode, this paper proposes A/B/C skip-stop mode to achieve time-saver without transfers. Firstly，the characteristics of all trips under various stopping patterns are investigated, and an mixed integer programming model with stopping patterns and frequencies as decision variables are constructed. Additionally, a genetic algorithm (GA) is developed based on the model. Finally, the effectiveness of the proposed model and heuristic algorithm is verified through a set of real-life instances based on the Beijing Metro Line 6. The results show that the travel time and in-train time can be reduced by 2.15% and 6.79% respectively without transfers. If taking no account of waiting time, the in-train time can be reduced by 14.25%.
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Research on the type of time distribution of passenger flow between urban rail transit stations based on spectral clustering

YAO ZhenKang, GAO Guofei, ZHENG Han, HUANG Zhaocha

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In the process of rail transit operation management, the characteristics and rules of time distribution of passenger flow between different stations directly determine the passenger flow organization scheme. The clarification of inter-station passenger flow time distribution types is beneficial to the reasonable configuration of passenger flow organization scheme. In this paper, we firstly analyze the classification characteristics of inter-station passenger flow from three perspectives of time, space and structure, and compress the search space of classification by spectral clustering method to achieve more accurate type classification. The classification results of different methods are compared using Silhouette Coefficient and Davies-Bouldin Index, and it is demonstrated that the proposed spectral clustering method has better classification results compared with other methods such as k-means. Taking Suzhou Metro 2020 data as an example, seven types of inter-station passenger flow time distribution are found by the proposed method, and the results can be applied to areas such as prediction model training.
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Research on the Establishment of Standards System for Urban Rail Transit

LI WENYING, LU FANG

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Major changes have taken place in urban rail transit standards along with the reform of the national standardization work. Timely establishing and keeping improve a standard system that meets the needs of the urban rail transit industry as well as the speed of development, will create benefits to build an organic system that including various types of standards in urban rail transit area, and improve the quality of standards, strengthen the influence of standards, promote technology innovation, and meet the needs of the urban rail transit industry's continuous, healthy and high-quality development. This paper briefly investigates and analyzes main body of the construction of urban rail transit standard system, summarizes existing urban rail transit standard systems, and analyzes their applicabilitys. Proposes the technical route, working principles, establish goals and main construction content of the urban rail transit standard system, and proposes the application scope and structure of the urban rail transit industry standard system, as well as the suggestions of key research and development areas. It is expected to actively promote China’s urban rail transit standards’ work, leading the development of the industry, promote the construction of a strong transportation country and the construction of smart urban rail, as well as occupying a more important position in the field of international standardizations.
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Simulation Analysis of the Effect of Train Operating Conditions on DC Bias of Power Transformer

YANG Feng, LI Chun-mao, GUO Yu-jun, CAO Xiao-bin

Abstract: (134) HTML (0) PDF (0.00 ByteKB) (0)

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With the rapid development of economic construction and the continuous expansion of urban scale, in order to solve the contradiction between the supply and demand of urban transportation, my country has vigorously developed urban rail transit construction in recent years, forming a complex urban rail transit network in large cities. A large number of cases have shown that the stray current in the subway will affect the surface potential distribution, and if there is a power transformer nearby, the DC current flowing through the transformer will cause the transformer to be DC biased. However, the current situation regarding the subway surface potential distribution There are few researches on the influence of DC bias of surrounding transformers. For this reason, this paper considers four different operating conditions of train up and down, builds a subway surface potential simulation model, and calculates the transformer excitation current distortion rate under corresponding conditions, and obtains the up and down When the trains leave the station at the same time, the conclusion that has the most serious impact on the DC bias of the transformer provides a theoretical basis for preventing the DC bias of the power transformer.
1
Planning and Construction Standard of Suburban Railway

Guo Kai

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In recent years, many official documents to promote the development of suburban railway are released by government. The author interprets the main guideline of the official documents; summarize the similarities, differences and characteristic of many design specification and standard. By combine the practice of suburban railway planning and design, the author put forward some technical opinion about the definition, line planning, technical standard, traffic volume, operating mode and transportation management of suburban railway. With all efforts by colleagues of the field, to adopt the economical, practicable, efficient technical standard and construction option, provide the mass transit service, reduce the construction and operation cost, increase the project economic benefit, to promote the long-term sustainable development of suburban railway.
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R & D and application of New Type of Integral Casting Slider Chair for Urban Rail Transit Turnout

Zhang Hong-liang, Zhang Zhen-yuan, wujiangzhong, Chen Peng, XIN Tao, Wang Min

Abstract: (8) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

Slider chair is located under the switch rail and stock rail components in the turnout, it support the switch rail and clamp the stock rail within the range of the switch rail. Slider chair is the key equipment, its normal operation is directly related to the operation safety. As common diseases, welding-off of sliding plate and baseboard, fracture of the slider chair, it has been the focus and difficulty of the maintenance work in the turnout area for a long time. Developed a new type of integral casting slider chair in order to thoroughly solve the problem of the disease of the slider chair. The optimization design of the slider chair, including manufacturing process, material optimization, increasing the width of the tongue of slider chair and the radius of the tongue’s root were introduced in this paper. The on-line test section is carried out after the excellent mechanical properties of the slider chair were verified by theoretical analysis and ultimate failure strength test. The successful development and application of the new integral casting slider chair is of great significance for the radical cure of the slider chair disease in the turnout.
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Discussion on the Implementation Path of Kunming Rail Transit Transit-Oriented Development under New Situation

Peng Wei

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The urban rail transit in China is reaching a great upsurge in construction. How to integrate rail transit with the city through the TOD mode, and make rail transit construction and operation enter a virtuous circle has become a hot topic. Kunming is the economic and cultural center of Yunnan, the development of TOD in Kunming is still in progress, and the practical experience needs to be studied. The domestic urban development trend has changed from rapid and incremental to optimization and stock. "Efficient and green" has become the key word. TOD guiding urban development is one of the best ways to achieve this goal. This article draws on the practical experience of domestic city, especially pays attention to the existing policy documents of other cities in China, combined with Kunming's own characteristics and critical problems in the development of TOD, and puts forward suggestions on the direction of comprehensive development of urban rail transit in Kunming in the future, paying special attention to the thinking about the implementation path of TOD localization.
1
Security Analysis of Resource Management Unit of Vehicle-vehicle Communication Train Control System

Liu Zhenyu, Li Jing

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Based on the traditional train ground communication, the train control system introduces the train ground communication technology to realize the real-time communication between the rear train and the front train, which greatly simplifies the ground equipment and improves the train operation efficiency. This paper used STPA method to analysis the security ofresource management unit, the key equipment of the system. The process of Temporary Speed Restriction sending by RMU is studied as typical of the control scenario. The dangerous behaviors in the process are identified, the unsafe factors of the system are found out, and SDR is formulated in the scenario. The timed automata network model of TSR sending scenario is built by SDR condition, and UPPAAL is used to verify the model. The verification shows that STPa method can find the control defects in the train control system, and adopt corresponding strategies to improve the security of the system, which has good applicability in the security analysis of the train control system.
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Study on the business system migration of independent controllable cloud platform for Urban Rail Transit

LV Guangjie, LIU Qingliang, WU Chao, FAN Yibo

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The cloud platform of urban rail transit is highly dependent on the foreign technology, and there is a risk of "sticking neck" in the key segments. This paper analyzes the current situation of this field, puts forward the corresponding solutions, specifically expounds the model of urban rail transit independent controllable cloud platform, puts forward the feasibility evaluation method of urban rail transit business system independent controllable cloud platform migration, and introduces the migration principle and method. Then the paper introduces the implementation path of middleware migration, database migration, application migration and solutions to typical cases. This paper effectively solves the "neck" problem of urban rail transit cloud platform, and explores a set of independent controllable cloud platform construction and implementation scheme.
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Application of BAS Automatic Mode Control Technology in Metro Environmental Control

Zhang Zhipeng, Ren Guanbing

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Abstract:

Building Automation System (BAS) is an indispensable and important part of urban rail transit operation management system, Its function is to realize the automatic monitoring of the station environment and electromechanical equipment, and provide a comfortable environment for passengers and operators. According to the automatic adjustment of the temperature and humidity of the subway environment, it is necessary to use the corresponding ventilation mode to control the ventilation environment of the station, and realize the purpose of efficient operation, energy saving and consumption reduction through calculation applications. This article introduces the application of BAS and ventilation system automatic mode control technology in subway environmental control, and details the effect and purpose in the application process, etc.
1
Research on fare system under the background of integration of cross standard rail transit payment areas in metropolitan area

zhangsen, yumin

Abstract: (132) HTML (0) PDF (0.00 ByteKB) (0)

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Aiming at the integrated fare system of cross standard rail transit payment area in metropolitan area,Firstly, this paper investigates the ticket system of metropolitan areas such as Beijing Tianjin Hebei, Yangtze River Delta and Chengdu Chongqing in China, and metropolitan areas such as London, Paris and Tokyo in foreign countries,On the basis of summing up the experience at home and abroad,Analyze the objectives and principles of fare setting,It is the first time to put forward the scheme of "sectional taxi fare".In view of the problem of cross standard and cross regional fare calculation, it is recommended to adopt the same standard of "no segmentation, no restart" pricing and cross standard of "segmentation, restart" pricing.In terms of OD fare calculation, the lowest fare scheme is recommended by comprehensive comparison and considering the public welfare factors of rail transit.It also analyzes how to deal with the situation that the ticket price does not match the mileage, and each analysis is supplemented by specific examples to facilitate understanding.
1
Discussion on IPLV of Water Chillers Capacity in Underground Railway Stations

WANG Yizhen, LI Xiaofeng

Abstract: (205) HTML (0) PDF (0.00 ByteKB) (0)

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Chillers in the current subway environment control system are under partial load most of the time from a large amount of test data. This paper aims to revise the formula of the integrated part load value (IPLV) used to judge the comprehensive performance of the subway station chiller under partial load. This paper used a method of calculating the load of subway stations hourly throughout the year to obtain the hourly load curve in Beijing, shanghai and Guangzhou. Load rate sections in three cities were counted from the load duration curve. The result shows that partial load accounts for a high proportion in subway station air-conditioning season. The load rate below 25% accounts for nearly 1/3 of operating time, and the load rate below 50% accounts for more than 50%. Under the condition of setting up 2 chillers, the proportion of low load rate decreases, but is still higher than the group standard value. The result is instructive for subway air-conditioning system equipment selection and energy saving.
1
Spatial difference and organization pattern of urban land use around rail transit stations: A case study of Changchun LRT line 3

ZHANG Jie, HAO Fei-long, WANG Shi-jun

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Abstract:

In order to explore the impact of urban rail transit on the spatial distribution of land around the stations and the differences of land use functions, summarize the land use function organization modes around different types of stations, and guide the benign interaction between urban land use and rail transit, this paper takes Changchun light rail line 3 as an example to conduct empirical research. By using location entropy analysis and spatial analysis method, according to the POI data and land use status data of different land use types within 1000 meters around the station, the rail transit station types are divided, the surrounding land use function differences are analyzed, and the land use function organization model is abstracted. The results show that the stations of Changchun rail transit line 3 can be classified into two categories: single function type and mixed function type. The quantity and scale characteristics, specialization degree and mixed development degree of functional elements within the influence range of different mixed stations are different; The function organization mode of land use around the commercial comprehensive and traffic transfer stations is "single core unipolar axis", the commercial residential mixed stations are "dual core unipolar axis", and the public service and public mixed stations are "dual core multi polar axis".
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Analysis of Two Group Standards for Tunnel Wind and Fire Resistant Doorsets

WANG Yiran, LI Lie, FU Chao, ZHU Lan

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Because of the long-term influence of the train piston wind, the fire door in the cross-passageway of the urban rail transit has the risk of damage, falling off, threatening the train operation safety and even causing serious accidents. In order to reduce operational risks and ensure operational safety, the China Urban Rail Transit Association has organized two group standards, ” Wind and fire resistant doorsets of tunnel of urban rail transit” T/CAMET 05001-2020 and “Technical specification for tunnel wind and fire resistant doorsets engineering of urban rail transit” T/CAMET 05002-2020. This paper interprets the two standards from the background, main contents and main characteristics of the standards, so as to help the standard users to understand and grasp the standard clauses quickly and accurately, and to promote the implementation of the standards.
1
Structural Design of Large-span Column-free Metro Station co-built with Underground Complex

NIU Bin

Abstract: (47) HTML (0) PDF (0.00 ByteKB) (0)

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The Shijiazhuang CBD underground public space project is an underground complex that integrates supporting commerce, garages, energy centers, smart centers, municipal pipe corridors, civil air defense projects, and metro stations. In order to improve the service level of the station, the metro station adopts a large-span column-free scheme and a skylight on the roof. Based on the introduction of the underground space scheme, this article focuses on the analysis of the station’s forces and structural measures. The design scope includes: 1) Using the retaining piles as anti-floating piles; 2)Diagonal bracing is used to solve the vertical force of large-span column-free stations. The lower part of the diagonal brace is supported on the beam slab of the underground complex; the "arch effect" at the diagonal brace is solved by the long cross beam on the upper part of the diagonal brace; 3) The bottom plate is arched by varying the thickness to reduce the stress on the bottom plate and the connection between the bottom plate and the side wall; 4) The temperature stress calculation adds additional steel bars and post-casting to solve the temperature stress problem of mass concrete.The project has been completed，structure deformation and force has been controlled well,The research results can provide reference for the design of large-span column-free metro stations.
1
Evaluation Method of Overall Risk Grade of Metro Engineering Based on Fuzzy Comprehensive Evaluation Method

zhanghao

Abstract: (29) HTML (0) PDF (0.00 ByteKB) (0)

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Combined with the current safety risk management mode of most urban rail transit project construction in China, Evaluate the safety risk level of the site's own risks and environmental risks based on the safety risk assessment in the design stage of construction drawings. Based on the safety risk assessment in the construction drawing design stage, Using the fuzzy comprehensive evaluation method, a method of comprehensively judging the overall risk level of a work site that combines its own risks and environmental risks is proposed. A new idea is proposed for the safety risk assessment and management of the follow-up urban rail transit project construction.
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Kunming Rail Transit Project Experimental study and optimization of smoke exhaust system in typical railway station

lifuzeng

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Through the experimental research on the abolition of the rail exhaust ventilation system in the typical station in Kunming, the data of smoke exhaust and smoke exhaust in the platform layer of the Kunming area are obtained by using the non closed platform gate. The results show that the interval tunnel ventilation system is used to replace the traditional rail exhaust system, and the horizontal ventilation is adjusted to the longitudinal ventilation form. It can also meet the smoke exhaust function of the station platform and the rail line. It is reasonable and feasible to use the system model to optimize the design and Application of the engineering practice.
1
Type Analysis of Metro Stations Based on EM Algorithm and Gauss Hybrid Model

Han li, LI xiang, YAO qin

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Abstract:

this paper analyzed the differences of passenger flow curves by the Expectation maximization Algorithm (EM Algorithm) and Gauss mixed model. The stations were divided into seven types combined with the sum of squares error: living-oriented, career-oriented, living-employment dislocation, partial living dislocation, partial employment dislocation, transportation junction, synthesis. Finally, the correlation between the land types and station distribution of different metro station types were analyzed. The result shows that the distribution of different stations has a regional attribute. The number of metro types decreases as the distance from the city center increases. The types of stations in the central area are complex, which reflects the manifestation of the spatiotemporal differences in urban functional regions. This paper provides a new perspective for the study of urban space. It helps to understand the spatial distribution of urban functions and provides a foundation for future urban and transportation planning.
1
Fault Diagnosis of IGBT with Open-Circuit in Quasi-Z-Source Inverter

WU Yue, LING Zhujun, YE Xiaofeng

Abstract: (134) HTML (0) PDF (0.00 ByteKB) (0)

Abstract:

Aiming at the problem of safe and reliable operation of three-phase quasi-Z-source inverters, a fast and practical IGBT open-circuit fault diagnosis method of quasi-Z-source inverters is proposed. The new IGBT open circuit fault diagnosis is realized based on the characteristics of the Z-source inverter. The main method is to observe the influence of the change of the shoot-through state before and after the fault on the system variables during the switching period to identify the fault. The implementation is divided into two consecutive stages, one is IGBT open-circuit fault detection and location, the second is to activate the redundant bridge arm to complete the fault-tolerant operation. The tests were carried out with a low-voltage prototype of a three-phase quasi-Z-source inverter. The experimental results verified that the designed IGBT open-circuit fault diagnosis scheme can quickly detect IGBT faults, and complete the system reconstruction within 0.5ms to achieve fault-tolerant operation. The use of the proposed Z-source inverter IGBT open-circuit fault diagnosis scheme in the rail transit system can ensure the reliable operation of the power supply system.
1
Designs of Safety Intelligent Monitoring and Early Warning System for Urban Rail Transit Facility

Wang Bo, Teng Qian, Bao Feng, Song Xiaomin

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With the increasing scale of rail transit network and passenger volume, the requirements for safe operation of urban rail transit are higher and higher. Intelligent safety monitoring of urban rail transit facilities is an important guarantee for safe operation of rail transit system. In this paper , a safety intelligent monitoring and early warning system for urban rail transit facilities is designed, which can realize the functions of data collection, data transmission, data storage and intelligent early warning of rail transit facilities. Specific design requirements are puts forward for the system function and layout, and the early warning level are divided according to the safety requirements.
1
Deformation Analysis of T-shaped Transfer Metro Station under Horizontal Earthquake

lixia

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The underground rail transit system is an important part of the urban lifeline project. Among them, the transfer subway station is large in scale with large passenger flow, and the structure of it is complex. Its seismic performance is very worthy of attention. Based on the structure of a T-shaped transfer station, a three-dimensional dynamic time-history analysis model of the stratum-structure was established to simulate the dynamic response of the soil-T-shaped transfer station structure system under the action of earthquake loads. The displacement response law of the T-shaped transfer station structure under the action was analyzed. The calculation results show that the maximum displacement of the T-shaped transfer station structure and the maximum top-bottom displacement difference appear on the roof of the three-story line station. The minimum value of the structural displacement occurs at the T-shaped intersection of the two-line station. The research results of the thesis have certain reference significance for the seismic design and analysis of T-shaped transfer stations.
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The research of integreated design of metro depot and its real estate development for superstructure based on Guanggang New Town Metro Depot of Guangzhou metro

张

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Abstract:

Abstract:With the encryption of the urban rail transit line network and improvement of service quality, the numbers of metro depots are constructed. But the land for metro depots is difficult to be implemented because?it takes up too much space. In order to reduce damage to urban planning and restore the original function of urban planning, lots of depots adopt the form of Cover Development in first-tier cities. The purpose of this paper is to discuss how to combine real estate development for superstructure of metro depots with functions under the cover closely, and how to carry out the existing and planning boundary conditions for the metro depots with secondary development for cover plate so that the metro depots can be successfully landed in the urban core area in the future. Based on the analysis of the design scheme of Guanggang New Town Depot of Metro Line 10 in Guangzhou, this paper summarizes the features and matters needing attention in the integrated design of the under covered depots and the secondary-development cover schemes, which can provide reference for the future site selection and scheme design of metro depots in the core area of urban planning.
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Research of Prefabricated Residential Design Build on the Cover of URT Vehicle Base in Beijing

WANG Yutong, ZHENG Xin, XU Ning

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Facing the current implementation requirements of prefabricated houses in Beijing, the upper cover of vehicle base projects based on residential makes the exploitation of upper cover vehicle base which adopts prefabricated residential technology become a new research direction for the development of Beijing’s vehicle base superstructure. Relying on the development project of the upper cover of the Beijing rail vehicle base, this article discusses the integration of prefabricated housing and the upper cover of vehicle base development. And discusses the factors of how upper cover of vehicle base development influence the prefabricated houses from four dimensions—planning scale, individual building, structural load and railway operation. Combined the exploitation of Beijing Dongxiaoying upper cover Depot project, we analyzed the feasibility of exploiting prefabricated houses on upper cover of vehicle base, proposed the main points of reserved engineering design, intend to provide references and suggestions for the subsequent development of prefabricated residential projects build on upper cover vehicle base in Beijing.
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Experimental Study on the Heat Extraction Effect of Tunnel Exhaust Fans

Wang Chunwang, Li Xiaofeng

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The heat removal effect of a long-term metro line in South China is studied. Through the test section of track tunnel, tunnel, the effect of condenser inlet air temperature of train, the exhaust fan heat removal effect is obtained, the results show that after closing the exhaust fan, the average temperature and daily maximum temperature of the station tunnel are both increased by 0.7℃, the average temperature of the interval tunnel measurement point is increased by 0.8℃, and the daily maximum temperature is increased by 0.9℃. The average air inlet temperature of the condenser at the train stop station in the evening peak is increased by 2.4℃, and the air inlet temperature of the condenser in some stations exceeds 45℃.Though the tunnel temperature still meet the specification requirements, (not exceeding 40℃), but have been unable to guarantee the normal operation of the train air conditioning during the afternoon rush. The opening of the fan has an obvious effect on restraining the temperature rise of the tunnel, especially in ensuring the normal operation of the train air conditioning condenser. The test results show that it is necessary to set up the exhaust system in South China, and provide a reference for the design optimization of the system.
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Research on the correlation between urban subway construction and socio-economic factors

Wang Zhiheng, Li Xiaozhao, Pan Jinli, Lu Minghao, Zhou Shuming, Zhang Changwei

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38 cities that has been opened the subway(by the end of 2019)were selected as the research samples to analyze the status quo of the indicators affecting the declaration of subway, such as GDP, urban resident population, general public financial budget revenue and annual average daily passenger intensity. In addition, the correlation between the subway construction index and the above four socio-economic indicators is analyzed respectively from the horizontal and vertical perspectives. The results show that financial resources and subway operation capacity of some cities are still insufficient, so the scale and pace of subway construction should be controlled reasonably. The density of subway in different cities has a strong linear correlation with its GDP and general public financial budget income. However, taking Beijing as an example, the study finds that the subway construction index in the same city at different periods has a high linear correlation with its GDP, urban resident population and general public financial budget income, and the established multiple linear regression model conforms to this law with a fitting degree of over 99%. The research will provide some reference for each city that should reasonably control the subway construction progress according to their own social and economic level, and promoting the orderly development of urban rail transit.
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Application of 5G communication technology in the train-ground wireless communication system dedicated to urban rail transit

PU Yuyuan

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The main services carried by WLAN (Wireless Local Area Network) and 4G LTE-M (Long Term Evolution for Metro) dedicated to urban rail systems are Summarized; the network structure that the LTE-M system integrated carried train operation control, image monitoring and trunking dispatching is put forward. The current application of 5G technology in urban rail transits is analyzed, the deployment of 5G in train-to-ground wireless communications systems is discussed according to the needs of services in urban rail and network project is designed. At last the relevant solutions and means for the main problems in the process are proposed. .
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Study on space design and natural light introduction of shallow end Hall Station

yanyang

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The subway stations are mostly underground structures, and the ventilation and lighting modes of the stations are mechanical ventilation and artificial lighting. At the same time, the civil engineering investment of the stations with all underground structure is relatively large, and the construction of elevated stations and ground stations will have a certain impact on the regional traffic and regional landscape of the city. This paper analyzes the research background, space design, natural light introduction, fine design scheme and actual operation effect of the station construction through the design cases of four "shallow buried and open cut" rail transit stations which have been built and put into operation. Based on the in-depth study on the site applicability, building energy saving, space effect and other aspects of the station type, it is proposed that the station should be set under the roadside green space in combination with the construction of municipal green belt, so as to reduce the relocation of municipal roads and existing pipelines caused by subway construction. Combined with the characteristics of "open excavation" of station civil structure construction, the buried depth of station structure can be reduced, and the investment can be saved At the same time, it improves the height of the station hall, creates a tall and comfortable rear space, and sets the roof skylight to form the natural lighting and ventilation effect of the station hall, which reduces the investment of the station equipment system and the later operation and maintenance cost. This innovative design idea of green energy saving has been applied in the construction of domestic rail transit. It not only realizes the advantages and applicability of "shallow burying" of the station, achieves the effect of operation economy and energy saving of equipment, but also creates a comfortable and healthy riding environment, which provides innovative ideas for the later design of rail transit station.
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Analysis of harmonic Resonance of Urban Transit Power Supply System

SHI DAN

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When the Urban transit power supply system (UTPSS) operates in the power supply mode supported by only one main substation, the power supply cable is long. It can result in the harmonic parameter matching between the ground-to-ground capacitance of the cable and the main transformer leakage inductance which may amplify the background harmonics in the system. Based on a UTPSS resonant accident occurred during the commissioning of the subway of Line 1 in a city, this paper builds a resonant circuit model and analyzes the reason of the harmonic resonance of this UTPSS. More specifically, the resonance is originally generated by 11th background harmonic and amplified by the parallel circuit consisting of the ground-to-ground capacitance of the cable and the main transformer leakage inductance. The analysis result is consistent with the field recorded data. Meanwhile, this paper puts forward several measures to suppress resonance of the UTPSS in subway: calculate the harmonic impedance parameters in the preliminary engineering design stage, strictly limit background harmonics to meet requirements, evaluate converter manufacturing technique, and confirm the filter functions of SVG.
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Practice of fine decoration design of public area of subway station based on

SU Liyong, ZHOU Yi

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In order to make full use of the visual characteristics of BIM (building information modeling) and VR (building information modeling) technology, solve practical problems such as the decoration design and construction management of the first-phase project of Beijing Metro Line 19, the coordination of end points, and collision inspection. , Taking the construction of the Xingong Station public area renovation project of the first phase of the Beijing Metro Line 19 project under construction as an example. In all phases of the project, we coordinated and coordinated the various project participants, and found that BIM and VR technology in the field of engineering Innovatively put forward BIM+VR-based full-specialized decoration design and factory prefabrication and on-site assembly management management ideas, discuss the necessity of the application of this technology, analyze the achievability of this technology, and The management concept of “test before construction” has conducted research on the whole process of decoration design management. It is believed that the application of 3D scanning, BIM and VR technology in decoration design and construction can greatly improve the progress and quality of decoration projects, and provide passengers with a A good riding environment provides a foundation for the later data-based information operation and maintenance management.
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Satistics and analysis of urban rail transit in 2020_{Mei Jianping}_{Zuo Chao}_{Hou Xiufang}_Li_u_G_a_oyuan

HouXiufang

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. By the end of 2020, Chinese mainland 45 cities opened 7969.7km of urban rail transit operation, and completed 17 billion 590 million passenger trips in the whole year. 57 cities completed 628.6 billion yuan of construction investment that year, and the total length of lines under construction is 6797.5 km. A total of 67 urban rail network plans have been approved and publicized. After deducting the length of the lines in operation, the total length of the approved lines under construction is 7085.5km. During the 13th Five Year Plan period, a total of 4351.7km of new lines were added; The total passenger traffic volume is 96.94 billion; The total construction investment is 2627.87 billion yuan; A new round of construction planning or planning adjustment with a total planned investment of 2978.19 billion yuan in 35 cities has been approved; The scale of operation, construction and planning lines and the amount of investment have increased by leaps and bounds, and the urban rail transit has developed rapidly and healthily.
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AFC system of urban rail transit cloud platform based on microservice architecture

zhangyixin, linlei, zhangning, 陆斌, 陆斌

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With the rapid development of technologies such as cloud computing and the Internet of Things, in order to meet the requirements of flatness and robustness, the urban rail transit AFC system needs to adjust the traditional architecture in combination with traditional businesses and new businesses such as multiple payment methods. The cloud platform AFC system came into being. It has the advantages of distributed storage, high availability, intelligent operation and maintenance, and low coupling, which can make up for the defects of traditional AFC architecture and single architecture. Based on the analysis of traditional AFC system business, new Internet payment requirements, monolithic architecture and micro-service architecture comparison, this article considers the use of the micro-service architecture-based cloud platform AFC system, builds a micro-service architecture according to business needs, and modularizes the business The form is presented, and the key technologies under the micro-service architecture are considered. Finally, the compatibility of the micro-service architecture and the existing system is considered to provide references for the application and innovation of micro-services in the AFC system.
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Research on Resilience Evaluation Method for Fully Automatic Operation system Based on Monte Carlo Simulation

Guo ziwei, Yan Fei

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In order to avoid the one sidedness of resilience evaluation for automatic operation system in single fault scenario, Monte Carlo simulation method is used to simulate the randomness of system disturbance and performance degradation, and provide a probability based resilience evaluation method for automatic operation system. Taking Yanfang line as an example, the fault data of signal and integrated supervisory control systems in the past three years are counted, and the fault frequency and fault recovery time distribution of each equipment are calculated. According to the failure consequence of the equipment, the performance degradation of the equipment is classified, and according to the failure data, the probability of each performance degradation level is counted. The "virtual value of state" is set for each performance level to quantify. The weight of the output data stream of the device is the same as the "virtual value of state" of the device. The fluctuation of the system performance is represented by the change of the weight of the total data stream of the system. Using the "Zobel" resilience quantization method, after 100000 simulation, the estimated value of the system resilience is 0.9893. At the same time, 100000 perturbation simulations were carried out for each device, and the resilience probability cumulative distribution of the system for each device was obtained. The results show that the resilience distribution of the system is wide when CI, ATP and ZC are disturbed, and the system resilience may appear low value when the switch machine and track circuit are disturbed, the system resilience is relatively stable, and the system resilience remains above 0.97.
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The construction and application of the integrated system of internal and external industry of rail transit engineering survey

ZHU Xia, MAQuanming, TANGChao, HUXiaofei, XINGLijun, LIFangning

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In order to solve the problems existing in the traditional field work of rail transit engineering survey, such as heavy workload of paper record of field description data, high error rate of manual input data, data barrier and information island between various links of survey and production, a kind of engineering investigation and field work integration with GIS, CAD computer graphics, data synchronization, word online editing and so on is developed Chemical system. The system realizes the whole process integrated management from survey outline, field collection, soil test, interior work arrangement, result audit and data archiving, which improves the operation efficiency of survey professional production and the owner"s information application management level of survey results. The system has been applied in many urban rail transit engineering survey projects in China, and has achieved good results The integration of internal and external management of enterprises and informatization supervision of quality supervision departments provide new ideas.
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Optimization of Urban Rail Transit Scheme Considering on Vehicle Load Factor

ZHANG Hanxiao, LIU Yuran, LIU Xu

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It was gloomy with the unexpected epidemic in 2020. For urban rail transit operation, it is important to ensure passenger travel gap safety and transportation orderly, when making overall plans with the epidemic prevention and the fast-growing passenger of work resumption. This paper focuses on equalizing the vehicle load factor. It has analyzed the characteristics of the time-space distribution of the passenger travel and has broken the existing resource allocation constraints. The optimization of the urban rail transit scheme is configured by the unbalanced organization, multiple routes, and so on. The networking scheme is good for mollifying the contradictions between capacity and travel needs. It also provides a practical experience on reducing train congestion, improving travel efficiency and reducing operating costs.
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Application of LiFePO4 battery in Urban Rail Transit

Dai Wei, Zhang Bin

Abstract: (33) HTML (0) PDF (0.00 ByteKB) (0)

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through the comparison of the application of LiFePO4 battery and VRLA battery in urban rail transit, com-bined with the transformation of Beijing Metro Line 8 to integrate ups and DC panel, the actual operation effect of using high safety floating protection LiFePO4 battery to replace the original VRLA battery is analyzed, which provides a new way for the selec-tion of urban rail transit battery.
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Research on the Design of Fully Automatic Driving Metro Depot Based on BIM Technology

NAO Jiacairang, CHENG Zhongguo, ZONG Chao, BA Wenbo

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The design of metro depot has the characteristics of large engineering volume, multi-specialty and complicated professional interfaces. It is easy to have design defects and collision problems when using traditional design methods. In order to improve the design quality, we have explored the application of BIM technology in ZhuaMaShan metro Depot Project. We use Autodesk software and a variety of BIM design tools which are independently developed by us in the project to complete the BIM design work involving 15 professional contents. By the process of establishing family library, BIM design of various major and model integration. The BIM model construction of the entire metro depot has been completed. The applications of design scheme comparison, engineering quantity statistics, collision detection, BIM+VR display and other applications are realized. Providing a strong guarantee for improving the design quality.
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The Key Technology Research on the Top-down Construction Method for Bored Super-large Section Tunnel that Based on the Arch-cover Method in Soft Rock Area

ZOU GUANG JIONG, PENG HUI, ZHOU JIE

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The top-down construction method for bored super-large section tunnel based on the arch-cover method learns from the concept of top-down method used in open-cut structure constructions, which applies double-side-drift method or other section excavation method to excavate and complete the arch cover secondary lining. After the arch cover finished, the meddle and bottom of the tunnel section will use combined temporary and permanent supports, reasonable construction organization and cover and cut-bottom up method to reduce the engineering risk and difficulty. At the construction phase of the meddle and bottom of the tunnel section, the construction organization will develop in 3 dimensions. It will offer enough space for the tunnel construction. Now, this construction method has been successfully applied on Minan Avenue station in Chongqing rail transit loop line. Through this project application, it proofed this construction method can reduce the engineering risk and difficulty, enhance the construction efficiency, cut-down the project funding and shorten the construction period.
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Research on Thermal Environment of Metro Carriage Based on Human Thermal Regulation Model

LIU Haijun, WU Yang, PENG Xingzhi, GUO Hang

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Nowadays, the research on the thermal environment of subway carriage often sets the boundary of the human body to a constant heat flow, which cannot reflect the interaction between human thermal regulation and the environment, and it is difficult to accurately evaluate the thermal comfort of the carriage environment. In order to effectively analyze the thermal comfort of the carriage environment, a 57 multi-node human thermal regulation model coupled with the carriage thermal environment is proposed to simulate the thermal comfort of the carriage environment of Beijing Metro Line 15. In addition, this method is used to study the thermal environment and passenger thermal comfort in the air-supply grille carriage of the three working conditions, and it is concluded that the temperature and speed in the carriage of the working condition 1 are evenly distributed, and the passengers have better thermal comfort. Compared with the constant thermal human body boundary conditions, this method can more comprehensively analyze the thermal comfort of passengers, and has certain reference significance for improving the actual thermal environment in the carriage.
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Research on MIMO characteristics of keyhole effect in subway tunnel

liuxi

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This paper studies the influence of keyhole effect on multiple-input–multiple-output (MIMO) performance by using double leaky coaxial cables (LCXs) and a single LCX in tunnel scenario. The keyhole effect in the slots of LCX was theoretically studied. Then, a 2×2 MIMO measurement campaign using LCXs at 1.8 GHz in a rectangle tunnel and an arched tunnel were carried out. The measured results reveal that the keyhole effect does not exist in double LCXs case, and meanwhile the keyhole probability in single LCX case is also limited. Finally, the results of channel capacity in double LCXs case and single LCX case are provided. These results can provide a prospective guidance for employing MIMO technology in tunnels.
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Research on passenger flow forecast of Suzhou rail transit during holidays

LIU Weiyuan, Ge Yuechun, LI Lei, YIN Yan

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Large passenger flow on holidays often brings great pressure on urban rail operation and management. Timely and accurate prediction of passenger flow during holidays can provide an important basis for urban rail transit operation and management departments to formulate transportation plans and determine countermeasures, so as to ensure the safe and smooth operation of rail transit during holidays. Based on the analysis of the change trend of passenger flow in holidays, the paper obtains the benchmark passenger flow by historical passenger flow trend, and constructs arima-garch model based on the current passenger flow level to predict the passenger flow of rail transit in different periods of holidays in the future. Based on the historical passenger flow data of Suzhou rail transit in 2018 and 2019, the method is verified and analyzed. The results show that: the method can effectively identify the characteristics of passenger flow on holidays, reduce the preliminary work of passenger flow forecast, and realize the passenger flow forecast of urban rail transit in different periods of holidays.
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Study on control limit value of cross section deformation of shield tunnel structures with staggered joints

She Caigao, Zhang Cun, Wang Huaidong, Tian Zhiyao

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Excessive deformation and serious diseases have occurred on some shield tunnel structures in soft soil area. These shield tunnel structures in service with defects will still be in service for a long time, and they will still face various adverse service environments in the subsequent service period. Therefore, it is necessary to put forward the control limit of shield tunnel structure deformation, which can provide judgment and decision-making basis for the maintenance and operation of the structure in time when the structural deformation of the tunnel develops further. Based on the background of three subway sections in Nanjing, this paper explores the correlation between cross-sectional convergence deformation and various diseases of staggered seam assembled shield tunnel by means of measured data analysis and three-dimensional refined finite element simulation. The two methods verify and complement each other. The results show that the service performance of tunnel structure is good when the convergence deformation is less than 30 mm. The water leakage and cracks appear and the bolts begin to yield when the convergence deformation is 30-60 mm. The disease intensifies and the segment is damaged when reaches 60-80 mm., The first bolt reaches the tensile limit state and the safety is greatly threatened when reaches 80-100 mm. The whole ring structure is on the verge of yield when more than 100 m. On the basis of structural performance degradation characteristics the control limit of cross section deformation of shield tunnel is proposed.
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Aseismic analysis and measures of shield tunnel in liquefiable soil

SUN Xibo, ZHONG Yi, WAN Xiaofei, HAN Yafei, ZHANG Xiaowei

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The deformation and internal force of shield tunnel in saturated sandy soil layer may be changed due to liquefaction, which may lead to tunnel failure. However, the influence of liquefied strata on overlapped tunnel may be aggravated by the interaction between structures.Based on engineering example, a three-dimensional model was established by using the software Midas GTS to analyze horizontal and vertical seismic dynamic time history of the tunnel with liquefiable soil. It analyzed the different influences of different positions and uneven distribution of liquefied strata on the tunnel. The internal force and deformation of the tunnel structure in liquefiable and non liquefiable conditions were compared. The treatment effect of stratum reinforcement on liquefied stratum is studied. The internal force and deformation of the tunnel in liquefiable condition are increased to a certain extent. It cause a great impact when the liquefied strata are located at the bottom of the tunnel, or it is not uniform. The vertical seismic action mainly affects the vertical deformation of the tunnel. it is better to use radial grouting to reinforce the ground when the liquefaction degree is moderate.
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Research on Revenue and Expenditure Characteristics of Urban Rail Transit Operation

LIU Liqin, XING Yanting, LI Mingyang, LI Xin

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In recent years, China's urban rail transit has developed rapidly and its operation scale has maintained a rapid growth. Rail transit not only has a large initial construction investment, but also has a great pressure on expenditure in the operation period. During the period of the 14th five-year plan, how to realize the development of urban rail transit from having to high quality and realizing the sustainable operation economy is an important problem that cities need to study and solve. This paper analyzes the operation cost, ticket revenue and non ticket revenue of rail transit in 13 typical cities in China, summarizes the characteristics of operation revenue and expenditure, and conducts benchmarking analysis based on the operating revenue and expenditure of Tokyo Metro and Hong Kong Metro. Based on the advanced experience, the key to the sustainable development of urban rail transit operation economy is to "open up sources and reduce expenditure", effectively reduce the operation cost, improve operation service level to attract passenger flow, vigorously develop related business, and realize the internalization of external benefits. Hoping to provide beneficial help for the development of urban rail transit.
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Research on the Improvement of Existing Metro Stations Based on the Concept of Micro-center

FENG Xipei, LI Zehui, WANG Hongyang, XU Ning

Abstract: (113) HTML (0) PDF (0.00 ByteKB) (0)

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With the development of the city and the change of the characteristics of passenger flow, new problems have arisen in the station operation and travel, and conventional expansion and reconstruction cannot meet the new needs. Therefore, with the help of Tokyo's experience in the reconstruction of existing lines, Beijing puts forward the concept of "micro-center", and classifies the stations according to their location positioning, planning conditions, passenger flow characteristics, existing environment and other characteristics. Based on line 13 wudaokou station as an example, according to the subordinate type, "center" to upgrade to the station and urban renewal as the core, adopts the design idea and strategy of update, on the station and surrounding city overall planning and design, to realize the organic integration of rail transit site and the urban space, the implementation of convenient transport interchange integration, optimization of regional traffic organization, the integration of urban landscape, raising the level of service in the station, provide a reference for the upgrading and reconstruction of other existing rail transit stations.
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Research on quantitative method based on transfer passenger flow control of Urban Rail Transit

Jia Shuanhang, Lu Jian Hong, Liu Ming Ming

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The transfer station of urban rail transit has the characteristics of complex passenger flow structure, rapid passenger flow growth, limited station capacity and bottlenecks on passenger flow paths. In view of the difficulty and high risk of passenger flow organization at transfer stations, this paper proposes the concept of passenger flow control group of transfer station. Based on the principle of flow balance and the calculation method of transport capacity matching, this paper proposes the method of passenger flow control at transfer stations, that is, considering the source of transfer passenger flow, through the passenger flow pressure sharing of line network, the accurate control of passenger flow at the transfer station and time can be realized, and the accurate and scientific passenger flow control at the transfer station can be realized, so as to improve the transport service quality of the transfer station and reduce the operation risk of the station. In the case of predictable large passenger flow at transfer station, the paper describes the quantitative control strategy and calculation process of passenger flow in detail, and formulates an effective plan and risk assessment mechanism to ensure the safety and order of large passenger flow at transfer station.
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Application, Development and Suggestions for Technical Improvement of Segmental Precast Bridge Technology in Guangzhou Metro

阳发金, Sun Junling

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Since 2003, segmental precast bridge technology was adopted in Guangzhou Metro Line 4, line 6, line 14 and line 21. The segmental precast simply supported beam in the initial application stage has gradually developed into continuous rigid frame. In order to promote the further development of segmental precast bridge technology and take advantages of segmental precast continuous rigid frame，the application and development of segmental precast bridge technology in Guangzhou Metro are summarized in this paper; the comparison and analysis of segmental precast simply supported beam and continuous rigid frame are carried out, the latter can save the total cost in construction period and maintenance cost of bridge bearings in operation period; and suggestions for technical improvement are put forward: the span of standard section bridge should be unified as far as possible, the whole bridge precast of superstructures and substructures, the internal and external prestressed mixed tendons, the reusable temporary prestressed tensioning pedestal, the precast and erection of No.0 segment of main beam on pier top and no support construction of the whole bridge, which can further improve the comprehensive economic benefits.
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Research and Application Analysis of Escalator Condition Monitoring and Early Warning System Based on Vibration Analysis

zhangyi, lixin

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Escalators are special equipment, and their safety is closely related to the personal safety of passengers. Escalator status monitoring and early warning is a predictive system to ensure the safety of escalators. The system is composed of sensors, data collectors and data analysis software. It adopts the principle of vibration analysis to realize fault warning and maintenance component guidance to prevent faults or accidents. happened. The system has been used in the Beijing MTR project. Through the analysis of typical cases in the project, the application and operation mode of the system are explained in detail, and combined with the use of Beijing MTR Line 6 and Daxing Airport Line, the use of vibration is verified. Analyze the effectiveness of the escalator condition monitoring and early warning system and its significance in actual engineering.
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Simulation research on Passenger flow evacuation in rail transit station based on BIM-VR

BAI Han, YANG Shuai, FENG Xvjie, SONG Xiaomin, DONG Shoufang

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Urban rail transit is an important mode of public transportation in many large and medium-sized cities. Existing researches on pedestrian models mainly adopt micro-simulation methods. This research is based on widely used building information Model (BIM) technology, virtual reality (VR) technology and Agent model to realize high-reality pedestrian emergency evacuation simulation, and develops VR evacuation simulation system by integrating research results. In this study, THE Revit software tool is used to carry out BIM modeling, and the completed BIM model is loaded into VR engine Unity3D, so as to complete the docking between BIM and VR in Unity, realize the docking of external VR equipment, provide technical support for the rapid VR of BIM model, and save the modeling workload. Through the comparative analysis of relevant domestic and foreign specifications, virtual fire scenarios are realized in VR scenes and different fire conditions and modes are set. Classification and parameter assignment of pedestrians are carried out, and C# programming and the principle of finite state machine are used to realize the Agent's independent state switching and corresponding behaviors according to environmental conditions. The VR evacuation simulation system is developed, and the system case application is carried out aiming at the practical engineering problems. The study combines the advantages of BIM and VR technology, and combines the Agent model to build a more realistic pedestrian evacuation simulation. The DEVELOPED VR system can also play its value in the field of scientific research and engineering application.
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Research on Train Position Estimation in CBTC System

zhaopeng, gengpeng

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In the signal system of urban rail transit, in order to ensure the safety of train services, ZC estimates the occupation position of non-communication train at the cost of accuracy after the train running in CBTC level is degraded, it takes the axle counter as the unit to judge the occupation position of non-communication train, and takes the idle axle counter on both sides of the occupied axle counter as the possible occupation range of non-communication train. This paper improves the scheme and proposes a new method to judge the train occupation position based on the integration of ZC and CI equipment. It realizes the fine management of the train occupation position and improves the accuracy of the train occupation position, so it can meet the application requirements of the line with smaller interval and higher speed under the CBTC mixed running mode. At the same time, it can improve the accuracy of judging the failure of axle counter equipment. In brief, this paper has some reference value for improving the reliability and availability of CBTC system.
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Exploration and Application of Green Subway Technologies in Line 1 of Jinan Rail Transit

Liu Haidong, Wang Lin, Pan Lei

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Jinan rail transit takes "green subway" as the construction concept, and has adopted nearly 40 technical measures to save energy, land, water, materials and environment. This paper mainly takes Line 1 as an example to introduce in detail the land saving technologies such as equipment housing under the elevated station and resource sharing of the main substation, which can save about 28,000 square meters of land. The construction technology of exposed concrete in the elevated station, the prefabricated composite structure system and other material saving technologies can save 30 million yuan and 43% of the concrete usage. By adopting energy-saving technologies such as adjustable ventilated platform door system, each station can save about 1 million yuan of electricity per year. Using photovoltaic power generation on elevated platforms, amorphous alloy distribution transformers, renewable energy absorption and other technologies, it can save 7.7403 million kilowatt-hours of electricity per year. It is expected to provide reference for the construction of Jinan railway line and other urban rail transit.
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Review and re-innovation of investment and financing mode of Shenzhen rail transit

Gong Wenping, Tian Xin

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Shenzhen rail transit has entered a period of high-quality development, the financial pressure of the government is increasing, it is necessary to innovate the investment and financing mode again. Shenzhen rail transit have experienced a unitary and diversified innovation in investment and financing, the fifth phase will implement the idea of integrated development of rail and land, and the development of railway integrated property is the cornerstone of rail transit investment and financing re-innovation. Based on the opportunity that Shenzhen should make use of the pilot and leading demonstration policies, the author puts forward two innovative investment and financing modes: the innovation point of "rail transit PPP projects + railway integrated property planning + floating cash subsidy" is that the PPP company should do a good job in railway integrated property planning based on TOD concept. The government auctions the land and obtains the land price in full according to the planning scheme, compensates the PPP company according to the floating proportion specified in the agreement, and the PPP company maximizes the floating cash subsidy through the planning of the railway integrated property; the innovation point of "joint bidding of rail transit PPP projects and railway integrated property development" is that the rail PPP and railway integrated property are joint bidding as the same project, and the land price can offset the cost of rail construction, reduce the central and local expenses of land revenue, and realize the optimal combination of rail construction cost and land price. The PPP company can obtain value-added income through the development of railway integrated property to feed the rail construction and operation, the property development also attracts patronage. The government and enterprises can achieve a win-win situation.
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Discussion on Chongqing multi standard rail transit coordinated command center

Nan Chen

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With the acceleration of urban agglomeration construction process, rail transit construction presents the trend of multi-mode and network development, and multi-mode traffic cooperative command system is the key of multi-mode traffic cooperative transportation. This paper proposes to break the traditional closed information service mode, operation organization mode and emergency command system among various modes of rail transit, and build a new system based on rail express line, rail common line and urban (suburban) railway It is a comprehensive supervision and management platform for the integration of multi-mode rail transit, and puts forward applicable construction schemes from the aspects of management system, overall positioning, system architecture, main functions, support system, etc., so as to give full play to the comparative advantages and combined effects of different modes of rail transit, improve the comprehensive transportation efficiency, collaborative disposal ability and passenger travel sense of multi-mode rail transit, and provide reference for the current situation The network operation plays a supporting and improving role, and provides a reference for the subsequent construction of multi standard rail transit coordinated command center.
1
beijing

YU Songwei, chengyan, hepeng, zhoumin, hu yingyue

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Oriented at the aim and existing problem, this paper starts from the strategy and complexity of internal urban rail transit, explaining the substitution of traditional engineering thinking and the effectiveness of using new system thinking to solve problems. The realization of the sustainable development of urban rail transit and the necessity of creating a new cross-discipline "Metro Science" were proposed for the first time. A comprehensive analysis using the "three factors" method was carried out on the feasibility of creating metro science. Finally, the knowledge system and creation path of metro science were put forward preliminary. The research methods of urban rail transit and metro science methodology are implemented through this paper consistently.
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Research on the Effect of Stiffness Change of Vibration-absorbing Pad on the Vibration and Structural Noise of U-shaped Girder Bridge

HU　Chuan, ZHONG Rui, WU Xue, KONG Xiaoyu

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In order to study the effect of the vertical stiffness of the isolation damping pad on the vibration and noise of the U-beam bridge,a vehicle-track-bridge rigid-flexible coupling based on the Timoshenko beam model was established based on the multi-body dynamics and finite element joint simulation principle. The dynamic model and the theoretical calculation results ware compared with the previous literature to verify the validity of the model. The model was used to calculate the vibration and noise of the bridge system when the damping pads had different vertical stiffness values. The results show that with the increase of the vertical stiffness of the isolated damping pad, the vibration response of the rail and rail plate decreases, while the vibration response of the bridge structure is magnified, and the vibration amplitude of the track structure and U-shaped bridge changes obviously, and then gradually tends to smooth. The increase of vertical stiffness of isolated damping pad will increase the secondary noise of bridge structure, so the damping pad with smaller stiffness should be selected to suppress the secondary noise of U-shaped beam bridge, but too small vertical stiffness may amplify the structural noise in the low frequency area within 40Hz. Based on the calculation results of vibration and structural noise of U-shaped beam bridge system, taking into account the engineering cost, the vertical stiffness of isolated damping pad used in viaduct structure is 0.067N/mm³.
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Optimized application of assembly track technology in Suzhou Metro

WANG Zhan-sheng, CHEN Peng, XUSHOUWEI, zhaibeibei, daibiao

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On the basis of summarizing the application status and existing problems of slab track in urban rail transit, this paper expounds the core technical concept of prefabricated track and its optimization application technical points under the typical working conditions of Suzhou Metro Line 5, including the main technical parameters determined according to the engineering conditions, steel fiber reinforced fine aggregate concrete filling layer, spray type isolation layer and other technologies adopted for the first time in China And the construction technology optimized based on the third generation of precast slab fine adjustment equipment and measurement and control system technology. The application results show that the technology has many advantages, such as less construction procedures, high construction efficiency and good track smoothness. It provides a reference for the further application of prefabricated track technology.
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The three-sphere Integrated frame and Nine Design Concepts of Environment-friendly Urban Rail Transit Station

GAO guofei, ZHENG han

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The design of urban rail transit station should not only meet the basic travel needs of passengers, but also respond to the needs of environment-friendly city construction. Firstly, the concept of environment-friendly station is put forward. Then, taking the main building of the station and the organization of passenger transport as the core, the evaluation theory of environment-friendly urban rail transit station is put forward with the extension of people-oriented transportation, green environmental protection, energy saving and consumption reduction. Then, combined with the development needs of urban rail transit, nine design concepts of environment-friendly stations are proposed. Finally, the paper clarifies the design key points of environment-friendly station, studies the weight of each design key points, and evaluates the importance of nine design concepts. This paper puts forward some suggestions on environment-friendly design and construction of urban rail stations in China. The research results can support the comprehensive evaluation of environment-friendly rail transit stations and guide the design of rail transit stations at the theoretical level. Thus, the location advantage of rail transit in public transportation can be enhanced, and the integration of station design and environment can be further promoted.
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Analysis and Enlightenment on the Characteristics of Rail Transit Through Operation in Tokyo

HE Peng

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Based on the systematic analysis of the rail transit through operation in Tokyo Metropolitan Area, the interoperability of the through operation and seven groups of through operation combinations are obtained. Secondly, the relationship between the through operation lines and the urban development are analyzed from two aspects: urban functional zoning and urban spatial structure. Then, by studying the capacity characteristics of the through operation sections of the rail transit network in the early peak period, and taking the Keio-Shinju Line as an example, the organization modes and fundamental laws of through operation and express/local train are analyzed. Finally, the enlightenments and suggestions on the development of China's rail transit are obtained.
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Suggestions on Function and Action Improvement of DC Frame Protection

ZHANG Kaibo

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In view of the great influence on the normal operation of the project after the action of DC frame protection, analysis of its function configuration and action characteristics, from the perspective of avoiding device misoperation, puts forward the suggestion of setting multi section protection and judging the current direction for current frame protection; from the perspective of protection action characteristics，suggestion of setting rail potential limiting device in depot traction substation to cooperate with frame protection; the installation mode of on-line isolation (or combination) switch cabinet and its cooperation with frame protection, analyzes and puts forward some suggestions, ensure the long-term safe and reliable operation of the project.
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Analysis on Dalian Urban Rail Transit Operation and Optimization Strategy of Public Transport

XU Chengyong, HUANG Xin, LI Tianshi, Hu Jinbao, Su Lina

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According to status of urban traffic development, the paper evaluated the urban rail transit operation performance in Dalian and pointed out the following problems: vicious competition between rail transit and conventional public transit, high ticket price, construction lagging of new line, mismatch between operation lines and city development, low passenger flow in suburban line, insufficient land development. Optimization strategies are put forward in different terms. Dalian should accelerated the transformation of traditional industries and increase urban vitality. The research on ticket system and preferential measures should be conducted. Conventional public transit network might be optimize and the study on combining urban transit operator and bus operator. Acceleration of new line construction is necessary to improve urban network and new lines matched with city development should be planed. The supervisory and management of land use should be strengthen to encourage high-density development and ensure development time.
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Research on Capacity Loss in the Mode of Express/Slow Urban Rail Transit Based on Train Evenness

SHI Xiulu

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As one of the main methods to meet the needs of rapid and efficient of urban rail lines, the express/slow train organization mode was very important. But the calculation principle and formula about system capacity loss had some errors. In order to improve the calculation accuracy and application range, the corresponding relationship between departure uniformity and capacity loss was described by introducing uniformity parameter. The capacity loss formula under the mode of slow and fast had summarized and optimized with the premise of uniformity. The accuracy and reliability of the formula were verified by running chart. The main conclusions are as follows：(1)The existing capacity loss formula is based on the principle of capacity maximization, and the uniformity of express trains is not considered in the calculation process, which is quite different from the actual layout results;(2)When the number of fast trains (or slow trains) is constant, the system capacity decreases first and then increases with the evenness; when the evenness is constant, the system capacity decreases with the fast trains (or slow trains) increase;(3)The system capacity loss formula is put forward when the slow train is dominant and the fast train is dominant with the premise of evenness;(4)The optimized capacity loss formula significantly improves the calculation accuracy and application range, which can provide reference for related projects.
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Theoretical Study About Utility Tunnel in Base for the Vehicle of Urban Rail Transit

WEI Sheng, QIN Yi

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The layout design of the outdoor pipelines is a key and tough job for construction of the base for the vehicle of urban rail transit. The outdoor pipelines are always directly buried underground. But there are some problems with this approach in the stage of design, construction, operation and maintenance. Therefore, the installation of the utility tunnel provide an idea for solving this existing problems. Aiming at this related problems, the necessity and significance of setting up outdoor utility tunnel are described. The paper introduced the theoretical study about utility tunnel from many aspects, including the analysis of the type of pipelines, the layout principle of utility tunnel, the design of section, the design of special node and the auxiliary engineering of utility tunnel.
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Research on Influential Parameters of Ventilation and Air-conditioning Energy Model for Subway Stations Using Sensitivity Analysis

HUANG Li, LI Xiaofeng, SU Ziyi

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With the continuous expansion of subway scale and energy consumption, energy-saving of ventilation and air-conditioning (VAC) systems in subway stations has gradually become a research focus. In this paper, influential parameters of the VAC energy model in subway stations are identified and ranked, using three commonly-used sensitivity analysis methods (regression-based, screening-based and variance-based). Results show that the top 25% ranked parameters identified by the three methods are the same, but the orders are different. Among the three sensitivity analysis methods, the rankings of variance- and screening-based method are basically the same, whereas the ranking of regression-based method is quite different from the previous two. Besides, the regression method is the most efficiency one in consideration of the computational cost, the calculation time of variance- and screening-based method are 25 times and 3 times, respectively. By comparison, it can be concluded that the screening-based method performs best in consideration of the parameter ranking and computational cost. Furthermore, the quantitative influence of the above-mentioned important parameters on the energy consumed by VAC system in a typical island subway station were studied. Results show that the impact of outdoor air parameters on is as high as 84%; the effects of mechanical fresh air volume, air infiltration volume through the entrances and air infiltration volume through the platform screen doors are 43%, 29% and 12%, respectively; the impact of equipment efficiency reaches 39% and is non-linear; the influence of the air parameters inside the station and the tunnel are 37% and 33%, respectively. The outcome of this research points out important variables that need to be paid attention to in the energy conservation design and operation of subway stations, providing guidance for energy-saving operation and management of stations.
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Application optimization of subway sewage lifting system based on cam pump technology

lixiao

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Based on the application of traditional sewage pool + sewage pump technology, conventional closed water tank sewage lifting technology and vacuum sewage lifting technology in subway station, this paper systematically studies and analyzes the sewage lifting technology based on cam pump in combination with the operation demand, starting from solving the problems of pain points (such as poor sanitary conditions and high cleaning cost), with low maintenance and high reliability（Such as high suction head, bottom cleaning, double level sensor control and intelligent) as the goal, the subway sewage lifting technology based on cam pump technology can solve the problem of bottom cleaning of sewage pool, improve the operation and maintenance conditions, reduce the difficulty and intensity of operation and maintenance, and the overall operation effect is good. At the same time, suggestions for further optimization and application are also given.
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Study of Predicting-Model for Interval Tunnel Temperature in Subway

ZHANG Yue, LI Xiaofeng

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The over-temperature situation happened in summer will result in high-pressure failure in subway trains, so the highest tunnel temperature is an essential factor for safe operation. In this study, simulation method was adopted in factor-analysis. The three influencing factors concerning internal heat generation (passenger number, carriage weight, and Regenerative Braking System (RBS) efficiency), and two factors concerning transmission load (soil conductivity and thermal capacity) were analyzed. Based on a serial of orthogonal experiments, a Response Surface Model (RSM) of the subway tunnel temperature was established. This model provide a quick way of predicting subway tunnel temperature in different situations, which could be helpful in both design and operation stages in subway without complex and time-consuming simulations.
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Thoughts on Interactive Integrated Design of Subway Station

wangweixing

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With the goal of improving the quality of subway construction in China，Combined with the change of subway development demand in the new era, this paper discusses the problems of poor interaction of multiple planning, relatively closed subway design system and neglect of passengers' experience demand in traditional engineering design methods in China's subway design in terms of the relationship between urban planning system and the present situation of design techniques。Based on the experience of subway design at home and abroad, this paper puts forward an interactive integrated design method of subway stations, emphasizing the whole-process interaction with urban planning system, the cross-border integration and interaction of various specialties in the design system, and the interaction with passengers' experience, which provides certain reference significance for promoting the high integration of subway and city and providing better services for the city.
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Research on TOD Planning and Design Theory

CUI Xu, LIANG Pengpeng, YU Bingjie, CHEN Binglang

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At present, one of the main functions of rail transit stations is to transport passengers. The construction of rail transit networks promotes the large flow of population, and at the same time produces multi-space scale effects. TOD can meet the diversified functional needs, stimulate the vitality of the city in the affected area, and coor-dinate with the construction of the transit metropolis. Theoretical and practical values of TOD are becoming more prominent. However, the current TOD-related research results are mainly discussed on a single scale, which lacks systematic, multi-scale and multi-dimensional combing. Based on this, the paper analyzes the evolution of TOD theory through the bibliometric method, studies the comprehensive effect of stations under the influence of new urbanism, the effect of agglomeration of stations under the influence of smart growth, the effect of station group structure in the multi-dimensional era, and explores the theoretical connotation of TOD planning and design in different development stages. Comparing the differences of TOD concepts between China and the United States, it is found that the overall density of Chinese cities is high, the density distribution is homogeneous, the commuting time in big cities is long, and the problem of mismatch between job and residence is prominent. In view of the current problems in China, this paper puts forward the development suggestions and strategies of TOD fine design, collaborative planning and space-time interaction from the scale of station, station area and station group, hoping to provide reference for future TOD planning and design.
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The Innovation mode of Integrated Development Project of Suzhou Street Station of Beijing Subway

WANG Yao

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Urban rail transit has been developing rapidly in China. TOD development mode has further led the wave of integrated development of rail transit over recent years, creating a number of urban rail micro centers with intensive land, diversified functions and convenient environment, which fully illustrated the concept of "Rail transit leads the city development". Based on the rail transit integration project of Suzhou Street Station in Haidian District of Beijing, this paper analyzed five types of issues ahead of it: site, mode, function, construction period and fund. The innovation mode of rail transit integrated development has been researched and proposed to combines several lands and achieve multiple functions, which coordinates and utilizes the relevant policies such as "one-off bidding" of shantytown reconstruction. The project effectively promoted the subway construction, solved historical problems, saved subway investment and met the needs of residents. It has achieved remarkable results in economy, society and practice, reaching a win-win situation for the government, enterprises and citizens, which can provide reference for the subsequent construction of similar rail transit projects.
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New York Subway Financial Dilemma and Its Enlightenment to the Sustainable Development of China's Rail Transit

liuxiaodong, daili, zhouguohua, zhoufangting

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In the development of rail transit, sustainable development has become the key issue. Based on the development and current situation of the New York metro, summarize the main problems, use case analysis, and comparative research method to clarify the inner relationship between financing, facility upgrades, and transportation service quality. Identify the huge funding gap is the key reason. In response to the financial dilemma of the New York subway, based on the two dimensions of government subsidies and operating economy, the reasons for the dilemma faced by it are from four aspects: incorrect development positioning in the early stage of development, unclear division of two-level government powers and responsibilities, stagnant daily operating income, and insufficient premium recovery. It is proposed that China’s rail transit should absorb the lessons of the New York subway in the development process, strive to realize the internalization of the positive externalities of the "government subsidy + diversified development" two-wheel drive, clearly divide the responsibilities of all parties involved, and explore the construction based on "tax + development" Driven multiple premium recycling models to achieve high quality and sustainable development.
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Study on Deformation Control Technology of Shield Tunnelling Underpassing Dense Buildings Based on Soil Pressure Balance Model

LIU Anwei, LI Zhaoping, LI Yang, LI Ming

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The shield tunneling method is adopted in the section between Laodonglu Station and Wanghuatun Station of Shenyang Metro Line 4, and the stratum through which the tunnel passes is the water-rich clay stratum. In the curve section, the tunnel passes through dense buildings, and the deformation control standard of the buildings is high. According to the comparison of the tunneling effect of the two modes, the soil pressure balance mode is proposed to pass through the buildings. In this paper, the parameters of shield tunneling, the setting of soil pressure, the setting of grouting hole of B-type pipe slice and the measurement and control technology of curve section are discussed in detail, and the synchronous grouting grout suitable for the characteristics of formation and the characteristics of shield structure and the gap filling grout between the excavation contour of knife disk and the outer edge of shield are developed. The result of building deformation monitoring shows that the uplift and subsidence deformation are within the allowable range, which greatly improves the tunneling efficiency of shield.
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Study on route planning of passengers connecting urban rail transit from urban external transport hub

CHI Jushang, HE Shiwei

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The existence of urban external hub ensures the interconnection of urban internal and external transportation, a large number of passengers choose to transfer to rail transit at the external transport hub to enter the city. Passengers who enter the city usually carry more luggages, which requires higher comfort than commuters. To study the passenger route planning based on rail transit and supplemented by other public transport modes can reduce pressure on road network and improve passenger comfort and further attract passenger flow by "avoiding" congested sections and adjusting transportation. This paper uses web crawler method to obtain the running time and cost of urban rail transit from Beijing Daxing International Airport to Beijing from open data sources, and analyzes the accessibility and advantages and disadvantages of Beijing rail transit network compared with riding. Based on the above results, this paper designs a generalized cost considering congestion and other factors for connecting urban rail transit passengers. On the basis of the generalized cost, a passenger route planning algorithm to solve the shortest path by dividing sub networks was designed. Compared with the route provided by the existing route planning system, it is proved that the algorithm in this paper can provide more comfortable travel route for passengers.
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Research on urban rail transit planning strategy based on mobile phone big data

陈锋

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Traffic demand analysis and prediction is an important basis for urban rail transit planning. To compensate for the uncertainty of traffic demand and ridership prediction, this study takes Shijiazhuang as an example, uses mobile phone big data to analyze urban characteristics from the four dimensions of job-housing distribution, job-housing balance, travel demand, and commuting circle, makes up for the deficiency of demand prediction model from the four aspects of urban feature description, current traffic model verification, development trend evaluation, compares with le-de-France, draws on the experience of rail transit planning and development in le-de-France,and provides decision-making reference for the urban rail transit planning.
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Analysis on the Key Characteristics of French Modern Tramways

YANG Zhicheng, Peng Hao

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French modern tramways have large construction scale and mature operation mode. Different urban tramway systems have their own characteristics, forming a variety of urban samples. Combined with the development process of modern tramways in France, this paper analyzes the distribution, system mode, operation scale and construction plan by statistical analysis method. This paper summarizes the characteristics of wiring, depot scheme and network operation in the design and operation, so as to provide reference for the follow-up planning and construction of modern tramways. Finally, using the experience of France for reference, this paper puts forward some suggestions on the problems existing in the development of modern tramways in China.
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Statistical Analysis of Urban Rail Transit Operation in theWorld in 2020: A Review

HAN Baoming, YANG Zhixuan, YU Yiran, QIAN Lei, CHEN Jiahao, RAN Jiangliang, SUN Yajie, XI Zhe

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The article summarizes the statistics for 2020 on operation of urban rail transit systems in the world, which are classified into metro, light rail and tram systems in line with the widely accepted international standards. The statistics show that 535 cities in 77 countries or regions worldwide have hosted urban transit systems by the end of 2020, with the total length reaching 33, 346 kilometers, among which, the metro system accounts for 53%, the light rail 5% and the tram 42%. The ridership of metro and light rail worldwide totals 70.794 billion trips in 2019, with an average of 8, 300 trips per day. Urban rail transit systems have been built and put into operation in 45 Chinese cities and the total length in operation has reached 7978.19 kilometers by the end of 2020. It is found that China ranks the first in the world in terms of the size and ridership of its urban rail transit system networks.
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Overview of urban rail transit lines in mainland China in 2020

Hou Xiufang, Mei Jianping, Zuo Chao

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.By the end of 2020, 45 cities in mainland China opened 7978.19km for urban rail transit operation, and the length of new operation lines in 2020 was 1241.99km. In 13th Five-Year, five years, Chinese mainland"s new city rail transit operation lines totaled 4360 km, with an average annual opening of 872 km. In 2020, a new round of construction planning (or adjustment of planning scheme) of eight cities will be approved and publicized. The approved projects involve 587.95 km of newly added urban rail transit lines, with a total investment of 470.986 billion yuan. During the 13th five year plan, the national development and Reform Commission has approved the new round of urban rail transit construction planning or adjustment of construction planning, involving a total of 4001.74 km, with a total planned investment of 29781.91 billion yuan.
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Design of Study on Channels technology of Shield-bored Tunnels of of Nanjing Metro

Peng Hongxia

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In order to solve the structural damage of Metro Shield-bored Tunnels caused by mechanical and electrical equipment installation drilling construction, in recent years, Shield -bored tunnel segment embedded channel technology has been greatly developed. At present, the research on the 13th five year plan line of Nanjing Metro is taken as the background, In order to solve the high cost、durability and later replacement of embedded channel, Two kinds of installation schemes are put forward, which are special fixed parts + Non-embedded channel system and embedded sleeve + external channel system, it is also a further exploration and extension of tunnel tunnel technology. In this paper, through model selection, calculation and simulation analysis, the key technical problems such as special fixed parts + Non-embedded channel system and embedded sleeve + external channel system are studied, It is considered that the two schemes are feasible and safe, It can be selected according to the actual situation of the line, In order to achieve the purpose of convenient construction and easy replacement.
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Study on the Embedded Channel of the OCS in the Metro High Headroom Shield Tunnel

wangyifei

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At present, a large number of embedded channel technology has been adopted in subway projects, In traditional low headroom shield tunnels, each ring segment is pre-embedded with a full ring single channel, however, the embedded channel plan should be determined according to the OCS installation and the force calculation in the high headroom shield tunnel, Through the comparison and analysis of three types of OCS channel installation schemes in high headroom shield tunnels, Using ANSYS software to carry out finite element force calculation and analysis on the pre-embedded single channel and double channel, Studies have shown that there are potential safety hazards when using single-channel in high-clearance shield tunnels, In order to ensure the safety and reliability of the OCS, It is recommended to use the double channel suspension in the high headroom shield tunnel. Through application and practice in the Hangzhou-Shaoxing subway project, Provide a certain reference for the subsequent subway engineering design plan.
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Analysis and Application Research of Metro Fire Hydrant System Scheme under New Fire Regulations

MU YuHong

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This paper studies and analyzes the project characteristics of the subway fire water supply system under the new regulations under the different phases of the fire protection code, the difference between the new and the old code, compares and studies the urban rail transit lines in different periods, and summarizes the subway stations in each phase. The characteristics of the plan of the fire protection system, according to the difference of the plan with or without fire stabilization equipment, analyze how to realize the automatic start of the pump, and analyze the difference of the start pressure value of the pump with two water source conditions of the fire tank for water suction and municipal direct pumping. Propose an optimized plan for the fire protection system of subway stations, continuously adjust the design ideas, and combine on-site commissioning and operation experience to find a fire protection plan that meets the characteristics of the subway, and improve the fire safety of subway operations.
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Research on the optimize configuration of cutters for long distance shield tunneling in gravel stratum

ZHANG Jinxun, YIN Mingun, Jiang Hua, Zhou Liugang

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Aimed at the characteristics of long distance shield tunneling in gravel stratum, the concept of multi-dimensional gradient layout of advanced cutters is proposed. The multi-dimensional layout ensures the stability of cutter head in long-distance excavation, and the gradient layout makes the alloy blocks of advanced cutters with different heights overlap to realize the wear "relay". In this study, we selected the most suitable design for the project after comparing several cutter heads and cutters layout. Meanwhile, the wear resistance and impact resistance of the alloy blocks were optimized in order to avoid the impact fatigue failure in long-distance excavation. Based on the engineering of the section from Cigezhuang Station to No. 1 Air Shaft in Beijing new airport Metro line, the final cutter head design scheme is obtained through scheme comparison and selection. Furthermore, the cutting tool wear results and tunneling parameters in the tunneling process are analyzed. The data show that the long-distance tunneling in gravel stratum with multi-layer advanced cutters can be divided into two stages: ploughing with high cutter mainly and ploughing with both high and low cutters. In the first stage, the wear coefficient of the 155mm advanced cutters are reduced due to the cutters with 190mm height. In the second stage, the normal tunneling can be maintained within a certain distance, which means that the tunneling distance can be extended. It can provide reference for similar engineering construction in the future.
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Design and Application of Train-Ground Wireless Transmission System for Urban Rail Depot

JIAO Deyu, SHI Yong, ZHANG Zengyi

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It introduces the Train Control and Monitoring System of the urban rail vehicle and the existing buildings and layout of a certain urban rail depot, and then analyzes the data transmission requirements of Train-Ground Wireless Transmission System. And then it designs the system scheme, including the selection of wireless module installation location, system topology, equipment selection and detailed parameters. Also, it describes the installation, wiring and debugging of field equipment, and tests the signal intensity and data communication, which verifies and confirms the effectiveness of the designed system. The application results show that the designed Train-Ground Wireless Transmission System meets the data transmission requirements, and the implementation of the project has an important guiding significance for the existing urban rail depot.
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Resilience Assessment of an Urban Rail Transit Network under Emergencies

LIU Fuhua, YIN Yong, CHEN Jinqu

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Assessing the resilience of urban rail transit (URT) network under emergencies has practical significance to enhance the URT system’s operation. An URT network performance indicator which takes URT network’s topology structure and passengers’ travel into consideration is proposed here, and the URT network’s resilience is measured by taking URT network’s performance recovery rate as indicator. Finally, the resilience of Chengdu subway network under emergencies is analyzed by proposed models. The result indicates that the performance loss of URT network is in proportion to emergencies’ duration. Compared with non-transfer stations, the failure of transfer stations will lead to higher URT network performance loss. URT network’s resilience is inverse proportion to the duration of emergencies. For URT operator, the URT network’s resilience under emergencies can be improved by strengthening equipment maintenance and optimizing rescue sequence.
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Innovative design of fire water supply system for rail transit engineering under new construction mode

Jiangqin

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With the rapid development of urban rail transit, various new construction modes such as TOD development for depots, integrated transportation hubs, and deep-buried stations have emerged in domestic urban rail transit. In the absence of corresponding design specifications, through the analysis of actual engineering cases Research, under the premise of ensuring fire safety, it is necessary to rebuild a fire water supply system with rail transit characteristics under the new construction mode. It is proposed to use a combination of normal and temporary high-pressure fire water supply in deep-buried stations; the fire water supply system of underground stations uses municipal tap water for stabilization, and adopts a new design concept of high-level water tanks and fire pools; integrated transportation hub subway fire hydrants and sprinkler systems Setting plan; fire protection design plan for the throat area of the development depot with cover, individual fire protection design parameters of different forms of depot, design plan for single under cover, etc., to provide new design ideas for rail transit water supply and drainage design, and to standardize Provide basis for revision.
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Discussion on the planning and layout of railway hub and urban rail

Zhang Mingzi, Feng Xipei

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Based on the research of the layout relationship between urban rail station within the hub and the railway station as a starting point. Combing and analyzing the representative excellent hub cases in China. Focus on the development process of hub, changes in the importance of urban rail transit to hubs,the positioning of city and urban rail, the change of planning layout, the relationship between the railway outbound layer and urban rail station hall, etc.. Summarize the layout, characteristics, principles and key factors of the urban rail station in the hub, and discuss the development trend of urban rail transit layout in the current development situation of high-speed rail hub.
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Research on Sustainable development of MTR

ZHANG Jin, YUAN Jia Yue

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With the continuous growth of urban rail transit operation scale of China, the importance of sustainable development of rail transit is increasingly prominent. As the only profitable Metro Company in the world, MTR"s business model is of great significance of China"s mainland rail companies. Through the analysis of the profits of various businesses, it is found that as MTR enters the operation Era, "Rail + property" is no longer the key factor of its sustainable development. Instead, it is the operation business such as Transport Operations and Station Commercial Business. The profit of these businesses is derived from the large amount of passenger flow within the MTR, which is known as "flow realization ". This shows that land resources can only support the construction of rail transit, and it is passenger flow that can support its development.
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Development and thought of Urban Rail Transit Connection

Wei Jiarong, An Shuanzhuang, Zhang Zhening, Dong Binjie

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In order to analyze the existing problems of urban rail transit connection in the legal system and system mechanism , the development status in technology and practice were summarized. It proved that there are four problems in the legal system and mechanism of rail transit connection.The cause of the problems is the lack of standardized and standardized management system, which needs to be improved in terms of legal system and system mechanism. The authors put forward ten management suggestions and implementation of security recommendations, which are helpful to solve the problems. The management suggestions involves planning, construction and operation. It is hoped that the suggestions can provide reference for other cities.
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Study on Vibration and Secondary Structure Noise Control of Zhujiang Road Station of Nanjing Metro Line 1

She Cai-gao, Zhang Bo-lin, Liu Tie-xu, Chen Peng, Huo Hai-long

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With the rapid development of urban rail transit and the quality improvement of people"s life, environmental vibration and noise problem caused by urban rail transit has attracted more and more attention. It is one of the main problems faced by the subway after its operation. In order to solve the indoor noise problem the subway building next to Zhujianglu Station of Nanjing Metro Line 1, remediation measures were taken in subway line by rail grinding and the replacement of vibration reduction nested fastener. In order to evaluate the remediation effect, comparative tests were conducted on the tunnel wall vibration, indoor vibration and noise before and after the implementation of the measures. The test results show that the vibration and noise level of Zhujianglu Station and surrounding buildings is greatly reduced after the remediation, and the remediation effect is obvious.
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Study on the Design and Construction Technology for small Clearance Overlapping Tunnels Built by Mining Method

Jia Xiao, Feng Xin, Zheng Jie, Xia Ruimeng, Zhao Lingjie

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The article reviewed the research results of the adjacent tunnel affected area and corresponding countermeasures, investigated the relevant design and construction experience of domestic overlapping tunnel. Aiming at the overlapped four-hole tunnel that Beijing Metro Line 19 Financial Street Station to Pinganli Station and Line 3 Fuchengmen Station to Pinganli Station, the influence on the deformation of the existing upper tunnel caused by the excavation of lower tunnel was studied. several design and construction technical measures for the actual situation was proposed. The construction process was analyzed with MIDAS-GTS, and the influence of construction stage on the existing structure, surface settlement and the change process was discussed. The research indicates that it is feasible to design and construct overlapped four-hole tunnels in Beijing by taking measures such as advanced grouting, strengthen the stiffness of initial support and permanent support, strengthen the interlayer soil, which can meet the tunnel design requirement. It can provide some guidelines for the design and construction of similar projects.
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Opinion on Adjustment Direction of Urban Rail Transit Planning and Construction Management Policies in China

LI Ming

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China has adjusted the urban rail transit planning and construction management policies for many times, which has played a good role in regulating the pace of urban rail transit construction in different periods. This paper first reviews the development of urban rail transit in China, and compares the changes of major policies in planning and construction management. Finally, combined with the problems arising from the practical application of policies, the paper judges the possible direction of policy adjustment in the future for the exchange and discussion of people in the same industry.
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Research on The Related Business of Urban Rail Transit in Japan and Its Implication to China

ZHANG Xuetong, LI Mingyang, LIU Liqin

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With the rapid development of domestic rail transit, the demand for construction financial support will be huge. The operating railway lines is increasing as well, the demand for operation and maintenance funds will continue to increase. How to realize the sustainable development of rail transit will be a immediate problem. After 150 years of development, Japanese railway companies basically can achieve profitability. Taking Tokyo metropolitan area as an example, this paper analyzes the operation status and development path of three-level rail transit enterprises, finds that developing related business is the key to the sustainable development of Japanese rail transit. Through the analysis of business form and profit status of related business of Japanese railway companies,this paper finds that chinese rail transit can develop related business through the three stages of ‘real estate, retail and service, diversified business’, and combine the Japanese business model to practice the business mode of sustainable development.
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Experimental study on the environmental vibration source of Wenzhou Suburban Railway elevated line

罗伟

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Wenzhou suburban railway line S1 is the first pilot demonstration project of suburban railway in China, in order to provide technical reference for environmental assessment of suburban railway, an experimental study on the source intensity of environmental vibration was carried out in S1 line. The results and suggestions are as follows, the test data of the bridge deck measuring points have better stability and reliability compared with the ground measuring points, so the bridge deck measuring point is recommended for the analogy test of vibration source intensity of suburban railway elevated line. The measurements of vibration source intensity VLzmax using ISO 2631-1:1985 weighting standard is about 2~4dB smaller than that using ISO 2631-1:1997 weighting standard. 94.1dB(using ISO 2631-1:1997 weighting standard) or 90.6dB(using ISO 2631-1:1985 weighting standard) is recommended for vibration source intensity of suburban railway, its corresponding line condition is straight line, and the train passing speed is 95km/h. For every 15km/h increase of train passing speed, the recommended correction value is +3~5dB. For every 700m reduction of curve radius in curve section, the recommended correction value is +4.5dB.
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Analysis on the Influencing Factors of Pedestrian Spatial Continuity Around Beijing Rail Transit Stations

GAO Jie, WANG Xiaoyan, ZHANG Yunan

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Taking 70 rail transit stations from the Third Ring Road to the Fourth Ring Road in Beijing as samples, this paper analyzed the continuity of the walking space around the stations from two aspects: the integrity of the walking network at the macro level and the smoothness of the walking path at the micro level. The dominant problems and influencing factors were explored by means of satellite map observation, map marking and field survey. The results show that: the overall degree of pedestrian network around stations in Beijing urban area is mainly affected by main roads, expressways and viaducts, followed by rivers and railways, but their cutting effect is far greater than that of urban roads. A small number of stations are affected by elevated rail transit lines, resulting in the failure of effective integration of ground and ground space around the entrance and exit. From the perspective of time and space barrier, the environmental factors affecting the smoothness of pedestrian path are mainly reflected in three aspects: the connectivity of crossing facilities, the time blocking effect of grade intersections and the dual guidance of buildings (structures). In order to realize the pedestrian accessibility of subway passengers from the exit to the destination, this paper put forward some suggestions on the construction of smooth and continuous walking space from the aspects of track line and site selection, station entrance and exit space design, space environment elements and policy guidance.
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Discussion on Construction Planning of Catenary's Key Equipment Health Management Platform

WANGRuifeng, LAIShenggang, JIANGZhongzhi

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In order to ensure the safe and stable operation of the Metro, conduct the construction and program research of the PHM (Prognostics and Health Management) platform for the key equipment of the metro catenary. This platform takes big data and cloud computing technology as the core, designs the PHM platform system structure for key catenary equipment, integrates the maintenance and management information of the catenary and testing and monitoring data, evaluates the hardware resources required by the system, and proposes a combination of the existing catenary monitoring and management system Hardware solutions. Realize the three major functions of fault diagnosis of key equipment and parts of the catenary based on Bayesian network inference model, multi-dimensional health evaluation and estimation of remaining time before maintenance based on hidden Markov model, and finally form a set of systems from zero to zero Closed-loop health management system for the contact network of components. This paper discusses the necessity and feasibility of researching PHM platform for key catenary equipment, and discusses the system structure, functional design and visual presentation of the PHM platform for key catenary equipment.
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The Design of Double-line Continuous U-beam Bridge With Variable Width

LiuBingfei, CHEN Yipeng

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In this paper, a detailed design of double-line continuous U-beam bridge with variable width of urban rail transit is carried out. This bridge make a three-span continuous structure, it have a main span of 45m. With the width of 11.01m at the small mileage and 14.96m at the large mileage, it have a variable width far greater than that of other bridges of the same type, so the difficulty of the design process increases rapidly. The design combines the continuous structure system with the standard U-beam, it greatly reduces the structural volume, and forms a lightweight landscape together with the station. The design of the mid-web variable width segment adopts the system design method of “web thickens +box added + web forked”, which the structure changes from three webs to four webs during the process of broaden its width. The whole bridge is so complex and needs further study. By establishing the beam element model and three dimensional finite element model of the whole bridge, the transverse stress analysis, the local stresses of the variable width segment, the support reactions and multiple web shears distribution and the overall spatial stress effect analysis are carried out. The stress mechanism of the bridge is further discussed. Through the optimization analysis of the whole bridge, the thickness of the web and bottom plate of the bridge is reduced to further improve the mechanical performance of the structure, which provides a rational design method for this type of bridge.
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A Research on the Cultural Construction of Public Space in Urban Rail Transit Based on Visual Communication

ZHAI Leilei, XIA Haishan

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Taking the relationship between urban rail transit public space culture and visual communication as the point of penetration, this paper elaborates that urban rail transit public space culture means inheritance and development to urban culture, visual communication is an important way of urban rail transit public space culture communication, and urban rail transit public space culture is the inner core of visual communication. The core problems and construction principles of visual communication are analyzed, and two construction strategies of visual communication are revealed with specific cases: the first is the integration of visual communication paths; the second is the diversification of visual communication paradigms. Finally, the visual communication form with digital virtual reality technology as the development trend is proposed, which is of great significance for the future construction of urban rail transit public space with regional urban cultural characteristics.
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Vibration prediction of precision instruments on the site of Changchun Metro Line 7

nijingfeng

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Changchun rail transit line 7 is to be built under a precision instrument factory (minimum horizontal distance is 50m, covering soil in the interval is 16.5m). It is possible that the vibration of operating vehicles may affect precision instruments such as presses in the factory. According to this, this paper analyzes the vibration propagation law of similar sections of Changchun Rail Transit Line 1 and line 2, and analyzes the impact on precision instruments in the plant area along Changchun rail transit line 7. The results show that: (1) in a certain horizontal distance range, the acceleration effect of driving vibration can be magnified; (2) in a certain buried depth range, the speed and displacement effect of driving vibration can be magnified; (3) according to the vibration propagation law of similar sections of Changchun rail transit line 1 and line 2, it is predicted that the ordinary track vibration of line 7 can meet the requirements if the floating slab track is used To improve the damping effect.
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Explorations and Practices of Regional Rapid Rail Lines Planning in Shanghai

Jin Yu

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In order to acquire a better understanding of regional rapid lines, this paper studied the implementation evaluation of regional rapid lines planning. Based on the Shanghai comprehensive transportation annual report and the smart card data, the evaluation focused on the realization of planning objectives and passenger flow characteristics. The result shows that, with regard to regional rapid rail lines, the average traveling distance carried is relatively longer, and the passenger flow density is relatively higher, while the load density is relatively lower comparing to the metro lines. From the spatial distribution aspect, the passenger flow distributes along the line, agglomerates in the central city area and partly clusters within the new town. From the temporal distribution view, the passenger flow clusters cumulatively within the peak hours and the agglomeration effect is prominent. Finally, suggestions of regional rapid lines planning and passenger flow forecasting are put forward.
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Research on Urban Rail Transit Public Security Management based on Situational Crime Prevention

YUAN Guijuan, XUE Huaizu

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Opinions on ensuring the safe operation of urban rail transit (No.13) points out that urban rail transit is the backbone of urban public transport system and an important part of urban comprehensive transportation system. The safe of urban rail transit is of great significance to the protection of people's lives and property and the maintenance of social security and stability. This study combs the main threats of urban rail transit public safety in China, explains the basic connotation and strategies of situational crime prevention, and analyzes the feasibility on guiding urban rail transit public safety governance. On the basis of feasibility, the study puts forward the specific path of situational crime prevention: increase the difficulty of public safety incidents; strengthen the prediction and monitoring of public security incidents; reduce the illegal and criminal income of the perpetrators of public safety incidents; create a safe and orderly riding environment, which provides reference for strengthening the governance of public safety of urban rail transit.
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Research on Evaluation Index System of Urban Rail Transit and Bus Feeder Service

TAN Yingjia, ZHU Yizhou, LI Shaolong

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It is an indispensable part of the priority development strategy of urban public transport to improve the transfer between urban rail transit and bus. In order to effectively evaluate the service level of bus and rail transit, timely discover the shortcomings existing in the transit system, nine representative evaluation indexes are selected from the four integration aspects of facilities, network, operation and ticket price. Then, a multi-level structure evaluation index system of feeder service is constructed and the calculation method of index weight of each level is also given. Finally, this paper analyzes the rail transit and bus connection system in Shenzhen. The research has improved the index system construction and evaluation method in the public transport feeder service, which is helpful for the public transport authority to formulate relevant service improvement strategies and measures.
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Volume 39,2026 Issue 2

Volume 39,2026 Issue 2

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