为进一步明确城市轨道交通环线的规划理念和设计思路，本文以西安轨道交通8号线为例，结合西安市城市空间结构发展、线网规划编制历程，总结了环线的规划构思、建设必要性、廊道选择、线路规模、建设时机、客流特点、运营组织等方面的特征。8号线作为西安轨道交通线网中唯一的环线，布置在主城区内二环至三环之间，符合西安市城市空间发展的用地布局结构，并串联了城市中心的多个核心组团，具有换乘客流量大、平均运距小、同区间上下行方向断面客流量不均衡性较小、高峰小时客流断面呈现较均衡、等客流特征，初、近、远期全线开行一个大交路。工程设计、建设过程中存在场段选址困难、出入线较长、转弯路段线型差、实施难度大、既有换乘站未预留换乘条件需改造等难点。基于8号线的规划设计研究，本文同时对环线的规划理念、客流研判、互联互通等方面提出了相关建议。

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.

U293.5

陕西省住房和城乡建设厅2019年陕西省工程建设标准编制