[关键词]
[摘要]
随着装配式车站建设的大范围推广应用,装配式车站面临着也越来越多复杂地质情况。装配式车站在软硬不均地层中,结构的纵向受力特性带来的影响更为突出。本文以深圳地铁某装配式车站为工程背景,采用有限元数值模拟方法构建壳-弹簧模型,研究在均匀及软硬不均地层的复杂工况下,装配式车站结构纵向沉降与受力特点。研究结果表明:位于均匀地层中的结构纵向受力主要受中立柱的影响,但其影响较小;位于软硬不均地层中的装配式车站结构纵向不均匀沉降较为明显,尤其在结构底板更为突出,顶板和侧墙结构其差异沉降的速率相对较缓;此外,结构环与环之间的抗剪刚度对车站纵向的不均匀沉降影响较大;软硬不均地层中不仅对车站结构纵向受力存在影响,也对车站结构的横向受力存在一定的影响,顶板拱顶、拱肩弯矩增加约10%,拱顶轴力减少约8%,在设计设计中应考虑此因素的影响;在岩面突变地层中底板结构的剪力在突变位置存在突变,对结构的环缝受力不利,在渐变地层中剪力变化相对均匀;同时在软硬不均地层中存在结构的纵向变形,加大环缝的张开量,在环缝宽度的控制中应考虑此因素的影响;综上所述,对于软硬不均差异较大的地层,应采取一定的加固措施提高软土地层的承载力,减少结构的纵向不均匀沉降。
[Key word]
[Abstract]
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.
[中图分类号]
U231
[基金项目]
住建部研究开发项目(2020-K-14),国家重点研发计划(2017YFB1201104)