繁华路段地铁站深基坑变形规律研究

Deformation Law of Deep Foundation Pit of Subway Station in Busy Traffic Section

摘要: 针对基坑开挖会引起周边建筑环境发生改变的风险，运用FLAC(3D)软件对繁华路段地铁站的深基坑工程开挖全过程进行仿真模拟分析，探讨了基坑开挖过程中地下连续墙的位移变化规律，地表沉降变化规律，支撑轴力变化规律，高层建筑对深基坑开挖影响规律。研究发现，围护结构变形曲线整体上向“弓形”发展，位移逐渐趋于稳定；基坑周围地表沉降位移随开挖深度增加，地表沉降最大值位置保持稳定；伴随开挖深度增大，支撑轴力不断增大，支撑轴力变化幅度依次降低；附近既有高层建筑物条件下，围护结构水平位移大于其他位置变形，支撑轴力有明显的上浮，此条件下的深基坑开挖对周围环境的影响较大，施工中应严控超挖，及时支撑。

Abstract: In view of the risk that the foundation pit excavation will cause changes in the surrounding condi-tions, the numerical simulation analysis of the foundation pit excavation of the Shangchuan Metro Station in Line 12 of Shenzhen is carried out by FLAC(3D) software. The deformation law of dia-phragm wall, the variation law of supporting axial force, the deformation law of ground surface, as well as the distribution law of stress in the foundation pit are analyzed during the foundation pit excavation process. It is found that the deformation curve of the retaining structure develops to-ward the “bow shape” as a whole, and the displacement gradually becomes stable. The surface set-tlement displacement around the foundation pit increases with the increase of the excavation depth, and the maximum value of the surface subsidence remains stable and large, the supporting axial force is continuously increased, and the variation of the supporting axial force is sequentially decreased. Under the condition of high-rise buildings nearby, the horizontal displacement of the retaining structure is larger than that of other locations, and the supporting axial force has obvious upward floating. The deep foundation pit excavation under this condition has a great influence on the surrounding environment. Excavation should be strictly controlled during construction and supported in time.