上海地区地铁超深基坑及深基坑变形有限元分析

Deformation Analysis of Subway Ultra-deep and Deep Excavation in Shanghai by FEM

利用PLAXIS有限元程序,对上海地铁某开挖深度为24.3m的超深基坑进行了模拟计算,分别分析了土体加固、围护墙体插入深度、钢支撑预应力、墙体与支撑刚度等对变形的影响。将计算结果的变形规律进行分析,得到了超深基坑的一般变形规律和变形控制要点以及超深基坑不同于一般深基坑的变形特性。结论可用于超深基坑的设计优化和变形预测。

In this paper, PLAXIS （FEM） is used to simulate a ultra- deep foundation pit of Shanghai subway in which the excavation depth is 24.3m, and the influence of soil stabilization, the inserted depth of enclosure wall, the prestress of steel brace, and the stiffness of wall and brace on the deformation is analyzed respectively. Through analyzing the calculation results we got the general deformation laws of ultra - deep excavation, the control points of deformation and the deformation characteristics of ultra - deep foundation pit which are different from that of the general deep one. The conclusions can be used for the design optimization and the deformation prediction of ultra-deep foundation pit.