上海轨道交通异形超深基坑施工过程数值模拟分析

Analog Analysis of the Numerical Value of Difform Deep-pit Engineering in Shanghai Metro

利用FLAC3D有限差分法分析软件,针对上海轨道交通某开挖深度为27 m的异形超深基坑建模计算;计算中考虑土、围护结构、水平支撑体系共同作用,三维计算模拟分层开挖施工工况,并与平面二维计算进行比较;得出了该异形超深基坑的变形计算结果和变形控制要点。此类基坑使用二维计算软件来模拟的计算误差较大,而三维计算能充分考虑基坑的空间效应。该异形超深基坑不同于一般深基坑的变形特性,应充分考虑基坑异型带来的薄弱点,在结构平面的变化点应重点加强。

In this paper,a software of finite differential method FLAC3D is used to simulate a difform ultra-deep foundation pit of Shanghai metro,the excavation depth is 27 m.Considering the interactions between the soil,structure and level support,a three-dimensional finite element model will simulate the layered excavation and is compared with the two-dimensional plane calculation.At last,the general deformation laws of difform ultra-deep excavation are obtained,which show that the control points of deformation and the deformation characteristics of difform ultra-deep foundation pit are different from those of the conventional pit.