基坑开挖对邻近地铁车站安全影响的三维有限元分析——以西朗公交枢纽站为例

随着城市地铁工程的快速发展,地铁周边建筑物基坑的施工必然会对邻近的地铁车站产生一定的影响,特别是超近距离的基坑施工;因此必须进行更为可靠的安全评估。借助有限元分析软件MIDAS/GTS,考虑边界条件、土层参数等工况条件,建立了基坑开挖的三维有限元模型。先计算出基坑开挖前地铁结构的初始应力状态,再计算出由于基坑施工引起的位移、内力等的变化,根据该变化值来判断基坑施工对地铁结构的影响。同时,为满足超近距离安全评估可靠性较高的要求,提出运用Plaxis有限元模型进行复核,为超近距离地铁车站的深基坑施工安全评估提供了操作可行的方法。

Case Study on 3D Finite Element Analysis on Influence of Cutting of Foundation Pit on Safety of Existing Adjacent Metro Station

With the rapid development of urban Metro projects, the construction of foundation pits will have impact on existing adjacent Metro stations. As a result, a more reliable safety assessment system is needed when the foundation pit is close to the existing Metro station. The 3D finite element model is established for foundation pit cutting by using the finite element analysis software MIDAS/GTS, considering the boundary conditions and parameters of soil strata. First, the initial status of the Metro station is calculated; then the displacement and internal force variation of the Metro station induced by foundation pit cutting is calculated. The calculation results can be used to determine the influence of foundation pit cutting on the Metro station. Meanwhile, it is proposed that finite element model should be used for checking, which provides a feasible method for safety assessment of Metro station.