基于FLAC^(3D)的深基坑围护结构变形规律分析

Deformation Rule Analysis of Foundation Pit Enclosure Structure Based on FLAC^(3D)

关于如何预测地连墙的最大水平位移和验证结构设计的合理性,成为地铁车站深基坑开挖时的重要问题。以无锡地铁二号线五爱广场站深基坑的工程场地条件为实例,建立FLAC 3D计算模型,针对该深基坑的开挖过程进行了数值模拟,对比围护结构的侧向位移实测值和模拟值,相对误差仅为5%,说明通过数值模拟来预测地连墙的最大水平位移和验证结构设计具有合理性,是可行的。并分析了围护结构水平位移的变化规律,说明内支撑预应力对抑制地连墙水平位移的作用非常明显。深基坑内被动区土体的超载导致了其中部分土体的力学性质发生变化,对地连墙的水平位移量有显著的抑制作用。

Currently,the most important problem in deep foundation pit excavation of subway station is how to predict maximum horizontal displacement of ground-to-wall and to verify rationality of structure design.Take engineering site condition of deep foundation pit in Wuai square station,No.2 subway line,Wuxi as example to build FLAC^（3D） calculation model;carry out numerical simulation calculation for the excavation process of this deep foundation pit;compare lateral displacement measured value and simulated value of building envelope,the relative error is only 5%,accounting for that it is reasonable to predict maximum displacement of ground-to-wall and verify rationality of structure design by numerical simulation.Analyze changing rule of building envelope horizontal displacement,showing that inner support prestress has big effect on horizontal displacement of ground-to-wall.Overload of foundation pit passive area soil mass had caused mechanical properties changing of some soil mass with remarkable inhibiting effect on horizontal displacement of ground-to-wall.