大型建筑基坑施工对临近地铁车站的影响分析

Influence Analysis of Large Building Foundation Pit Construction on Adjacent Metro Station

以南昌市临近某建筑基坑工程的地铁车站为研究背景,建立了有限元计算模型,对基坑开挖过程中引起地铁车站及周围地层的变形进行分析。研究结果表明:基坑开挖过程中,周边地层出现向基坑内部移动的水平位移;竖向位移主要出现在基坑底部,表现为坑底隆起,且位移值随着基坑开挖而逐渐增大。受开挖卸载作用,车站结构在水平方向出现向基坑方向移动的水平位移,竖直方向出现上浮变形,其中最大水平位移为0.43 mm,最大上浮位移为1.25 mm。对基坑四周施加围护结构有效地抑制了基坑内部土体卸载引起基坑外部的土体应力的变化,且从四周向中间开挖较由中间往四周开挖临近地铁车站最大水平位移减小了38.80%,最大竖向位移减小了20.23%。

Taking a metro station next to the building foundation pit construction in Nanchang City as the research background,a finite element model is established to analyze the deformation of the stratum around metro station during the foundation pit excavation.The research results show that during the excavation of the foundation pit,the horizontal displacement in the surrounding stratum is moving to the internal area of the foundation pit,while the vertical displacement mainly occurs at the bottom of the foundation pit,appearing as a bulge at the pit bottom,and the displacement value gradually increases with the excavation of the foundation pit.Under the effect of excavation and unloading,the station structure in the horizontal direction moves horizontally toward the foundation pit,and the floating deformation occurs in vertical direction.The maximum horizontal displacement value is 0.43 mm,and the maximum floating displacement value is 1.25 mm.Enclosing the pit surrounding with envelope structure effectively inhibits the soil stress change outside the pit caused by the pit internal soil unloading,and the maximum horizontal displacement of excavation from the periphery to the center is reduced by 38.80%compared to that of the excavation from the center to the periphery,the maximum vertical displacement value is reduced by 20.23%.