西安地铁深基坑施工过程中的变形规律研究

针对西安地铁#4线某站深基坑施工,采用摩尔-库伦弹塑性理论,运用FLAC3D软件建立有限元分析模型,对不同工况下的围护结构水平位移及地表沉降进行模拟,将不同工况下的围护结构的水平位移和地表沉降的模拟值与其实测值比较分析,得出基坑开挖对周围地表沉降的影响距离为1.5倍的开挖深度;距离围护桩顶2/3桩长的位置是最容易出现危险的地方,且模拟值大多小于实测值,究其原因是没有考虑黄土的湿陷性、雨季施工及车辆动荷载等因素。

Study on Deformation Law in Construction of Deep Foundation Pit for Xi'an Metro Engineering

In relation to the construction of deep foundation pit in a station of Xi＇an Metro Line 4, a FEA model was established by using Mohr-Coulomb Elastic-Plastic Theory and FLAC3D software to simulate the surrounding structure＇s horizontal displacement and the ground subsidence under different cases. By comparison between the simulated and measured values, it was found that the distance, wherein the subsidence of surrounding ground surface was affected by the excavation of deep foundation pit, was 1.5 times the excavation depth; the point that is the two-third of pile length away from the retaining pile top was the position where hazard arises most easily with the simulated value less than the measured value mostly, which was resulted from no consideration of loess collapsibility, rainy season construction and dynamic load of vehicle etc.