膨胀土深基坑开挖对邻近地铁设施变形的影响

摘要

Due to the rapid development of metro and light rail transit in Chinese cities,in the expansive soil distribution area,a lot of expansive soil foundations are located along metro lines which have great impact on the safety of subway tunnels and stations. As a kind of special soil that causes seri-ous damages to engineering,the deep excavation of expansive soil foundation adjacent to subway facilities is a particularly important issue to be studied. Based on the case of Honghe Station on Chengdu metro Line 2,the deformation influence of expansive soil deep foundation adjacent to subway facilities is numerical simulated by using FLAC3D software and expansive soil shear strength reduction method. The results of numerical calculation are similar to that of the field tests: the maximal displacement of metro tunnel and Honghe Station can satisfy the engineering control demands. That is to say,the expansive soil shear strength reduction method could be used for the cal-culation and analysis of expansive soil foundation. This re-search can provide a reference for similar engineering design and construction.%随着全国各大城市地铁以及城市轻轨交通项目的快速兴建,在膨胀土分布区域,一系列的膨胀土深基坑工程位于地铁线路周边,对地铁隧道及车站的安全产生影响.膨胀土作为对工程危害严重的特殊土,膨胀土深基坑的开挖对邻近地铁设施的影响分析显得尤为重要.为此,以邻近成都地铁2号线洪河站某膨胀土深基坑工程为背景,运用FLAC3D数值软件建立计算模型,采用膨胀土抗剪强度折减的方法,对膨胀土深基坑分层开挖对邻近地铁设施的变形影响进行分析计算.计算结果表明:地铁隧道及车站的最大位移符合控制要求,数值计算结果与现场测试结果相近,表明考虑膨胀土抗剪强度衰减的方法可以用于膨胀土基坑分析计算,成果可为类似工程的设计和施工提供参考.