隔水帷幕深度对苏州地铁隧道结构影响分析

Analysis on Influence of Water-insulating Curtain Depth on Existing Metro Tunnels: Case Study on a Foundation Pit in Suzhou

随着城市地铁周边建设工程项目越来越多,研究邻近地铁的基坑施工对地铁隧道影响具有重要意义。基于苏州地铁1号线某基坑工程,采用FLAC 3D程序,分析研究在既有地铁隧道周边,基坑采用不同的隔水帷幕深度情况下,地下水渗流作用对地铁隧道的影响。数值模拟中考虑在2种不同的隔水帷幕深度时,基坑降水后隧道的位移场以及隧道管片应力。研究结果表明:1)增长隔水帷幕深度有利于控制隧道周围孔隙水压力降低,有利于减小隧道结构变形。2)随着隔水帷幕深度增加,减小了基坑降水引起隧道结构应力的降低。

As more and more construction activities take place adjacent to existing Metro lines,the study on the influence of the foundation pit construction on existing Metro tunnels becomes more and more important.In this paper, the influence of the groundwater seepage on the existing Metro tunnel under different water-insulating curtain depths is studied by means of FLAC 3D software,with a foundation pit adjacent to No.1 Line of Suzhou Metro as an example.In the simulation,the displacement field of the Metro tunnel and the stress of the tunnel segments are studied under 2 different depths of the water-insulating curtains.The study results show that：1）The increase of the depth of the water-insulating curtain is helpful for the reduction of the pore water pressure around the tunnel,and in turn helpful for the control of the structural deformation of the tunnel;2）As the depth of the water-insulating curtain increases,the stress on the tunnel structure induced by the dewatering in the foundation pit reduces.