深厚圆砾土层深基坑截水帷幕深度对紧邻地铁隧道变形研究

Research on the Effect of Waterproof Curtain Depth of Deep Foundation Pit in Round Gravel Soil on Deformation of Adjacent Subway Tunnel

基于稳定渗流问题变分原理对深厚圆砾土层深基坑截水帷幕深度对紧邻地铁隧道变形影响进行理论研究。基坑截水帷幕长度很大程度上决定着基坑周边地下水渗流场形态,导致坑外孔隙水压力变化,进而改变土种应力并作用于隧道周围引起隧道受力和变形的不同。采用MIDAS/GTS大型三维有限元软件,分别考虑了截水帷幕深度为15 m,20 m,25 m时,隧道的变形特性并进行对比分析。结果表明,增加基坑截水帷幕深度可以有效地保护基坑周边地铁区间结构。

Based on the variation principle of steady seepage problem,the influence of waterproof curtain depth of deep foundation pit on the deformation of subway tunnel was studied.The length of the waterproof curtain of the foundation pit mainly determined the shape of the seepage field of the groundwater around the foundation pit,which led to the change of pore water pressure outside the pit,and then changed the soil stress applied to the surrounding tunnel.In this article,MIDAS/GTS large-scale3D finite element software was adopted to consider the deformation characteristics of the tunnel when the waterproof curtain depth was15m,20m and25m,respectively,and a comparative analysis was conducted.The results showed that increasing the waterproof curtain depth of the foundation pit can effectively protected the subway structure around the foundation pit.