基于修正莫尔库伦的基坑开挖对隧道安全影响研究

Research on influence of foundation pit excavation on tunnel safety based on modified Mohr Coulomb

为分析基坑开挖对临近地铁隧道的影响,以某基坑工程为研究背景,结合修正-莫尔库伦本构关系,采用Midas GTS NX构建三维地层结构模型,通过仿真分析基坑开挖前后隧道水平、竖向位移的变化规律及特征点。结果表明:基坑开挖会导致地铁隧道结构产生水平收缩的趋势,隧道最大沉降和隆起点从远离基坑的外侧隧道向靠近基坑的内侧隧道转移;同时,还明确变形的最大位置,得到隧道最大隆起和沉降截面处的变形规律,构建“O”型和“S”型竖向变形模型,研究结果可为基坑开挖条件下的地铁隧道安全分析提供参考,对地铁隧道的保护具有一定意义。

In order to analyze the influence of foundation pit excavation on the adjacent subway tunnel,taking a foundation pit engineering as the research background,and combined with the modified Mohr Coulomb constitutive relation,the Midas GTS NX was used to build a three-dimensional stratum structure model,and the variation law and characteristic points of horizontal and vertical displacement of tunnel before and after the foundation pit excavation were analyzed by simulation.The results showed that the foundation pit excavation would lead to a horizontal convergence trend of the subway tunnel structure,and the maximum settlement and uplift points of the tunnel would transfer from the outside tunnel far away from the foundation pit to the inside tunnel near the foundation pit.At the same time,the maximum deformation position was determined,the deformation law of the maximum uplift and settlement section of the tunnel was obtained,and the“O”type and“S”type vertical deformation models were constructed.The results can provide reference for the safety analysis of subway tunnel under the condition of foundation pit excavation,and has a certain significance for the protection of subway tunnel.