浅埋暗挖地铁隧道引起地表沉降的数字模拟与实测分析

Digital Simulation and Experiment Analysis of Ground Subsidence Caused by Shallow-buried Metro Tunnel Excavation

地铁隧道施工引起地表沉降问题是地铁隧道建设最难控制且亟待解决的关键性问题之一。根据土体变形机理,对我国北部某城市浅埋暗挖地铁隧道开挖地表沉降量进行有限元预测计算,并利用施工路段现场监测值对模拟结果进行验证。验证结果表明:应用有限元软件模拟计算得到最大竖向沉降量产生在隧道轴线正上方位置,施工结束后的最大沉降值约为39.9 mm;实际监测MS-6断面施工结束后的最大沉降值为55.1 mm;实测值与模拟计算值存在一定差异,距离隧道轴线位置越近,两者差异的数值越大。实测地表沉降值与模拟计算值整体变化一致,因此应用有限元模拟浅埋暗挖地铁隧道引起地表沉降量是可行的。

Ground subsidence caused by metro tunnel construction is one of the most uncontrollable and key issues to be solved urgently.According to the deformation mechanism of soil,the ground subsidence volume of shallow-buried metro tunnel excavation in a northern Chinese city is predicted with finite element calculation,the simulation results of which are verified with the monitored data of on-site construction.The results show that the maximum vertical foundation settlement takes place right above the tunnel axis and the maximum settlement value is around 39.9 mm after the construction based on the finite element software simulation.While the maximum settlement value monitored right after the construction of MS 6 section is 55.1 mm.There is a difference between the simulated and the on-site monitored data,the amount of which increases as further approaching the tunnel axis position.Since the measured ground subsidence value is consistent with the overall change of the simulated one,it is feasible to use finite element to simulate the surface subsidence caused by shallow-buried underground subway tunnel.