软土地区盾构法隧道施工三维数值模拟

本文采用三维有限元方法,考虑软土的固结作用和隧道开挖与周边建筑物变形的相互作用,对隧道施工的全过程进行数值模拟,分析盾构法隧道施工对周边建筑物的影响。数值计算结果表明:在考虑流固耦合的条件下,盾构法隧道开挖时3～4倍洞径范围内的土体变形可能会超过土体位移的规范规定值,施工中应加强该距离范围内的土体和周边建筑物的监测;盾构法仅对开挖掌子面处附近局部区域的孔隙水压力有影响,说明软土地区盾构法隧道施工对地下水的扰动很小;通过监测数据与计算值的对比分析可以得出,典型监测点的变形规律与监测规律相同,说明在工程条件相似的软土地区采用数值模拟对盾构法隧道施工进行预测和仿真分析是可行的,具有一定的工程参考价值。

3D Numerical Simulation of Excavation of Shield Tunnel in Softground

Three-dimensional finite element method was used to simulate the whole process of the tunnel construction,to analyze the impact of shield tunnel construction on surrounding buildings.During the process of analysis,the consolidation effect and the interaction of tunnel excavation and the deformation of surrounding buildings were taken into consideration.Numerical results show that: in considering the conditions of fluid-structure interaction,the deformation of the soil within 3 to 4 times of tunnel diameter may exceed the value of the specific displacement.The monitoring of soil and surrounding buildings within this range should be intensified.Shield tunnel construction influences the pore water pressure near the working face which means the groundwater disturbance of shield tunnel construction in soft tunnel is very small.The computed deformation law of typical point was the same to that of the monitoring point,which means that it is possible to forecast and simulate the process of shield tunnel construction in the similar soft clay area.The study is a valuable reference for simulation of shield tunnel construction in area of softground.