考虑渗流影响的基坑变形规律与稳定性研究

以湖南常德沅江隧道明挖基坑工程为依托，基于流固耦合数值模拟方法研究土体渗透系数对基坑变形与稳定性的影响规律。结果表明:基坑在考虑渗流作用的数值计算结果与实际的监测变形值基本吻合，随着强渗透地层渗透系数的增大，基坑变形呈增大趋势，基坑底板安全系数呈十分明显的下降趋势，且渗透系数的改变对基坑底板隆起的影响较大，对墙后地表沉降和地连墙水平位移的影响较小；进一步对比分析了考虑与不考虑渗流作用的基坑底板安全系数变化规律，在此基础上建立了考虑渗流作用的安全系数经验公式。

Deformation Law and Stability of Foundation Pit Considering Seepage Effect

Based on the open excavation project of Yuanjiang tunnel in Changde, Hunan province, the influence law of soil permeability coefficient on the deformation and stability of the foundation pit was analyzed based on the numerical simulation method of fluid-solid coupling. The results show that the numerical calculation results of foundation pit deformation considering seepage action are basically consistent with the actual monitoring values. With the increase of the permeability coefficient of the strongly permeable stratum, the foundation pit deformation presents an increasing trend, and the safety coefficient of foundation pit floor presents an obvious downward trend. Moreover, the change of permeability coefficient has great impacts on the uplift of foundation pit floor, but small impacts on the surface settlement behind the wall and the horizontal displacement of the ground wall. Furthermore, the variation law of safety coefficient of foundation pit floor with and without considering the seepage effect is compared and analyzed, and the empirical formula of safety coefficient considering seepage effect is established on this basis.