基于流固耦合效应的深基坑降水开挖变形规律研究

Research on Deformation of Deep Foundation Pit Dewatering Excavation Based on Fluid-solid Coupling Effect

以武汉时代广场深基坑项目为依托,运用ABAQUS有限元数值软件建立仿真模型,对比分析了基坑开挖流固耦合模型与非流固耦合模型基坑外地表沉降、基坑内土体隆起、双排桩水平位移和孔隙水压力规律。结果表明:(1)流固耦合模型与非流固耦合模型基坑外地表沉降规律大致相同,但是流固耦合模型的沉降位移量要大于非流固耦合模型的沉降量;(2)基坑开挖阶段考虑地下水影响的基坑底部土体隆起量要小于不考虑地下水影响的基底隆起量;(3)由于地下水的影响,流固耦合模型的双排桩水平位移值明显大于非流固耦合模型中双排桩的水平位移值;(4)由于支护结构的止水作用使得基坑内部土体的孔隙水压力变化较大,而基坑外部土体孔隙水压力变化则相对不明显。

Based on Wuhan Times Square deep foundation pit project,the ABAQUS finite element numerical software is used to establish a simulation model,and the fluid-solid coupling model and the nonfluid-solid coupling model of foundation pit excavation are compared and analyzed.The surface settlement outside the foundation pit,the soil uplift in the foundation pit,horizontal displacement and pore water pressure of double-row piles are studied.The results show that:(1)the settlement rules of the fluid structure coupling model and the non fluid structure coupling model are basically the same,but the settlement displacement of the fluid structure coupling model is larger than that of the non fluid structure coupling model;(2)the soil uplift at the bottom of the foundation pit considering the influence of groundwater in the excavation stage is smaller than that of the basement without considering the influence of groundwater;(3)due to the influence of groundwater influence,the horizontal displacement value of double row piles in the fluid structure coupling model is significantly greater than that in the non fluid structure coupling model;(4)because of the sealing effect of the support structure,the pore water pressure of the soil inside the foundation pit changes greatly,while the pore water pressure of the soil outside the foundation pit changes relatively little.