软土地区桩锚联合支护基坑降水开挖的渗流应力耦合研究

RESEARCH ON COUPLING OF SEEPAGE AND STRESS IN DEWATERING AND EXCAVATION OF FOUNDATION PIT WITH COMBINED PILE AND ANCHOR SUPPORT IN SOFT SOIL AREA

基于某软土地区的桩锚联合支护的基坑项目,结合Midas GTS软件对该基坑进行渗流应力耦合作用下基坑降水开挖过程的三维建模,研究渗流应力耦合下基坑不同工况下的变形规律及支护结构位移变化情况,分析造成该基坑地表沉降及坑底隆起过大的原因。研究结果表明桩锚联合支护能够很好地约束软土基坑的侧向形变,但无法很好控制基坑内土体的竖向变形。结合模拟结果与实际工程情况进行对比分析,得出该基坑在不同降水开挖工况下的竖向变形主要是由于基坑地下水渗流作用导致,证明了在进行基坑支护设计时需要充分考虑渗流应力耦合作用。

Based on the foundation pit project of pile anchor combined support in a soft soil area,combined with Midas GTS software,the three-dimensional modeling of the foundation pit dewatering excavation process under the seepage stress coupling effect is carried out,the deformation law of the foundation pit under different working conditions and the displacement and internal force changes of the supporting structure under the seepage stress coupling effect are studied,and the causes of the ground settlement and the excessive uplift of the foundation pit bottom are analyzed.The research results show that the pile anchor combined support can restrain the lateral deformation of the soft soil foundation pit well,but it can not control the vertical deformation of the soil in the foundation pit.Combined with the simulation results and the actual engineering situation,it is concluded that the vertical deformation of the foundation pit under different dewatering excavation conditions is mainly caused by groundwater seepage,It is verified that the coupling effect of seepage and stress should be fully considered in the design of foundation pit support.