基于渗流场-应力场耦合作用的基坑土体变形特性研究

对渗流场-应力场耦合理论及耦合作用下土体固结特性进行分析,建立耦合作用下有限元方程及有限元模型。从理论联系实际的角度出发,利用岩土有限元分析软件PLAXIS对某采用复合土钉支护方案的基坑工程进行有限元模拟分析,分别建立不考虑渗流场影响及考虑渗流场-应力场耦合作用的2种计算模型,模拟分步开挖时复合土钉支护结构下基坑土体变形特性,并对2种模型计算结果进行对比分析,通过模拟结果与现场实测数据的对比,结果表明耦合作用下的基坑土体变形计算值与现场实测值较为一致。说明考虑渗流场-应力场耦合作用下的有限元数值模拟方法是可行的,计算结果是合理的,对类似工程具有一定的指导意义。

The coupling theory of seepage field and stress field and the consolidation characteristics of soil under coupling are analyzed,and the finite element equation and finite element model under coupling are established.From the point of view of combining theory with practice,the finite element simulation analysis of a foundation pit with composite soil nailing is carried out by using geotechnical finite element analysis software PLAXIS.Two calculation models without considering the influence of seepage field and considering the coupling effect of seepage field and stress field are established respectively,and the soil deformation characteristics of foundation pit under composite soil nailing structure during step-by-step excavation are simulated.The calculation results of the two models are compared and analyzed.The simulation results are compared with the field measured data.The results show that the calculated value of foundation pit soil deformation under the coupling action is consistent with the field measured value.It is shown that the finite element numerical simulation method considering the coupling of seepage field and stress field is feasible,the calculation results are reasonable,and has a certain guiding significance for similar projects.