真空预压加固大面积地基有限元计算分析

竖向排水体的存在，使得对真空预压加固大面积地基进行三维有限元计算的工作量非常庞大。从宏观意义上讲，打设竖向排水体只是增加了加固区土体的竖向渗透系数。利用考虑井阻和涂抹作用的等效渗透系数计算公式，可将大面积真空预压加固区转化为等效地基，从而大大减少了单元数目。利用该方法对广州南沙港某一试验区进行三维有限元数值计算，并与实测值进行了对比。研究结果表明，采用等效渗透系数进行三维有限元计算是可行的，且计算精度可以满足工程要求。

Calculation and Analysis of Large-area Soft Ground under Vacuum Preloading

The workload of 3-D FEM calculation of large-scale soft foundation by vacuum preloading is tremendous because of prefabricated vertical drains(PVDs).On a macroscale,the effect of installing PVDs in a subsoil is to increase the mass hydraulic conductivity of the subsoil in the vertical direction.The large-scale ground by vacuum preloading can be transformed to the equivalent foundation by the equation of equivalent permeability coefficient which takes the well resistance and smear effects into account,so the amount of elements will be reduced largely.By means of this method,the 3-D numerical simulation of the test area at Guangzhou Nansha Port is executed,and the results are compared with the test data.It is shown that the 3-D calculation by FEM with the equivalent permeability coefficient is feasible and the calculating precision can meet the requirements of project.