真空预压法加固软基三维有限元计算

为预测广州南沙港区某真空预压加固工程的效果与影响范围,针对真空预压加固大面积软基的变形特点,提出将单井涂抹效应对涂抹区内土体渗透性的弱化作用转化为减小单井影响区内土体水平向渗透系数的方法,既可减少三维有限元计算的前处理工作量,又可考虑砂井地基的涂抹效应,讨论了网格尺寸对固结度的影响。并视土体为多孔介质,采用比奥固结理论,结合依托工程,建立了较大规模的三维模型并进行有限元计算分析,计算结果与现场监测数据吻合得较好。

Analysis of 3D FEM for soft foundation improved by vacuum preloading

To predict the effects and influence circle of a soft foundation improved by vacuum preloading in Nansha Port of Guangzhou, according to the deformation characteristics of large area soft foundation improved by vacuum preloading , the method which considers the smear effects diminishing the permeability of the soil in the smear zone can be transformed into the reduction on horizontal permeability coefficient of the soil in the effective zone, is presented based on the equivalent consolidation degree. The pre-processing work of 3D FEM can be reduced and the smear effects are taken into account, and the influence on the consolidation degree induced by the size of element is discussed. Regarding soil as porous media and combining the project of vacuum preloading in Nansha Port of Guangzhou, a large-scale 3D FEM model is set up and the numerical calculation is executed with Biot consolidation theory. The calculated results agree well with the monitored data in situ.