考虑土体渗透性径向变化的砂井地基数值模拟分析

土体渗透性是影响砂井地基固结的重要因素。为研究复杂条件下砂井地基的固结性状，通过编制用户子程序在ABAQUS中建立了渗透系数沿径向变化的砂井地基固结计算数值模型，对固结过程中的孔压分布及固结性状进行了研究。结果表明:渗透系数在径向上的变化情况会对砂井固结性状产生很大的影响。假定涂抹区渗透系数为常数时固结速率最慢；假定涂抹区渗透系数呈抛物线变化时固结速率最快；而假定涂抹区渗透系数呈线性变化时固结速率介于以上两种情况之间。此外，砂井地基的固结性状还受排水条件和土层特性等因素的影响。

Numerical Simulation of Sand Drains Foundation with a Consideration of Permeability Coefficient Changing along the Radial Direction

The permeability of soil is an important factor which affects sand drain foundation consolidation. To analyze the consolidation behavior of sand drain foundation under complex conditions, user subroutine is programmed in ABAQUS to set up a numeric calculation model of sand drain foundation consolidation whose permeability coefficient changes along the radial direction. The pore pressure distribution and consolidation behavior during the process of consolidation are also analyzed. The results show that the changes of permeability coefficient along the radial direction have a big effect on the consolidation behavior of sand drain foundation. When assuming the permeability coefficient of smear zone constant, the degree of consolidation is slowest. When assuming the permeability coefficient of smear zone changes in shape of a parabola, the degree of consolidation is fastest. When assuming the permeability coefficient of smear zone changes in a linear fashion, the degree of consolidation is between the degrees of two situations above. Besides, the consolidation behavior of sand drain foundation is also affected by drainage condition and soil properties.