考虑井阻随时间变化下砂井地基的非线性固结解

针对砂井地基固结过程中砂井的渗透系数会逐渐降低这一特性,通过引入e-lg??和e-lgk对数模型来描述土体的非线性固结特性,同时考虑井阻随时间变化和涂抹区径向渗透系数变化等因素,推导砂井地基非线性固结的控制方程,并采用分离变量法求得该方程的固结解。通过退化研究并与已有的解析解进行对比分析,对该解答的正确性进行验证。基于该解答,对砂井地基的非线性固结性状进行分析。分析表明:砂井地基的固结速率随井阻因子的增大而减小,井阻的变化主要对砂井地基后期固结速率的影响较大;在涂抹区径向渗透系数变化的3种模式中,抛物线变化模式固结速率最快,线性变化模式次之,常数变化模式固结速率最慢;压缩指数与渗透指数的比值越大,砂井地基的固结速率越慢;在非线性压缩关系下,砂井地基固结过程中的平均孔压固结度始终慢于平均沉降固结度。

Analytical solution for nonlinear consolidation of sand-drained ground considering time-dependent well resistance

Aiming at that the permeability coefficient of sand drains will gradually decrease in the consolidation process of sand-drained ground,e-lg??and e-lg k logarithmic models are introduced to describe the nonlinear consolidation characteristics of soils in this paper,and considering the time-dependent well resistance and the variation of the radial permeability coefficient in the smear zone,a governing equation for nonlinear consolidation of sand-drained ground is derived and the corresponding analytical solution is obtained by using the separation variable method.The correctness of the solution is verified by the degradation study and the comparative analysis with the existing analytical solution.Based on the analytical solution,the nonlinear consolidation behaviors of sand-drained ground are investigated.The results show that the consolidation rate of sand-drained ground decreases with increasing the well resistance factor,and the time-dependent well resistance mainly affects the consolidation rate in the later stage.Among the three change modes of the radial permeability coefficient in the smear zone,the parabolic mode has the fastest consolidation rate,followed by the linear mode and then the constant mode.The higher the ratio of the compression index to the permeability index,the slower the consolidation rate of sand-drained ground.Under the nonlinear compression relationship,the average consolidation degree defined by the pore pressure is always slower than the average consolidation degree defined by the settlement in the consolidation process of sand-drained ground.