考虑变荷载和土体非线性的真空预压竖井地基固结解

针对真空预压竖井地基固结问题,考虑地基土体的非线性、涂抹区土体水平向渗透系数呈抛物线变化和荷载随时间变化的影响,推导出真空预压条件下竖井地基固结的一般解。通过退化研究和对比分析,验证了解析解的合理性。基于一般解,得出瞬间加载和线性加载两种特殊加载模式的相应特解。针对特解,编制计算程序,绘制出真空预压竖井地基固结过程曲线。结果表明,土体非线性对固结特性有较大影响,压缩指数与水平向渗透指数比值越大,地基固结速率越慢;初始应力值越大,土体的固结速率越快;线性加载下竖井地基孔压消散速率较瞬时加载慢。

Analytical solution for foundation consolidation of vacuum preloading vertical drain considering variable load and nonlinearity of soil

Aiming at the foundation consolidation problem of vertical drains under vacuum preloading,considering the influence of nonlinear of foundation soil and the parabolic variation on the horizontal permeability coefficient of the smearing area and loading changes with time,we derive a general solution of vertical drain consolidation under vacuum preloading,and verify the rationality of the analytical solution by the study of degradation and comparative analysis.Based on this general solution,we obtain the corresponding special solutions of two special loading modes for instantaneous loading and linear loading,compile the calculation program,and draw the curves of the consolidation process of the vacuum preloading vertical drain according to the special solution.The results show that the nonlinear of foundation has a great effect on the consolidation characteristics.The greater the ratio of the compressibility index to the horizontal permeability index is,the slower the consolidation rate of the foundation is.The greater the initial stress is,the faster the consolidation rate of the soil is.The vertical drain pore pressure dissipation rate under linear loading is slower than that of the instantaneous loading.