塑料排水板结合真空预压法的径向固结解析解

Radial Consolidation Solution of Plastic Wick Drain Combined Vacuum Preloading

塑料排水板结合真空预压的软土地基加固方法是一种经济高效并被逐渐广泛应用的地基加固方法,该方法不仅可以减少堆载预压坝体的高度,还能减少土体的侧向位移.推导的塑料排水板与真空预压结合的非线性径向固结解析解可以较好地用于该种地基加固的预测和分析.求解过程认为软土在一维固结条件下孔隙比与平均有效应力、水平渗透系数成对数线性关系,而非以前认为的一维线性关系,因排水板周围土体被扰动,所以涂抹区中水平渗透系数采用抛物线分布形式,同时还考虑真空预压对固结的作用.退化提出的解析解与前人解析解进行对比验证、完成解析解与试验结果验证,证明了该解析解的正确性.最后,分析了参数κ和C_k/C_c对固结的影响,结果表明C_k/C_c值越大,固结时间越短,κ值增大,固结时间增长.

A system of radial consolidation by combining the plastic wick drain with the vacuum preloading is one of the most popular way for soft ground improvement, which can not only reduce the height of surcharge preloading on dam, but also reduce the lateral displacement of soil. The consolidation solution of plastic wick drains and vacuum preloading based on the nonlinear relationship can well forecast and analyze this kind of ground improvement. In the process of analytical solution, the relationship between the void ratio and the mean effective stress, as well as the horizontal permeability coefficient under one-dimensional consolidation is considered to be semi logarithmic linear, rather than previously thought one-dimensional linear. Because of disturbing on soil around PVD in smear zone, permeability around PVD in the zone distributes in parabolic form. Besides, the effect of vacuum preloading on consolidation is taken into consideration. This analytical solution is verified through degradation method and compared with test results. Finally, the effects of κ, Ck/Cc are analyzed on consolidation. The results indicate that consolidation rate increases with the increasing of Ck/Cc and decreasing of κ.