考虑指数流的真空预压竖井地基固结解析解

Analytical solution for consolidation by vertical drains with exponential flow under vacuum preloading

传统固结理论认为渗流速度和水力梯度呈线性关系,但在软塑性土地基中常出现背离线性关系的情况,即为非达西渗流模式。在经典竖井地基固结理论的基础上,假设孔隙水渗透服从指数渗流模式,并结合真空预压的边界条件,建立新的竖井地基固结计算模型,获得超静孔压和径向固结度的严格解答,并通过开展多工况算例对比,分析指数渗流模型参数和真空压力沿竖井衰减系数等对竖井地基固结计算结果的影响效应。研究结果表明:非达西渗流指数m对固结速率影响最为显著,在固结初期,m越大,固结速率越快;在固结后期,m越小,固结速率越快;涂抹区参数s及κh/κs越大,竖井地基固结速率越慢;负压衰减系数k1和k2、真空荷载p0越大,固结速率越快。

According to the traditional consolidation theory, the velocity of flow v is linearly related to the hydraulic gradient. But the case is not true with high plastic clay. On the basis of the traditional and classic consolidation theory of vertical drains, supposing that v is exponentially related to i, and taking into consideration the boundary conditions of the vacuum preloading, a new consolidation computation model of vertical drains was established and the corresponding solution of excess pore water pressure and radial degree of consolidation was obtained exactly. Based on the solution, the consolidation behavior of the vertical drained ground with exponential flow was investigated by parameters study. The results show that the non-Darcian flow exponent has the most important influence on consolidation rate. In initial stages of consolidation, the increase of m can accelerate the consolidation rate and make the consolidation rate slow down in the later stage. The increase ofs and kh/ks can make the consolidation rate slow down. The increase of the vacuum reduction factors kl, k2 andp0 can raise the consolidation velocity.