真空联合堆载预压下基于指数形式渗流的砂井地基非线性固结解

ANALYTICAL SOLUTION FOR NONLINEAR CONSOLIDATION OF SAND-DRAINED GROUND WITH EXPONENTIAL FLOW UNDER VACUUM COMBINED SURCHARGE PRELOADING

基于指数形式渗流定律,通过引入e-lgσ′和e-lgk模型来考虑土体的非线性固结特性,同时考虑了真空负压沿深度呈线性衰减的特性,对真空联合堆载预压下砂井地基的固结问题进行了求解,并推导得到了砂井地基的非线性固结解。通过将该文解析解答与已有的解析解展开对比分析,验证了该文解答的正确性。根据该文解答,对砂井地基的固结性状展开了分析,分析表明:在固结初期,渗流指数m越大,砂井地基的固结速率越快;但在固结后期,m越大,砂井地基的固结速率越慢;负压传递系数kz对砂井地基固结速率的影响较小,但kz的减小会使得砂井地基的沉降速率和最终沉降量降低;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;当m<1时,外荷载越大,砂井地基的固结速率越小;当m>1时,外荷载越大,砂井地基的固结速率越大。

Based on an exponential flow law for soft soil,e-lgσ′and e-lgk logarithmic models are introduced to consider the nonlinear consolidation characteristics of soil,the characteristics of the vacuum negative pressure decreasing along the depth are also considered,and an analytical solution for nonlinear consolidation of sanddrained ground is derived under vacuum combined surcharge preloading.By comparing the analytical solution with the existing one,the correctness of the analytical solution is verified.According to the analytical solution,the consolidation behaviors of sand-drained ground are analyzed.The analysis shows that in the initial stage of consolidation,the larger the flow index m,the faster the consolidation rate of sand-drained ground,but in the later stage of consolidation,the larger m is,the slower the consolidation rate of sand-drained ground is.The negative pressure transfer coefficient kz has little effect on the consolidation rate of sand-drained ground,but the decrease of kz will reduce the settlement rate and final settlement of sand-drained ground.The higher the ratio of compression index to permeability index,the slower the consolidation rate of sand-drained ground is.When m<1,the larger the surcharge loading,the smaller the consolidation rate of sand-drained ground;When m>1,the larger the surcharge loading,the higher the consolidation rate of sand-drained ground.