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

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 sand-drained 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 k_z has little effect on the consolidation rate of sand-drained ground, but the decrease of k_z 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.