Analysis of elastic viscoplastic consolidation of sand drain foundations with exponential seepages

Abstract

Studies have shown that the pore seepage in soft clay deviates from Darcy's law, with the compressibility and permeability of the soil demonstrating obvious nonlinear characteristics during the consolidation process. These factors will affect the sand drain foundation consolidation process. In order to explore the consolidation mechanism of sand drain foundation in saturated clay, this paper introduces the UH model considering the time effect to describe the nonlinear deformation relation of the soil skeleton under the Barron free strain assumption and introduces the exponential seepage equation as an alternative to Darcy's law. Additionally, the impact of the permeability coefficient and the smearing effect is considered which is used to re-derive the conventional sand drain consolidation equation, and then the finite difference method is adopted to give the implicit numerical solutions of the equation. By comparing with literature results, the validity of the method developed in this paper is verified. Then, the effects of the soil nonlinearity, construction disturbance, and external load on the sand drain foundation nonlinear consolidation process are studied as a function of time. The current results reveal that due to the viscous effect of soil, the pore pressure near the undrained boundary of the sand drain foundation during the pre-loading period increases. The above phenomenon is more evident when considering the non-Darcy seepage; meanwhile, the consolidation rate of the sand drain foundation also becomes increasingly slow. Moreover, the decrease of the permeability coefficient in the smear zone can significantly reduce the dissipation rate of the overall pore pressure of the sand drain foundation, while the increase of the external load accelerates foundation consolidation.

Research on Nanoeffect of Penetration and Consolidation under Nonlinear Characteristics of Saturated Soft Clay

“…For example, in terms of research ideas, the comprehensive effects of gravity water, capillary water, and weakly binding water under the action of different hydraulic gradients have been considered, the structure of cohesive soil has been considered, and the permeability coefficient of rock and soil mass has been regarded as a random variable to analyze the seepage condition of the soil layer, etc. [ 2 , 3 ]. Some studies have been improved continuously from the aspect of test instruments.…”