ONE-DIMENSIONAL RHEOLOGICAL CONSOLIDATION ANALYSIS OF SATURATED CLAY CONSIDERING VARIABLE PERMEABILITY

To further investigate the effect of elastic visco-plasticity and variable permeability of saturated clay on one-dimensional consolidation process, we introduced the unified hardened(UH) constitutive model considering time effect to describe the elastic visco-plasticity of saturated clay, and used Taylor's empirical relation to describe the relationship between its permeability coefficient and void ratio. Then we modified Terzaghi's one-dimensional consolidation theory, and employed the finite difference solution format. By comparing the numerical solutions with the results of one-dimensional rheological consolidation test, we verified the effectiveness of the proposed method and the applicability of the UH model. Base on this, we investigated the effects of parameters of UH model, the ratio of compression index to permeability index and the load intensity on the consolidation process. Numerical results indicate that the viscosity of saturated clay makes the pore pressure rise in the early stage of consolidation, slows down the overall dissipation of pore pressure in the middle and late stage of consolidation, and increases the settlement of soil layer. This phenomenon is more obvious with the increase of the initial overconsolidation parameters. In addition, with the decrease of the ratio of compression index to permeability index, the consolidation process of soil layer will be accelerated, but the final settlement will not be affected by the ratio. In the later stage of consolidation, the pore pressure dissipation in the soil layer with less load is slower if the compression index is not greater than the permeability index. However, the effect of the load intensity on the pore pressure dissipation is relatively small if the compression index is larger than the permeability index.