Abstract: To further investigate the consolidation mechanism of saturated clay, the unified-hardening (UH) constitutive model considering the time effect was introduced to describe the elastic visco-plasticity of saturated clay soil as well as the Hansbo’s equation to describe the non-Darcy flow in the consolidation process. Accordingly, Terzaghi’s one-dimensional consolidation equation of saturated clay was modified, and the numerical analysis was conducted by using the finite difference method. In order to verify the applicability of the present method and the UH model, the numerical solutions provided by the present method for the cases that the flow of pore water obeys Darcy’s law were compared with the theoretical and experimental results based on one-dimensional rheological consolidation theory in the literature. Then the effects of Hansbo’s flow parameters and the UH model parameters on the rheological consolidation process were investigated. The calculation results show that the viscous effect of soil leads to an increase of pore water pressure near the impervious boundary at the early stage of consolidation, and the behaviour of the non-Darcy flow enhances this phenomenon. These two characteristics of soil also control the overall dissipation rate of excess pore water in the saturated clay layer, thereby reduce the settlement rates of the soil layer during the middle and late stage of consolidation. In addition, these aforementioned consolidation behaviours become more obvious with the increase of swelling index and overconsolidation parameter of soil. But the parameters of Hansbo’s flow and the permeability index have no effect on the ultimate settlement of the soil layer.

Key words: soil mechanics, saturated clay, rheological consolidation, Hansbo’s flow, elastic visco-plasticity, finite difference method, pore water pressure, ground settlement