Nonlinear Permeability Characteristics of Shanghai Clay and Their Influence on Embankment Deformation

The relationship between permeability and deformation of Shanghai clay has rarely been reported, and the influence of the variation of hydraulic conductivity with deformation on embankment deformation is not clear. Multiple sets of permeability testswere conducted on Layer 8 in Shanghai, China, and then a nonlinear relationship between hydraulic conductivity and void ratio of Shanghai clay was established comprehensively. Furthermore, this relationship was implemented in the commercial software program, and the differences in simulated deformations with and without considering the variation were investigated and validated. The results indicate that hydraulic conductivity and void ratio decrease nonlinearly with the increase of hydraulic gradient. The formula form of lge−lg[k(1 + e)] can better simulate the relationship between hydraulic conductivity and void ratio of Shanghai clay compared to other forms. The embankment deformations obtained by considering the variation are smaller than those obtained without considering it due to the increase in excess pore-water pressure and decrease in effective stress, hydraulic conductivity, and the degradation rates of overconsolidation and soil structure. The results obtained by considering the variation in the deformation calculation of embankment on coastal soft clay are in good agreement with the field-measured data; otherwise, it will cause an overestimation.