Elastic viscoplastic constitutive model for K₀-consolidated soft clays

A new anisotropic elastic viscoplastic(EVP) constitutive model was presented for K0-consolidated soft clays in general stress space.It was assumed that two surfaces existed for any loading history: dynamic loading surface and reference yield surface,both of them are nonsymmetrical ellipses with inclination defined by anα-line.The flow function was established by the visco-plastic volumetric strain rate under one-dimensional condition,the secondary compression coefficent was directly used to describe the rate effects.All model parameters could be easily gained from the results of one-dimensional compression tests and triaxial undrained shear tests.With the determined parameters,the anisotropic EVP model was used to simulate the behaviors of the triaxial undrained constant axial strain rate compression tests and undrained creep tests of some representative clays,it was demonstrated that the calculated results agreed with the test data well,and the present anisotropic EVP model was effective and feasible.