A constitutive model for sand liquefaction under rotational shear

Recently, the undrained anisotropic behavior of sand subjected to rotational shear has been a subject of great interest in both fields of experimental studies and constitutive modeling. Herein, based on the critical state concept and the bounding surface plasticity framework, a unified sand model is presented that is able to simulate the liquefaction of sand subjected to various stress paths, especially rotational shear. Using two anisotropy state parameters, the effect of soil anisotropy on the location of critical state line, dilatancy, plastic modulus, and flow direction is considered in constitutive equations. Finally, the simulative capability of the presented model is illustrated by comparison with the experimental data reported by independent research teams over a wide range of densities, stress paths, and stress levels.