Nonlinear Cross-Anisotropic Model for Soils at Various Strain Levels

Abstract

Nonlinearity and anisotropy of stress-strain responses are important factors influencing the behavior of soil. To describe this complex behavior of soils, a hypoelastic constitutive model is developed based on cross-anisotropic elasticity, which involves four parameters: the bulk modulus, tangent Young’s modulus, coefficient of volume deformation, and Poisson’s ratio. To satisfactorily predict the stiffness of soils at various strain levels, especially in small strain regions, a new stress-strain fitting relationship with four parameters is proposed. For normally consolidated or weakly overconsolidated clay, the dilatancy equation of the Cam-clay model is used to determine the coefficient of volume deformation. Overall, the model is convenient to use. Ten material parameters are involved, which can be obtained from an isotropic compression test, a set of drained triaxial compression tests, and a uniaxial compression test. The computed results of the model are in good agreement with the data from the tests, in which each specimen was reconsolidated under the