A three-dimensional unified hardening model for anisotropic soils

Based on the UH (unified hardening) model a new anisotropic constitutive model for anisotropic soils is presented in a new anisotropic transformed stress space. An anisotropic peak strength M_α is firstly introduced to represent the inherent anisotropy associated with particles' orientation distribution. An anisotropic transformed stress tensor σ̃ _ij^a is proposed by incorporating M_αwith the original transformed stress tensor σ̃_ij. The failure criterion and the stress-strain relationship for anisotropic soils are interpreted in the same constitutive framework. The capabilities of the proposed model are illustrated through comparisons of model simulations with experimental data. The basic soil parameters can be determined from the conventional triaxial compression tests on vertical specimens and horizontal specimens.