An Anisotropic Critical State Plasticity Model with Stress Ratio-Dependent Fabric Tensor

This paper proposes a new constitutive model within the recent anisotropic critical state theory (ACST) to take into account the influence of evolving fabric on the stress-strain-strength response of anisotropic sands. Analytical proofs in support of stress-force-fabric correlations corroborate a clear connection between mobilization of the continuum level stress ratio and particle level fabric in granular media. A normalized stress ratio-dependent second-order fabric tensor is suggested here which fulfills the ACST. Dilatancy and plastic hardening modulus of a stress ratio-driven elastoplastic model with zero pure elastic domain are explicitly interrelated to the proposed stress ratio-dependent normalized fabric tensor. It is shown that the fabric-dependent model simulations agree well with the monotonic triaxial and hollow cylinder torsion shear tests data.