SANICLAY-T: simple thermodynamic-based anisotropic plasticity model for clays

In this work the anisotropic model for clays SANICLAY proposed by Dafalias and Taiebat (2013) is reformulated within the framework of hyper-elastoplasticity. The model, called SANICLAY-T, is fully defined by two scalar potential functions, the free energy and the rate of dissipation. It is first presented in the triaxial space and then generalised in the multiaxial one. The model reproduces exactly the original one for the case of associate flow rule, while leads to a different outcome for non-associated flow. When compared to existing hyperplastic models accounting for rotational hardening, the proposed one proves to be more versatile, as characterised by less restrictive constraints on the hardening and asymptotic behaviour of the soil. The predictive capability of the model is illustrated with reference to experimental data on natural and reconstituted clays, highlighting its merits and limitations.