Hypoplastic Model for Clays with Stiffness Anisotropy

Abstract

The Intergranular Strain Anisotropy (ISA) model by Fuentes and Triantafyllidis (2015) corresponds to an extension for the conventional hypoplastic models to account for the effects observed under cyclic loading. Similar to the Intergranular Strain (IS) theory proposed by Niemunis and Herle (1997), this extension enhance the hypoplastic models in many aspects as increasing the stiffness and reducing the plastic strain rate on cyclic loading. The present work is devoted to extend and evaluate a constitutive model for anisotropic clays under cyclic loading. The reference model corresponds to the anisotropic hypoplasticity for clays by Mašín (2014), which accounts for an elastic tensor depending on the bedding plane’s orientation. The proposed model results from extending the hypoplastic model with ISA. For validation purposes, different simulations under monotonic and cyclic loading were performed with an anisotropic kaolin clay. It was found that the proposed model accurately predict the experimental results under a wide range of strain amplitudes.