Discrete element method and thermodynamics with internal variables: two complementary approaches to link micro- and macro-scale modelling of anisotropic clays

This paper presents some preliminary results of a multiscale approach based on the complementary use of the Discrete Element Method (DEM) and the Thermodynamics with Internal Variables (TIV) to model anisotropy of clays. Within this framework, two internal variables, namely porosity and fabric, describe the main features of clay mechanics and keep track of their evolution. In this perspective, DEM results allow to identify an efficient calibration procedure of the microscale model parameters, and to validate the ability of the thermodynamics-based formulation to account for the evolving elastic stiffness anisotropy of clays along different loading paths.