Identification of Local Mechanisms in Clays and Energy-Based Modelling

The paper addresses the issue of how physical-chemical aspects affect the mechanical behaviour of clays and how they could be integrated in the mechanical modelling. A significant influence of the high-plastic-clay fraction on the behaviour of clayey materials was experimentally highlighted, such as the compression index variation, or the strong and very marked decrease of friction angle. Microstructural investigation provides further understanding allowing to relate the observed phenomena to an activated mechanisms acting at the level of clay particles. A new approach using the Chang and Hicher micromechanical model was proposed, where physical-chemical effects, acting between clays clusters, are incorporated. Local mechanisms are introduced through repulsive and attractive forces obtained from the derivation of energy potentials.