A new elasto-plastic model with consideration of grain breakage

A new model taking into account grain breakage influence is developed within the framework of elasto-plasticity and the critical state theory. The model aims at describing the behaviour of soils with grain crushing under shearing. Grain crushing induces mainly a decrease of the maximum shear strength and an increase of the material contractancy. The yield function is a Mohr-Coulomb criterion in which a hyperbolic hardening function of the plastic deviatoric strain is added. The main assumption of this model is that, upon loading, the void ratio at critical state changes as the consequence of the changes in the properties of materials, clue to grain breakage. The effect of the grain size distribution is introduced in the relationship between the void ratio at critical state and the mean effective stress. Some triaxial experiments were performed on crushable granular materials. The comparison of experimental results and model predictions shows that this model can well reproduce the behaviour of granular materials subjected to grain breakage.