A strain hardening model for rockfills

Not only the strength and stiffness varies with stress level, the volumetric change of rockfills under shearing also depends on the confining pressures. A strain hardening model based on Mohr-Coulomb model is proposed for simulation of the shearing characteristics of rockfills. This model utilizes Mohr-Coulomb yield criterion with full consideration of the stress-dependence of stiffness, shearing strength and dilatancy. The theoretical development and experimental base of Rowe's dilatancy theory is assessed in details, with its limitation for rockfills highlighted. Modification is then made to derive the mobilized dilatancy angle of rockfills. Compared with large triaxial testing results, it has been demonstrated that this new model is capable of simulating the shearing characterizations of granular soils, specially the volumetric changes, despite of its simplicity.