Evolution of sand crushability and its effect on particle-scale energy allocation

Detailed knowledge of crushability evolution and particle-scale energy allocation behavior under the influence of particle breakage is of fundamental importance to the development of micromechanics-based constitutive models of sands. This paper reports original results of the breakage development and energy input/dissipation of idealized crushable sands using 2D DEM simulations. Particle breakage is modeled as the disintegration of synthetic agglomerate particles which are made up of parallel-bonded elementary discs. Simulation results show that the initial specimen density and crushability strongly affect the energy allocation of the soil both at small and large strains. The major role of particle breakage, which itself only dissipates a negligible amount of input energy, is found to advance the soil fabric change and promote the inter-particle friction dissipation. Particularly, at small strains, particle breakage disrupts the strain energy buildup and thus reduces the mobilized shear strength and dilatancy of a granular soil. At large strains where particle breakage is greatly reduced, a steady energy dissipation by inter-particle friction and mechanical damping is observed. Furthermore, it is found that the amount of particle breakage keeps increasing during the whole shearing process, but the rate of particle breakage decreases gradually with the applied axial strain. © 2013 AIP Publishing LLC.