DEM study on the microscale and macroscale shear behaviours of granular materials with breakable and irregularly shaped particles

Existing DEM researches related to particle breakage usually assume that particles are regular shapes and debris is spherical. In this paper, a method combining relatively realistic particle shape and realistic breakage is proposed to study particle breakage in the DEM. The particle morphology was derived from the scanned real particles and was convex treated. The breakable particle was modelled as an aggregate composed with coplanar and glued Voronoi polyhedra. Then, a series of drained triaxial tests under different confining pressures were conducted. The macroscopic characteristics, including the shear strength, dilatancy and particle breakage, are qualitatively in agreement with previous literatures, which show the rationality of the proposed method. Further, the microscopic characteristics, including the coordination number and sliding contact, were investigated to explore the effect of particle breakage on the macroscopic shear behaviour. Finally, the analysis-related anisotropy coefficients were evaluated to probe the microscopic origins of the peak and critical shear strengths.