Investigating the effects of elongation and flatness on the shear behaviour of breakable granular materials via the DEM

摘要

Abstract Particle shape is a vital factor affecting particle breakage and mechanical behaviour of granular materials. This report investigated the effect of elongation and flatness on the shear behaviour of breakable granular materials using the DEM. Rod-shaped and discoid models were used to model various elongated and flat particles. A breakable particle is constructed as an aggregate composed of coplanar and glued Voronoi polyhedra. After isotropic compression and drained triaxial compression tests, the macroscopic shear behaviours, including the shear strength and dilatancy response, were analyzed. Meanwhile, the particle breakage characteristics, including the evolution of particle size distribution curves, the extent of particle breakage and the correlation of relative breakage with energy input, were explored Furthermore, the evolutions of microscopic shear behaviours, including mechanical coordination number and contact force of assemblies with different elongation and flatness was evaluated. Finally, exploration of the related-anisotropy coefficients was carried out to probe the microscopic origins of macroscopic behaviour. A detailed analysis revealed the microscopic mechanism of the dependence of the peak and critical shear strengths on elongation and flatness.Graphic abstract