Numerical simulations of deviatoric shear deformation of granular media

Quasi-static shear deformation of granular media is examined by performing numerical simulations on polydisperse systems of elastic spheres in a periodic cell. Results of axisymmetric compression test simulations are reported for both a dense and a loose system. At the macroscopic scale, the simulated stress-strain-dilation responses are in excellent qualitative agreement with the mechanical behaviour of sand observed in real experiments. Numerical simulation permits a detailed examination of the evolution of internal variables associated with the micromechanical processes occurring at the particle scale. In this content, the evolution of the induced structural anisotropy, the percentage of sliding contacts, the average coordination number and the normal and tangential contact force contributions to the stress tensor are presented and discussed. Further simulations are reported which illustrate the effect of interparticle friction on both the macrocopic and microscopic mechanical behaviour. Finally, the versatility of numerical simulation is demonstrated by presenting results obtained from simulations of general radial deviatoric loading, a constant deviatoric strain test and a multi-axial plane strain test.