Exploring the relationship between particle shape and critical state parameters for granular materials using DEM

This paper establishes the relationship between particle shape and critical state parameters for granular materials using discrete element method (DEM). A series of DEM simulations are performed under drained triaxial test conditions considering a varying elongation parameter (η). The elongated particles are generated using a commonly employed multi-sphere approach. From the analysis of results, it is found that the macroscopic response of elongated particles exhibits post-peak strain-softening behaviour while reaching a critical state at an axial strain of ~ 40%. The critical state strength of granular materials is found to be dependent on η. The microscopic behaviour in terms of coordination number (CN) shows an exponential decay against axial strain. In the early stage, CN decreases with increasing η, while the steady-state CN is found to increase with an increase in η values. Furthermore, quantitative relationships are established among the shape parameters and critical state parameters, thus providing a way to develop macro-scale constitutive models with intrinsic micro-scale built-in properties of granular materials.