Dry granular column collapse by elastic-viscoplastic constitutive model of dense granular flow

Dry granular column collapse is a significant and fundamental problem in the study of granular flow. Despite its apparent simplicity, accurately describing and predicting the collapse process remains challenging from a numerical perspective. In this study, we conducted a series of simulations to investigate the dynamic process of dry granular column collapse using the material point method with an elastic-viscoplastic constitutive model. The proposed constitutive model effectively captures the complex behavior of granular media, including the solid-like and fluid-like motion states under different stress states. The simulation results successfully reproduced the progressive transition from the relatively slow avalanches of shallow columns to the violent cascading collapses of tall columns. We further analyzed the influence of the initial aspect ratio on the final deposit configuration, as well as the internal friction effect in the elastic-viscoplastic model on the collapse dynamics. Power-law relationships for the runout distance and final height were obtained based on the numerical results, and the effects of the internal friction angle and static friction coefficient were investigated to assess their impact on the collapse process. Overall, the proposed numerical framework can greatly capture the collapse dynamics, providing an effective method for the simulation of granular flow.