Granular column collapse: Analysis of inter-particle friction effects

The purpose of this paper is to investigate the effects of inter-particle friction on the granular column collapses via the discrete element method (DEM) while eliminating the particle-size effects. As the inter-particle friction increases, the runout distance decreases, the deposit height increases, the force chains tend to be closer to the vertical upward direction, the percentage of the strong force chains become greater and the granular assembly is less susceptible to the external gravity field, thus making the collapse tend to be toppling-dominant flow. The correlation between the initial height and runout distance of particles at the final deposits becomes stronger when the collapse tends to be more toppling-dominant. The motion patterns of the collapse are governed by the inter-particle friction and initial aspect ratio through dimensional analysis and the effective aspect ratio parameter is proposed to classify granular column collapse into three regimes (sliding-dominant, transition, and toppling-dominant collapse).