The slumping of a cohesive granular column: Continuum and discrete modeling

Abstract

Cohesion forces strongly alter the flow properties of a granular material. To investigate this influence, we focus on a simple configuration: the collapse of a cohesive granular column. To do so, we adopt a numerical approach and implement a peculiar rheology in a Navier–Stokes solver (Basilisk): the so-called μ(I)-rheology, usually used for dry granular materials, supplemented by a yield stress for cohesion. With this approach, we recover the stability of the column, assuming the classical Mohr–Coulomb criterion for failure. We then compare this approach with a code based on contact dynamics, which implies forces at the grain scale: we recover the stability of the column as well. Furthermore, this comparison enables us to estimate the macroscopic yield stress based on the cohesive contacts between grains, which bridges the gap between continuous and discrete approaches of cohesive granular matter.