Particle-scale origins of shear strength in granular media

Abstract

The shear strength of cohesionless granular materials is generally attributed to the compactness or anisotropy of their microstructure. An open issue is how such compact or anisotropic microstructures, and thus the shear strength, depend on the particle properties. We first recall the role of fabric and force anisotropies with respect to the critical-state shear stress. Then, a model of accessible geometrical states in terms of particle connectivity and contact anisotropy is presented. This model incorporates in a simple way the fact that, due to steric exclusions, the highest levels of connectivity and anisotropy cannot be reached simultaneously, a property that affects seriously the shear strength. We also analyze the force anisotropy in the light of the specific role of weak forces in sustaining strong force chains and thus the main mechanism that underlies anisotropic force patterns. Finally, we briefly discuss the effect of interparticle friction, particle shape, size polydispersity and adhesion.

References in corpus (6)

• Quasistatic rheology, force transmission and fabric properties of a packing of irregular polyhedral particles
• Force transmission in a packing of pentagonal particles
• Pre-avalanche instabilities in a granular pile
• Friction vs Texture at the Approach of a Granular Avalanche
• Multiscale Analysis of the Stress State in a Granular Slope in Transition to Failure
• Granular contact force density of states and entropy in a modified Edwards ensemble