Dilatancy of frictional granular materials under oscillatory shear with constant pressure

TL;DR

This study uses numerical simulations to explore how frictional granular materials expand or compact under oscillatory shear at constant pressure, revealing dilatancy and pressure-dependent compaction behaviors.

Contribution

It demonstrates the conditions under which dilatancy and compaction occur in frictional granular systems subjected to oscillatory shear.

Findings

Dilatancy occurs with increasing strain amplitude.

Compaction occurs at intermediate strains for low friction.

Dilatancy is largely unaffected by pressure, unlike compaction.

Abstract

We perform numerical simulations of a two-dimensional frictional granular system under oscillatory shear confined by constant pressure. We found that the system undergoes dilatancy as the strain increases. We confirmed that compaction also takes place at an intermediate strain amplitude for a small mutual friction coefficient between particles. We also found that compaction depends on the confinement pressure while dilatancy little depends on the pressure.