Pre-avalanche instabilities in a granular pile

Lydie Staron (1) , Jean-Pierre Vilotte (1) , Farhang Radjai (2)

1 IPGP - Institut de Physique du Globe de Paris
2 PMMG - Physique et Mécanique des Milieux Granulaires

We investigate numerically the transition between static equilibrium and dynamic surface flow of a 2D cohesionless granular system driven by a continuous gravity loading. This transition is characterized by intermittent local dynamic rearrangements and can be described by an order parameter defined as the density of critical contacts, e.g. contacts where the friction is fully mobilized. Analysis of the spatial correlations of critical contacts shows the occurence of ``fluidized'' clusters which exhibit a power-law divergence in size at the approach of the stability limit. The results are compatible with recent models that describe the granular system during the static/dynamic transition as a multi-phase system.

Domaines: Autre [cond-mat.other]

Lydie Staron, Jean-Pierre Vilotte, Farhang Radjai. Pre-avalanche instabilities in a granular pile. Physical Review Letters, 2002, 89, pp.204302. ⟨10.1103/PhysRevLett.89.204302⟩. ⟨hal-00120707⟩