Creep and fluidity of a real granular packing near jamming

van Bau Nguyen (1, 2) , Thierry Darnige (2) , Ary Bruand (1) , Eric Clément (2)

1 ISTO - Institut des Sciences de la Terre d'Orléans
2 PMMH - Physique et mécanique des milieux hétérogenes (UMR 7636)

We study the internal dynamical processes taking place in a granular packing below yield stress. At all packing fractions and down to vanishingly low applied shear, a logarithmic creep is observed. The experiments are analyzed using a viscoelastic model which introduces an internal, time-dependent, fluidity variable. For all experiments, the creep dynamics can be rescaled onto a unique curve which displays jamming at the random-close-packing limit. At each packing fraction, we measure a stress corresponding to the onset of internal granular reorganization and a slowing down of the creep dynamics before the final yield.

Domaines: Interfaces continentales, environnement; Milieux et Changements globaux

van Bau Nguyen, Thierry Darnige, Ary Bruand, Eric Clément. Creep and fluidity of a real granular packing near jamming. Physical Review Letters, 2011, 107, 5 p. ⟨10.1103/PhysRevLett.107.138303⟩. ⟨insu-00626361⟩