title: Transition from rolling to jamming in thin granular layers.
abstract: We study the granular jamming transition for sheared layers of spherical beads ranging in thickness from 1 to 3 times the grain diameter d. As the layer thickness increases slightly above d, the measured friction jumps discontinuously from 0.02 to >0.1, marking the transition from rolling to jamming. Above a critical layer thickness for jamming, the effective granular pressure displays a power law increase with thickness. For thin layers, friction and P increases as the packing fraction decreases near the jamming transition, in contrast to expectations for bulk granular matter.
authors.affiliation: Department of Geosciences and Energy Institute Center for Geomechanics, Geofluids, and Geohazards, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. cjm@geosc.psu.edu
authors.forename: C
authors.initials: C
authors.lastname: Marone
authors.forename: B M
authors.initials: BM
authors.lastname: Carpenter
authors.forename: P
authors.initials: P
authors.lastname: Schiffer