LOCAL SLIP PLANES IN ACCELERATED GRANULAR MEDIA

We study analytically the local slip planes in non cohesive granular m edia within a box subjected to uniform rectilinear acceleration. By us ing the phenomenological Coulomb's method of wedges we found that the angles of the slip planes and the resulting average forces at the wall are strongly changed as a function of the acceleration's magnitude of the system, even if it is so small such that the shape of the free su rface is maintained unchanged.