Free Surface Flow and Fracture in Granular Media

Granular media, like sand and powders, are very complex in their dynamics. Due to it there is not yet a set of equations valid over a wide range of several motion regimes. In this work we present a simple and unified analytical approach which takes into account the Coulomb's yield criterion (CYC) for the description of the free surface deformation in non cohesive granular media and the rupture patterns in cohesive granular media. Through the discussion of some examples and its comparison with experiments we show the usefulness and necessity of this criterion in this kind of problems.