Seismo- and thermodynamics of granular solids

The recently published theory named Granular Solid Hydrodynamics (GSH) is outlined, supported and quantified with arguments from physics as well as soil mechanics. Seismodynamic equilibria serve to introduce a granular temperature T (g) and a related entropy s (g) , both with gradients. The evolution equations of GSH are first presented without gradients, parameters are proposed as functions of T (g) and estimated. Constant stretching leads to nearly hypoplastic relations for a certain range of T (g) . Cyclic deformations lead to pulsating T (g) and to asymptotic cycles of stress and density. State cycles are also attained with additionally imposed isochoric deformations (ratcheting). Similar attractors can be obtained with elastoplastic or hypoplastic relations with hidden variables. GSH is then presented with gradients and boundary conditions. Consequences for stabilization and destabilization are outlined by means of the total energy and with driven attractors. Conclusions and an outlook indicate that GSH is going to become a powerful unified concept.