Geometrical frustration: a dynamical motor for dry granular media

We propose a two-dimensional geometrical model that takes into account geometrical effects of frustration in the rearrangement processes in granular systems. In particular we related the microscopic motor of compaction to the need of cooperative rearrangements in order to find a better packing. In this framework it is possible to reproduce the experimental results for the compaction behavior. Moreover the system with different degrees of frustration shows segregation phenomena.