Force Correlations and Arch Formation in Granular Assemblies

In the context of a simple microscopic schematic scalar model we study the effects of spatial correlations in force transmission in granular assemblies. We show that the parameters of the normalized weight distribution function, P(v)~v^αexp(-v/φ), strongly depend on the spatial extensions, ξV, of such correlations. In particular, we evaluate the functions φ(ξV) and α(ξV). If ξV→∞ then φ~ξV and weights are power law distributed.