We investigate the stress response function of a layer of grains, i.e. the
stress profile in response to a localized overload. The shape of the profile is
very sensitive to the packing arrangement, and is thus a good signature of the
preparation procedure of the layer. This study has been done by the use of
molecular dynamics numerical simulations. Here, for a given rain-like
preparation, we present the scaling properties of the response function, and in
particular the influence of the thickness of the layer, and the importance of
the location of the overload and measurement points (at the boundaries, in the
bulk).Comment: 6 pages, 4 figures, to appear in the proceedings of the "Traffic and
Granular Flow 2003" conferenc