Stability of a granular layer on an inclined "fakir plane"
  We present here experimental results on the effect of a forest of cylinder obstacles (nails) on the stability of a granular layer over a rough incline, in a so-called "fakir plane" configuration. The nail forest is found to increase the stability of the layer, the more for the densest array, and such an effect is recovered by a simple model taking into account the additional friction force exerted by the pillar forest onto the granular layer. 
Jesica Benito, Yann Bertho, Irene Ippolito, Philippe Gondret
cond-mat.soft physics.geo-ph