Pressure dependent friction on granular slopes close to avalanche

TL;DR

This study explores how pressure-dependent surface deformations influence the stability and sliding behavior of objects on inclined granular slopes near avalanche conditions, revealing a critical pressure for minimal friction.

Contribution

It introduces the role of surface deformations in granular slope stability and identifies a specific pressure where friction is minimized, with implications for movement on sandy slopes.

Findings

Heavy objects create stabilizing deformations.

Light objects remain stable without disturbing the surface.

Intermediate pressures lead to destabilization and sliding.

Abstract

We investigate the sliding of objects on an inclined granular surface close to the avalanche threshold. Our experiments show that the stability is driven by the surface deformations. Heavy objects generate footprint-like deformations which stabilize the objects on the slopes. Light objects do not disturb the sandy surfaces and are also stable. For intermediate weights, the deformations of the surface destabilize the objects and generate sliding. A characteristic pressure for which the solid friction is minimal is evidenced. Applications to the locomotion of devices and animals on sandy slopes as a function of their mass are proposed.