Where does a cohesive granular heap break?

TL;DR

This paper investigates how cohesion influences the stability and failure location of granular heaps, highlighting the importance of load-dependent cohesive forces in failure localization.

Contribution

It provides a detailed analysis of how cohesion and its dependence on normal load affect the maximum stability angle and failure plane localization in granular heaps.

Findings

Failure occurs deep inside the heap with constant cohesion.

Surface failure occurs when cohesion depends linearly on normal stress.

Dependence of cohesion on normal load is crucial for failure localization.

Abstract

In this paper, we consider the effect of cohesion on the stability of a granular heap. We first briefly review literature results on the cohesion force between two rough granular beads and specifically consider the dependence of the adhesion force on the normal load. We then compute the dependence of the maximum angle of stability of the heap as a function of the cohesion. We point out that the dependence of the cohesive forces on the external normal load between grains is a key point in determining the localization of the failure plane. While for a constant cohesive force, slip occurs deep inside the heap, surface failure is obtained for a linear dependence of the cohesion on the normal stress.