Investigating the angle or response and maximum stability of a cohesive granular pile

Abstract

In this thesis, I investigate the static and dynamic properties of a granular heap made cohesive by an interstitial fluid. I present the results of experimental work measuring the maximum angle of stability and the angle of repose of such a pile in a rotating drum geometry. I discuss existing models for the stability of a cohesive granular pile and present a new model that predicts the maximum angle of stability from the pile's geometry and from the cohesive forces between grains. This model agrees well with experiment and suggests that friction is insignificant in determining the maximum angle of stability. In addition, I investigate the effect of the viscosity of the interstitial fluid on the dynamic properties of a granular pile. In particular, I examine the transition from stick-slip motion to continuous motion as well as the effect of viscosity on the angle of repose of the granular pile. I offer a qualitative explanation for my observations of these phenomena.