Particle Morphological Effects on the Behaviour of Dry Granular Flow Against Rigid Obstacles

Abstract

Geohazards such as rockfall, catastrophic landslides, and debris flow pose a significant risk due to the rapid movement of the vast amount of granular material carrying tremendous destructive potential and energy. Experimental and numerical studies on channelized flumes have been prevalent in analyzing the kinematics and dynamics of the flow and their interaction with various mitigation measures along the projected flow path. Continuum, discontinuum, and hybrid numerical methods have been successfully employed in the past to comprehend the complex material behaviour of granular mass flows. Although the numerical schemes within a continuum setting offer some insights into critical factors like flow velocity, flow depth, runout distance, etc., the granular interaction within the particle ensemble and the impact force on the barrier system for a better estimate of the force-transmission paths cannot be accounted for. The present study employs the Discrete Element Method to investigate the underlying physics of the micromechanical interaction of the granular assembly with the rigid barrier. Although past studies have explored granular flow-like events within a discrete setting, such studies did not incorporate particle morphology. This paper explores the effect of particle shape on kinematics and impact dynamics against a rigid obstacle. First, the numerical results have been benchmarked against the experimental studies for conventional spherical particles, and then we explore the effect of particle morphology. The present findings indicate that the particle shape significantly influences the flow kinematics and leads to a reduction in impact force on the barrier due to the higher angularity of particles with different morphological features than spherical particles, generally considered in the existing literature. A more significant implication of this study is to better understand and design mitigation measures against geohazards.