Dynamic Failure of Granular Slopes: Due to Unidirectional Stress Transfer or Multi-dimensional Wave Propagation?

Abstract

In order to numerically study fracture development in solids, models composed of discrete elements are often assumed instead of those based on continuum mechanics. Although realistic results have been obtained through the investigation of discontinua, the real fracture process in discrete media, in particular that under dynamic loading conditions, has not been experimentally scrutinized thoroughly. Here, we employ experimental technique of dynamic photoelasticity in conjunction with high speed cinematography and trace evolution of fracture inside discontinuous media. Especially, we consider dynamics of two-dimensional dry granular slopes consisting of penny-shaped birefringent elastic particles and having some inclination angle. The observations of transient stress and fracture development owing to dynamic impact on the top slope surface indicate that at least two specific failure patterns exist and whichever occurs seems to be governed by force-chain-like unidirectional stress transfer and continua-like multi-dimensional wave propagation.