ABSTRACT
Contrary to the firmly established mechanics of continuum media, the mechanical behavior of particles in granular media, especially that under dynamic load, has not been fully understood. Here, as an initial investigation into wave and fracture propagation inside granular media, experimental technique of dynamic photoelasticity is utilized. Penny-shaped birefringent particles are prepared and placed on a rigid horizontal plane and two-dimensional dry model slopes with some inclination are formed. Using a high-speed digital video camera, the transient stress and fracture development due to dynamic impact on the top free surface of the model slope is recorded. It is found that there exist at least two failure patterns depending on the energy profile associated with the impact: (i) total collapse of the slope or mass flow resulting from one-dimensional force-chain-like stress transfer; and (ii) dynamic, toppling failure-like separation of the slope face induced by widely spread multi-dimensional wave propagation.
