Numerical Simulation of Granular Flows in a Large Flume Using Discontinuous Deformation Analysis

Excerpt

A long run-out rock avalanche is defined as an extremely rapid, massive, flow-like motion of fragmented rock derived from a bed-rock failure (Hungr et al. 2001). Due to their extraordinary mobility, rock avalanches have been extremely costly in terms of human lives and of engineering developments, and have interested many researchers. Numerical method appears a promising approach for analyzing most of the physical aspects of dry rock avalanches and for predicting the consequence of real events as well (Cundall and Strack 1979; Gonzales et al. 2002; Tommasi et al. 2008). The distinct element method (DEM) and discontinuous deformation analysis (DDA) are the two most popular discrete element methods used to tackle problems dealing with discontinuous rock mass. Limitations of the explicit DEM include its very small step for numerical stability and the use of artificial damping to absorb the energy generated from the relaxation analysis to maintain equilibrium, although some researchers (Calvetti et al. 2000; Valentino et al. 2008) have devoted to appropriately calibrate numerical damping in simulating run-out of granular flows. Shi (1988) claimed that the energy-based DDA can overcome the two limitations of the force-based DEM. Based on its advantages, this paper selected DDA as the analysis method to investigate the behavior of granular flows. …