Effects of segregation in binary granular mixture avalanches down inclined chutes impinging on defending structures

This study investigates the segregation processes and impact response of binary granular mixtures with identical densities but different sizes particles subjected to gravity. Deposition was compared using discrete element method (DEM) numerical experiment and laboratory experiment to determine the material parameters in the particle flow code in three dimensions (PFC3D). With proper material parameters, many numerical experiments were performed on an idealized binary granular mixture avalanche to reveal its kinetic properties, with a particular focus on the results of the final run-out distance, fluid velocity, and impact force exerted on defending structures. The simulation results show that the energy dissipation in granular avalanches is higher with uniform particle sizes than with mixed particle sizes, indicating lesser energy dissipation in segregation processes. Coarse particles also play an important role in determining the kinetic properties of binary granular mixture avalanches; specifically, they obviously affect the maximum impact force when the storage area length is small. On the other hand, fine particles play an important role when the storage area length is large. These results suggest that the effects of coarse particles in granular avalanches containing more than one particle size may be at least as important.