On the impact of dry granular flow against a rigid barrier with basal clearance via discrete element method

Rigid barriers are prevalent structure countermeasures for mitigating granular flow hazards in mountainous areas. To reduce maintenance for barriers, a basal clearance is commonly set between the base of the barrier and the channel base. A rational design of the clearance is still an important and open issue. In this study, the interactions between a dry granular flow and rigid barriers with different basal clearances are investigated through discrete element modeling of flume tests. The numerical model is firstly validated by comparing the numerical results with the experimental data reported in the literature. This model is further employed to evaluate the influence of basal clearance and slope angle on the flow–barrier interactions. The ratio between the clearance size and particle diameter is varied from 0 to 4, and the slope angle is varied from 15 to 40°. Based on the numerical results, the value of the clearance size that causes clogging of the clearance is identified. The influences of basal clearance and slope angle on the outflow rate, energy-breaking efficiency, and retention efficiency are quantified. The obtained results can provide some insights into the design of basal clearance for a rigid barrier.