Dynamic Response of Granular Flows on a Rigid Barrier: Dense versus Dilute Flow

Devastating natural hazards induced by the propagation of extremely rapid, flow-like fragmented rocks can be reduced or even avoided by protective structures in the corresponding danger areas. Such barriers are expected to store the mass before it threatens the vulnerable infrastructures. Proper designs are required by calculating the peak impact force of granular flows on the barriers. In this work, a discrete element method (DEM) was validated with a physical experiment. Sixty simulations were carried out using DEM to study the flow regime governing the dynamic response of granular flows against the barrier. Results reveal that the inertial number (I) can demarcate the flow regime into dense and dilute flow. For the dense flows (I < 3), the equation based on the hydrodynamic model is much more efficient. For the dilute flows (I > 3), the Hertz contact method is better at calculating the peak load. The aforementioned findings are expected to be convenient for engineers designing mitigation constructions against flow-like hazards in mountain areas.