Dynamics of bouldery debris flow impacting onto rigid barrier by a coupled SPH-DEM-FEM method

Abstract

Boulders entrained in debris flows can often generate destructive impact forces and cause damages to rigid barriers. In this study, a large-scale numerical flume model based on the smoothed particle hydrodynamics (SPH), the discrete element method (DEM) and the finite element method (FEM) is established to investigate the impact of bouldery debris flow onto a rigid barrier. The numerical model is first validated with the reported experimental data, in terms of the impact force, the displacement of boulder and flow front. The numerical model is then used to investigate the dynamic interaction between bouldery debris flow and rigid barrier, the energy dissipation of the boulder and the mechanism of buffering effect of debris flow. The numerical results show that the debris slurry can provide a buffering effect to the boulder by reducing the boulder kinetic energy. The buffering effect decreases with the channel slope. Based on the numerical results, a load reduction factor is recommended to consider the buffering effect. The findings of this study can provide some references for the design of rigid barrier.