Load Deflection Of Flexible Ring Net Barrier In Resisting Debris Flows

Abstract

Quantitative understanding of the load deflection mechanisms of a flexible barrier in intercepting debris flows is critical for barrier design, but remains practically challenging due to difficulties involved in capturing multi-phase, multi-way interactions. This study employs a physics-based coupled computational fluid dynamics and discrete element method (CFD-DEM) to simulate a flexible ring net barrier as a permeable, deformable multi-component system by DEM and model a debris flow as a mixture of discrete particles and a continuous slurry by DEM and CFD, respectively. The CFD-DEM coupling framework offers a unified treatment of in-flow solid-fluid interaction, flow-barrier interaction, and interactions among barrier components. Numerical predictions of key flow-barrier interactions and cable forces show reasonable consistency with large-scale experiments. Systematic simulations with varying flow-barrier height ratios ε and flow dynamics are performed to examine the evolving mechanisms of load sharing and transmission and quantify the ε-dependent load-deflection modes. The ratio ε is found to bear a strong, positive correlation with key barrier response in three typical modes. The post-peak barrier deformations experience shrinkages with ε≤0.6 and expansions when ε>0.6. This study helps to improve the understanding of the load-deflection mechanisms for practical design of flexible barriers in mitigating debris flows.