Effects of Barrier Stiffness on Debris Flow Dynamic Impact—I: Laboratory Flume Test

Abstract

Debris flows often cause local damage to engineering structures by exerting destructive impact forces. The debris-flow–deformable-barrier interaction is a significant issue in engineering design. In this study, a large physical flume model test device was independently designed to repeatedly reproduce the flow and impact process of debris flow. Three physical flume tests were performed to investigate the effect of barrier stiffness on the debris flow impact. The flow kinematics of debris flow with three barrier stiffness values are essentially consistent with the process of impact–run-up–falling–pile-up. The development of a dead zone provided a cushion to diminish the impact of the follow-up debris flow on the barrier. The peak impact forces were attenuated as the barrier stiffness decreased. The slight deflections of a deformable barrier were sufficiently effective for peak load attenuation by up to 30%. It showed that the decrease of the barrier stiffness had a buffer effect on the debris flow impact and attenuated the peak impact force. And with the decrease of the barrier stiffness, when the barrier was impacted by the same soil types, the recoverable elastic strain will be larger, and the strain peak will be more obvious.