Investigation of Debris Flow Impact Mechanisms and Designs

Abstract

AbstractDebris flows are catastrophic landslides increasing in severity in recent decades due to the more frequent and intense rainfall events under climate change. Debris flows pose a serious threat to infrastructure, settlements, and the natural environment in mountainous regions around the world causing considerable economic losses every year. To mitigate debris flows, single and multiple rigid and flexible barriers are constructed along the predicted debris flow paths. Compared with single barriers, multiple barriers are more advantageous in mitigating large debris flow volumes by progressively retaining and decelerating the flow with much smaller barrier sizes. These smaller barriers are not only easier to construct on steep hillslopes but also reduce the carbon footprint compared to large single barriers. However, current understanding of debris flow impact mechanisms on single and multiple barriers is limited due to the complex composition and scale-dependent nature of debris flow. The need of using different barrier configurations further adds to this complexity and the impact mechanisms of debris flow against single and multiple barriers are yet to be elucidated, thereby hindering the development of scientific design guidelines. This paper examines the impact mechanisms of water, dry granular and two-phase debris flows on barriers of varying stiffness, openings and numbers based on physical and numerical results, and provides recommendations for design of debris-resisting single and multiple barriers.