On the collision problem of simulant debris flow particles against concrete barriers of various strengths

This study investigates the collision mechanisms within particle-block systems, which are crucial for enhancing barrier designs intended to safeguard infrastructure from the impacts of debris flows. The study used Leighton Buzzard sand (LBS) grains and smooth glass beads (SGB) as simulants for debris flow particles to carry out impact tests, incorporating a novel laboratory technique that applies clay mineral coatings to simulate weathering effects on these particles. Additionally, comparative tests involving chrome steel balls (CSB) and rough glass beads (RGB) were conducted to evaluate the influence of particle properties on the collision behavior. The experiments focused on concrete barriers of varied strengths (the concrete grades include C25, C50, and C75), examining energy loss and the coefficient of restitution (COR). Findings indicated that energy dissipation occurred through the brittle to elastoplastic deformation of micro-asperities on SGB and LBS surfaces, with microparticle layers contributing to increased plastic energy loss in weathered grains. Notably, the redirection and rotation of irregularly shaped natural particles post-impact underscored significant mechanisms of energy redistribution. The concrete blocks with a lower compressive strength (C25) displayed greater surface plastic deformation, resulting in heightened energy dissipation and reduced COR. The study not only validated but also refined the impact force model in particle-block systems, proving its efficacy in predicting impact behaviors. These insights are crucial for understanding collision dynamics in particle-block systems.