Investigation of the protective effect of baffles against soil-rock mixture disasters using the MPM-DEM method

This paper proposes a coupled Material Point Method and Discrete Element Method (MPM-DEM), where particle-particle and particle-plane contact models are formulated in a unified framework to model soil-rock-structure interactions. In this method, soil's behavior is modeled using MPM, rock's motion is modeled using DEM, while soil-rock and rock-rock interactions are represented by the particle-particle contact model. Soil-structure and rock-structure interactions are captured through the particle-plane contact model. This method allows for realistic modeling of the dynamic process involved in soil-rock mixture disasters, such as debris flows, and enables accurate calculation of contact forces between them and structures. The protective effect of baffles against granular flows with different rock contents and rock sizes is investigated through a flume test. Key indicators, including kinetic energy, blocked volume, and impact force, are analyzed, revealing that these factors are significantly influenced by both rock content and rock size. The findings can provide a reliable reference for the design of disaster protection structures for soil-rock mixture disasters in practical engineering.