Debris flows are rapid gravity-driven unsteady flows of highly concentrated mixtures of water and solid particle material, destroying numerous mountain building structures and traffic facilities. The investigation of debris flows is thus of significance to hazard prevention and mitigation. This paper aims to provide a numerical model capable of reproducing debris flow impact estimation by accounting for the complicated fluid-particle-structure interaction (FPSI) using a coupled smoothed particles hydrodynamics (SPH), discrete element method (DEM), and finite element method (FEM) approach. The fluid phase is represented by SPH. The solid phase consists of physical particle(s) and is represented by the DEM, and the deformable structure is represented by the FEM. The interaction forces among the fluid, solid particles, and structure are computed using the penalty function method. The proposed model is capable of simultaneously simulating a fluid-particle interaction (FPI), particle-structure interaction (PSI), and fluid-structure interaction (FSI), with good agreement between the complicated hybrid numerical and experimental results. Finally, a Wenjia gully debris flow is carried out to demonstrate the capability of the coupled model in simulating the FPSI as an application of debris flow impact simulations. When compared with the actual situation, the propagation of the debris flow and destruction of the structures were predicted accurately. Additionally, the Wenjia gully debris flow was treated, and the treatment measure was analyzed from the impact evolution (e.g., interception by dams, impact force, and destruction of dams). The developed method will contribute to a better understanding of the FPSI and is a promising tool for hazard analysis and mitigation.

泥石流是由重力驱动的，由水和固体颗粒物质组成的高度浓缩混合物的不稳定流动，它摧毁了许多山区建筑结构和交通设施。因此，对泥石流的调查对预防和减轻危害具有重要意义。本文旨在提供一种数值模型，该模型能够通过使用耦合的平滑粒子流体动力学（SPH），离散元方法（DEM）和有限元方法解决复杂的流体-粒子-结构相互作用（FPSI）来重现泥石流影响估算值（FEM）方法。流体相用SPH表示。固相由一个或多个物理粒子组成，由DEM表示，可变形结构由FEM表示。流体，固体颗粒之间的相互作用力 结构和结构是使用惩罚函数法计算的。所提出的模型能够同时模拟流固耦合（FPI），流固耦合（PSI）和流固耦合（FSI），并且在复杂的混合数值和实验结果之间具有良好的一致性。最后，文家沟泥石流进行了演示，证明了耦合模型在模拟FPSI中作为泥石流冲击模拟应用的能力。与实际情况相比，可以准确预测泥石流的传播和结构的破坏。此外，对文家沟泥石流进行了处理，并从冲击演化（例如，水坝截留，冲击力和水坝破坏）分析了处理措施。