Smooth particle hydrodynamics and discrete element method coupling scheme for the simulation of debris flows

Debris flows have been widely researched during the last decades since they are catastrophic events with significant infrastructure and environmental impacts. Typically, they are composed of various materials which interactions are worth for studying, to improve the prediction of some variables, such as velocities, forces and affected areas. Constitutive models and numerical methods are fundamental in broadening the knowledge of the behaviour of these phenomena. Thus, the coupling of numerical techniques, for the different constituents of debris flow is becoming indispensable to describe the behaviour of these natural events. The coupling of Smooth Particle Hydrodynamics (SPH) and Discrete Element Method (DEM) is presented in this paper to show the capacity to represent the interaction of several materials at the same time. SPH is employed to represent the fluid and soil by using different constitutive models from a continuum approach. In contrast, DEM is used to represent immersed objects such as boulders and boundary conditions. In this sense, we can couple the behaviour that occurs at very different scales in a unified framework more suitable to describe the heterogeneity of debris flows. Benchmark cases were solved to validate this new approach. The simulations show good agreement with analytical solutions, experimental results and field data.