Micro-mechanics of contact erosion

In the present paper a simulation framework is presented coupling the mechanics of fluids and solids to study the contact erosion phenomenon. The fluid is represented by the Lattice Boltzmann Method (LBM) and the soil particles are modeled using the Discrete Element Method (DEM). The coupling law considers accurately the momentum transfer between both phases. A soil composed of particles of two distinct sizes is simulated by the DEM and then hydraulically loaded with an LBM fluid. It is observed how the hydraulic gradient compromises the stability of the soil by pushing the smaller particles into the voids between the largest ones. The hydraulic gradient is more pronounced in the areas occupied by the smallest particles due to a reduced constriction size, which at the same time increases the buoyancy acting on them. At the mixing zone, where both particles sizes coexist, the fluid transfers its momentum to the small particles, increasing the erosion rate in the process. The results offer new insights into the erosion and suffusion processes, which could be used to better predict and design structures on hydraulically loaded soils