Comparison of SPH boundary approaches in simulating frictional soil–structure interaction

Two boundary algorithms in the framework of 3D smoothed particle hydrodynamics (SPH) method are proposed. The algorithms are capable of accounting for the friction and energy dissipation at elastic–plastic contacts between SPH particles and a solid boundary. Utilizing the proposed boundary algorithms, the accuracy of different methods to calculate the interaction force between SPH particles and a boundary surface is investigated. The effect of SPH artificial viscosity on the oscillation and accuracy of the calculated interaction force is also examined. It is found that using high artificial viscosities may unphysically damp out energy of the system and the use of dynamic artificial viscosity, which varies with time and space, may remediate this problem. Employing the proposed frictional boundary algorithms, the effect of basal friction on the collapse of granular columns is investigated. It is shown that the flow of a collapsing granular column can be divided into three flow regimes: a conical-shaped stationary regime, a collapsing regime, and a spreading regime. It is found that the existence and the interaction of these regimes are affected by basal friction. Additionally, the effect of basal friction on the final runout distance and deposit height is investigated.