SPH modeling of soil structure interactions using a novel non-local contact method

Smoothed Particle Hydrodynamics (SPH) is popular for modeling the interactions between soils and structures, in which the contact mechanism is crucial. The traditional contact methods apply the interplay forces between the outermost layers of different bodies represented by Lagrangian particles within SPH, referred to as local strategy in this study. However, such a strategy has been shown to induce particle disorders along the interface and potential computational errors, resulting from the momentum imbalance of the remaining particles located in the influence domain of the interface due to the well-known particle deficiency. With this regard, a non-local contact method (NLCM) is proposed to regulate the shortcomings of the traditional contact methods by assigning all SPH particles influenced by the boundary with reasonable interaction forces based on theoretical derivation. Besides, the hypoplastic model incorporating the critical state is employed to describe the granular soil’s behavior. To validate the novel method, four benchmark problems are simulated. Good consistency is found between the results from numerical simulations and theoretical solutions or experimental observations, including static sand column, sand column collapse, plane strain compression test, and buried pipe uplift. Finally, the proposed SPH model is applied to investigate the earth pressure distribution and failure mechanism of retaining walls. The significant effects of two factors, soil compactness and soil-wall friction angle, on the distribution of slip surfaces and earth pressures during active and passive failure are revealed.