Smoothed particle hydrodynamics simulations of dynamic and quasi-static axisymmetric collapse of granular columns

Granular materials may exhibit solid- to fluid-like behaviors under different flow conditions. This makes granular flow an interesting topic for research, which has gained significant attention in the recent years. In particular, the collapse of granular columns within dynamic/rapid and slow/quasi-static flow regimes has been the subject of various experimental and numerical studies and provided invaluable insights into phenomena such as landslides, avalanches, active movement of retaining walls, etc. In this study, the axisymmetric collapse of granular columns has been numerically investigated using three-dimensional (3D) smoothed particle hydrodynamics (SPH) models. The elastoplastic behavior of granular materials is modeled through using Drucker-Prager constitutive model with non-associated flow rule. Quasi-static and dynamic collapses of granular columns with a wide range of initial aspect ratios are modeled using the developed model. The flow was triggered by removing or expanding the cylindrical wall for dynamic and quasi-static flow types, respectively. Results of simulations are validated against experimental data on dynamic collapse of granular columns. Moreover, the developed models provide the means for a comprehensive comparison between quasi-static and dynamic axisymmetric collapses of granular columns, in terms of collapse pattern, final deposit profile, and energy dissipation. The results reveal qualitative similarities between these types of collapses, emphasizing the importance of the initial aspect ratio of the column on deposit morphologies, collapse pattern, and energy dissipation.