Collapse dynamics and deposition morphology of granular soils avalanching from inclined to horizontal planes

Granular column collapses exhibit rich dynamics, and are often observed in landslides, sediment transports, pyroclastic flows, and other planetary surface processes, as well as in many industrial situations. This work utilizes the classical discrete element method (DEM) to investigate the scaling behavior and deposition morphology of granular avalanches, whose initial packing sits originally on an inclined plane, but collapses eventually onto a horizontal plane. By varying the width of non-periodic lateral boundaries, setting up periodic boundary conditions, and tuning both the inclination angle and the interparticle frictional coefficient, we are able to elucidate the influence of boundaries and establish a clear analogy with classical granular column collapses over horizontal planes. With the assistance of previously obtained finite-size scaling of granular column collapses, we find that the simulation setups in this work can also be described by a finite-size scaling solution with carefully tuned parameters and a characteristic inclination angle, θc. In particular, we observe a clear transition from layered flow to bulk sliding with the increasing inclination angles. This work provides quantitative solutions to describe the scaling of runout distances, collapse durations, and maximum front velocities, and can be further extended to other scenarios with different topographical features, and to help shed light on the runout dynamics and hazardous results of related natural geophysical systems.