Material characteristic-controlled particle segregation in rock-ice avalanche

Abstract

Rock-ice avalanches exhibit significant particle segregation driven by density and friction differences between ice and rock. This study meticulously uncovers intricate segregation dynamics in rock-ice avalanches, focusing on density variations, friction disparities, and ice volume fractions through physical flume experiments and numerical simulations. Results reveal clear patterns: ice particles cluster at front regions in flow, while rocks move to the rear. Ice occupies upper flow-depth areas, while rocks settle lower. In density-controlled segregation, low-density ice segregates upward and forward due to diminished inertia, whereas in friction-controlled scenarios, low-friction ice displays heightened flowability, causing forward and downward segregation. Density-controlled and friction-controlled segregation both result in forward segregation in the flow direction, exhibiting competitive dynamics in flow-depth. Lower ice volume fractions increase the relative slip of ice particles along shear planes, and decrease the relative slip of high-density rock particles in the flow-depth direction, accentuating forward segregation and reducing it in flow-depth.