Rheology of rock–ice avalanche in a periodic chute flow

Rock–ice avalanches in frigid high-altitude regions exhibit exceptional mobility and significant destructive potential, yet the rheological mechanisms governing these dynamics remain poorly understood. This study employs discrete element method simulations to systematically investigate the steady-state rheological parameters of such avalanches. We examine both monocomponent systems and binary particle mixtures, establishing equilibrium flow configurations through controlled variations of inclination angles, initial heights, and ice content. Depth-resolved profiles of six key parameters—velocity, solid volume fraction, shear stress, normal stress, shear rate, and inertia number—were recorded during steady flow conditions. The results demonstrate height-dependent fluctuations in rheological characteristics influenced by local compositional variations and bulk density stratification. While the existing rheological model accurately describes monocomponent systems, we propose a modified formulation for binary mixtures that predicts both homogeneous mixing and segregation patterns. Crucially, this extended model retains the original parameter set calibrated from monocomponent data while successfully forecasting the effective friction coefficients and solid volume fractions observed in mixed systems. The computational predictions show strong agreement with simulation results, particularly in capturing the density-driven stratification comprising ice-enriched surface layers, mixed intermediate zones, and gravel-dominated basal regions.