Unified Mechanical Erosion Model for Multi-phase Mass Flows

Abstract

Erosion poses a great challenge in multi-phase mass flows as it drastically changes flow behavior and deposition pattern by dramatically increasing their masses, adversely affecting population and civil structures. There exists no mechanically-explained, unified multi-phase erosion model. We constitute a novel, unified and comprehensive mechanical erosion rates for solid and fluid phases and demonstrate their richness and urgency. This is achieved by seminally introducing interacting stresses across erosion-interface. Shear resistances from the bed against shear stresses from the landslide are based on consistent physical principles including frictional, collisional and viscous stresses. Proposed multi-phase interactive shear structures are mechanically superior and dynamically flexible. Total erosion rate is the sum of solid and fluid erosion rates which are mechanically extensive and compact. Erosion rates consistently take solid and fluid fractions from the bed and customarily supply to solid and fluid components in the flow. This overcomes severe limitations inherited by existing models. For the first time, we physically correctly construct composite, intricate erosion velocities of particle and fluid from the bed and architect the complete net momentum productions that include all interactions between solids and fluids in the landslide and bed. We invent stress correction, erosive-shear-velocity, super-erosion-drift and erosion-matrix characterizing erosion processes. By embedding well constrained extensive erosion velocities, unified erosion rates and net momentum productions including erosion-induced inertia into mass and momentum balances, we develop a novel, mechanically-explained, comprehensive multi-phase model for erosive mass flows. The new model offers great opportunities for practitioners in solving technical, engineering problems related to erosive multi-phase mass flows.