Modeling the Accumulated Damage in Rock Bed during Saltating Abrasion through Particle Flow Simulation

摘要

Sediment yield may play double roles on rock-bed abrasion; it provides either a tool effect to enhance abrasion or arncover effect to protect rock bed from abrasion. For exposed rock riverbed contains few discontinuities, saltatingrnabrasion can be a dominant mechanism controls the incision rate of riverbed. During flooding, the moving bed loadrncan cause saltating abrasion to take place due to particles’ impacts on the riverbed; particle impact results in localrnfailure and causes abrasion. Sklar(2004) proposed a mechanics-based approach, together with a few empiricalrnrelations, to model saltating abrasion of rock. Few existing erosion models have looked into the micromechanics ofrnrock erosion. This study made use of particle flow simulation to model the erosion process of soft rock in microscopicrnscale. In the simulation, a rock material is modeled as a granular assemblage with inter-particle bonding; the erosionrnprocess can be simulated as particles’ release due to the loss of bonding. The presented work correlates the rate ofrndissipated energy during saltation process to the erosion rate. We attempt to use the dissipate energy as a damagernindex to represent the degree of accumulated damage in rock material due to continuous particle impacts. The ultimaterngoal is to develop an energy-based model for rock erosion dominated by saltating abrasion mechanism.