Simulation on the Process of Contact Erosion between Cohesionless Soils

Abstract

To explore the mechanism of contact erosion, cohesionless soil layers subjected to a flow parallel to the interface were simulated using particle flow code (PFC). The calculation model with different particle size ratio D15/d85 from 1.84 to 6.88 between two soil layers was designed based on the experiment. The movement process of the particles during contact erosion was explored. The results show that, when one particle was eroded, it first moved up into bigger pores and then was carried out along the flow direction. A grain size transition zone gradually formed between two layers, where particles of two soil layers mixed. For numerical samples with particle size ratio D15/d85 larger than 4.0, the eroded particles could all be carried out by the flow, so the particle size ratio D15/d85 at the transition zone remained larger than 4.0 according to Terzaghi’s particle retention criterion; thus, the erosion continued resulting in the increase in the flow velocity and the erosion rate.