DEM simulation of cohesive soil-pushing behavior by bulldozer blade

摘要

A numerical simulation based on discrete element method (DEM) is performed for excavation and pushing process of soil by a bulldozer blade. Soils contain water and a resistance working on a blade is largely influenced by the cohesive force due to liquid-bridges formed in-between soil particles. In the present study, a cohesive bond force model proposed by Utili & Nova (2008) is introduced in which the microscopic behavior of cohesive force is modeled as it matches with macroscopic shear destruction characteristics. A tetra-particle model is also introduced to incorporate the effect of non-sphericity of soil particles. The magnitude of microscopic cohesive force and friction angle between particles are varied and its dependency is verified. Present results are still qualitative, however, characteristic soil behaviors during excavation and pushing processes such as " piling-collapsing" phenomena are observed by choosing an appropriate set of model parameters. For the quantitative predictions in near future, we also have discussions for model parameters.