Discrete Element Method Analysis on Shear Responses of Mixed Soil During Anisotropic Consolidation

To explore the microscopic mechanisms of the macroscopic shear responses of dense-mixed soil with different contents of fine particles affected by initial stress ratios, the discrete element method was used to study the macroscopic and microscopic shear responses of mixed soil. Mixed soil consisted of spherical fine particles and coarse particles with real gravel shapes. Research indicated that an increase in initial stress ratios could increase both friction and dilatancy angles at initial loading stages. It was found that initial stress ratios had little influence on engineering classifications of mixed soil by analyzing the contact contributions of coarse-coarse, coarse-fine, and fine-fine particles. With increase in initial stress ratios, the shear strength of mixed soil increased at initial loading stages, which was closely related to an increase in contact forces particles. With increase in initial stress ratios, the increase in internal fiction angles at initial loading stages could be attributed to the anisotropic increase degree of contact, normal contact force, normal and tangential branch vectors beyond the anisotropic decrease degree of tangential contact force.