Discrete Element Method Analysis on Shear Responses of Mixed Soil During Anisotropic Consolidation
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摘要: 为探明初始应力比影响不同细颗粒含量密实混合土的宏观剪切行为的细观机制,采用离散元法研究混合土的宏细观剪切行为。混合土由球形细颗粒和真实角砾形状粗颗粒组成。结果表明:初始应力比增大可以使混合土的初始加载阶段内摩擦角和剪胀角增大。通过分析粗颗粒–粗颗粒、粗颗粒–细颗粒、细颗粒–细颗粒接触的贡献大小,发现初始应力比对混合土的工程分类基本无影响。混合土的初始加载阶段,剪切强度随着初始应力比的增大而增大,与颗粒间接触力增大密切相关。在混合土的初始加载阶段,随着初始应力比的增大,内摩擦角的增大可归因于接触、法向接触力、法向和切向枝向量的各向异性增大程度之和超过了切向接触力的各向异性的减小程度。Abstract: 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.
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