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为了研究颗粒级配对粒状材料不排水力学特性的影响,采用两种形状自相似度很高的材料(玻璃球和Hostun砂)进行了一系列传统三轴不排水压缩试验。对于每种材料,保持相近的相对密实度制作了6个不同颗粒级配(不均匀系数Cu=1.1~20)的试样,然后进行剪切。试验结果表明,颗粒级配对粒状材料的不排水力学性能存在明显影响:两种材料试样的偏应力水平随着不均匀系数的增加而降低,抗剪强度随着材料的不均匀系数Cu的增加而降低,并在Cu=5后呈现出趋稳势态。基于不排水剪切试验中颗粒集合体二阶功的演化规律,对材料受荷载过程中出现不稳定性的条件进行分析。结果表明,在相同密实度下,粒状材料的静态液化潜能随着材料不均匀系数Cu的提高而增强,高不均匀系数的材料变得不稳定。
In order to study the effect of particle size distribution on the mechanical properties of undrained granular materials, a series of conventional triaxial undrained compression tests were carried out on two highly self-similar materials (glass balls and Hostun sand). Six specimens of different grain sizes (with a non-uniform coefficient of Cu = 1.1 to 20) were produced with similar relative densities for each material and then sheared. The experimental results show that the particle size distribution has a significant effect on the undrained mechanical properties of granular materials: the deviatoric stress of the two materials samples decreases with the increase of the non-uniform coefficient, and the shear strength increases with the increase of the non-uniform coefficient Cu But decreased and showed a steady state after Cu = 5. Based on the evolution of the second-order work of particle aggregates in undrained shear tests, the material instability condition during loading was analyzed. The results show that under the same density, the static liquefaction potential of granular materials increases with the increase of material nonuniformity Cu, and the material with high heterogeneity becomes unstable.