Liu Yiming, Liao Xinchao, Li Lihua, Mao Haijun
School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan 430068, China.
Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China.
Materials (Basel). 2020 Dec 15;13(24):5716. doi: 10.3390/ma13245716.
Sand-rubber mixtures (SRMs) consisting of stiff sand particles and soft rubber particles are typical binary mixture materials that possess a variety of complicated properties. The complexity of the properties of sand-rubber mixtures is increased when complex stress path is involved. This study investigates the mechanical behavior of sand-rubber mixtures under generalized loading conditions using the discrete element method. A series of numerical true triaxial shear tests were conducted on pure sand and sand-rubber mixtures. The effect of rubber content and loading path on both of the macroscopic and microscopic performances of sand-rubber mixtures was investigated, and the associated microscale mechanism was also discussed. Numerical simulations show that the relationship between the peak friction angle ϕp and the intermediate principal stress ratio b is influenced by the addition of rubber particles, and a suggested explanation of this phenomenon is that the rubber particles mainly affect the inherent stability of the strong network. Particle-scale observations, including the coordinate number, the proportion of strong contacts, and the fabric anisotropy, are also presented in this study. Microscopic results confirm the explanation above, and explore the force transmission characteristics of sand-rubber mixtures under generalized loading conditions. This research can provide a reference for the constitutive model development of sand-rubber mixtures.
由坚硬砂粒和柔软橡胶颗粒组成的砂-橡胶混合物（SRMs）是典型的二元混合材料，具有多种复杂特性。当涉及复杂应力路径时，砂-橡胶混合物特性的复杂性会增加。本研究采用离散元方法研究了广义加载条件下砂-橡胶混合物的力学行为。对纯砂和砂-橡胶混合物进行了一系列数值真三轴剪切试验。研究了橡胶含量和加载路径对砂-橡胶混合物宏观和微观性能的影响，并探讨了相关的微观机理。数值模拟表明，峰值摩擦角ϕp与中间主应力比b之间的关系受橡胶颗粒添加的影响，对此现象的一种解释是橡胶颗粒主要影响强网络的固有稳定性。本研究还给出了颗粒尺度的观测结果，包括配位数、强接触比例和结构各向异性。微观结果证实了上述解释，并探讨了广义加载条件下砂-橡胶混合物的力传递特性。本研究可为砂-橡胶混合物本构模型的发展提供参考。
