【摘要】 颗粒形状不仅反映颗粒的形成历史,更是影响堆石料物理力学性能的重要因素之一,值得深入研究。采用颗粒流程序PFC3D,根据实际颗粒形状建立不同球度的颗粒模型,并提出了数值试验中获取不同相对密实度试样的流程。讨论了球度对最大、最小孔隙比的影响,其结论与已有试验统计结果基本相符。分别以孔隙比和相对密实度为密度控制指标,对不同颗粒形状的试样进行等向固结和常规三轴试验,并分析了配位数、颗粒长轴各向异性、接触各向异性、结构各向异性等微观变量的变化规律。结果表明,当颗粒圆度较高且级配均匀时,球度对峰值摩擦角影响较小,主要影响残余摩擦角的大小。颗粒形状发生变化时,配位数影响试样强度但不起决定性作用,颗粒形状主要通过影响试样内接触以及接触力的各向异性程度来影响试样宏观表现。更多还原

【Abstract】 Aggregate shape not only reflects the formation history, but also plays an important role in the mechanical properties of granular materials, and the effect of aggregate shape deserves further study. In this research, the three-dimensional particle flow code,FPC3D, is used and five particle models are generated according to the actual aggregate shape. The process of obtaining different relative density samples in numerical experiments is proposed. The effect of sphericity on the maximum and minimum void ratio is discussed, and the conclusion is basically consistent with the statistical results of the existing experiments. Numerical tests of isotropic compression and triaxial compression are carried out on the samples consisting of different shape aggregates, and the void ratio and relative density are selected as density control indexes respectively. The evolution of four micromechanical indexes with strain including coordination number, particle orientation, deviator fabric and branch vector is studied. The data show that when the particles are well-rounded, the sphericity has less influence on the peak friction angle. Instead, it mainly affects the residual friction angle. When the aggregate shape changes, the coordination number affects the strength but does not play a decisive role. The particle shape mainly influences the macroscopic performance by affecting the degree of anisotropy of contact and contact force in sample.更多还原