关键词: 离散元法, 颗粒形状, 堆积密度, 强度, 微观参数

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.

Key words: discrete element method, particle shape, packing density, strength, microscopic parameters