Effects of intergranular friction and grain size distributions on the initial void ratio of granular sample

This paper investigates the influence of intergranular friction and grain size distributions on the initial void ratio of a granular sample subjected to isotropic compression loading. In the field of geomechanics, besides the loading path and evolution of microscopic properties, the initial void ratio is a crucial and key factor that governs the mechanical behavior of geomaterials. By using Discrete Element Model (DEM) performed on an idealized 2D assembly of disks, this study demonstrates that the initial void ratio can be affected by several parameters during isotropic compression stage. By varying a wide range of intergranular coefficients of friction and grain size distributions, our numerical results suggest that increasing the intergranular coefficient of friction during the isotropic compression phase leads to looser samples. Furthermore, when the diversity of grain sizes is rich, smaller grains can move and occupy voids, thereby increasing the density of the granular sample. A power-lawrelationship is then proposed that connects the minimum void ratio and the diversity degree of the sample.