Size effects on the void ratio of loosely packed binary particle mixtures

摘要

Studies of binary particle mixtures provide useful insight into the effects of fine particles on the void ratio of natural multi-sized geomaterials. The relative amount of fine particles in a mixture significantly changes the void structure and influences the behavior of such materials. This paper presents complimentary experimental evaluations and numerical simulations that show how void ratios change non-linearly as additional fine particles are included in binary mixtures. Experimental results for a range of particle size ratios are presented. The paper also demonstrates that there are particular percentages of fine particles by weight at which the lowest values of void ratio are achieved. Loosely packed binary mixtures are simulated by a gravitational sphere packing method to further examine the effect of different weight percentages of fine particles on the void structure. The numerical studies are based on Monte-Carlo simulations wherein spherical particles are randomly packed. The complex pore structure obtained by random packing prevents any pre-defined or repetitive packing arrangements, which can lead to the computation of non-representative void ratio values. Results obtained from the numerical simulations are compared with experimental results and confirm the viability of the gravitational sphere packing method to efficiently reproduce realistic packed soil particle systems.