Shear wave velocity of granular mixtures of silica particles as a function of finer fraction, size ratios and void ratios

This experimental investigation quantified the shear wave velocity of granular packs composed of large grains mixed with small quantities of finer grains, up to the critical fines content (). Bender element tests were performed on 112 mixtures to quantify the variation of with fines content (FC), particle size ratio, and void ratio. When FC was less than , the shear wave velocity decreased with increasing FC, due to the reduction in interparticle contacts between large grains. In addition, the observed reduction in packing stiffness was more apparent as the size difference between the two particles increased. Most notably, the results of this study demonstrated that of granular mixtures of two different silica particles with was best expressed in terms of intergranular void ratio when finer particles were treated as void space, as opposed to the global void ratio.