Quantifying the uniformity of granular mixtures through a study on small-strain stiffness via DEM

The conventional uniformity coefficient Cu fails to capture the uniformity of gap-graded granular mixtures. To address this limitation, this study introduces a new index Cu m for quantifying mixture uniformity based on their small-strain stiffness G0. Granular mixtures with varying fines content (FC) and particle size ratio (PSR) were prepared, and their G0 values were determined through quasistatic drained triaxial tests. The corresponding Cu m values were then derived from the measured G0 values and expressed as a function of FC and PSR. The rationality of the proposed Cu m was verified, and it was further demonstrated that Cu m can be used to predict the small-strain stiffness of granular mixtures when the mechanical coordination number (CNm), particle shear modulus of particles (Gp), confining stress (O0) and Cu m are known.