Influence of particle shape on small-strain damping ratio of dry sands

This study reports on the significance of particle shape on the small-strain damping ratio of dry sands in shear (D-s,D-min) through a comprehensive set of torsional resonant column tests. Sands with a variety of grain shapes prepared at variable initial densities are studied. The samples are subjected to torsional resonant column tests under isotropic confining pressures (p') ranging from 50 to 800 kPa. Small-strain damping ratios are derived based on the free-vibration decay mode of the samples and the results are compared with the half-power bandwidth method. The effects of grain size distribution, particle shape and effective confining stress on D-s,D-min are thoroughly discussed, and a new model for the prediction of small-strain damping ratio of dry sand is proposed.