Impact compressive response of dry sand

A split Hopkinson pressure bar (SHPB) was properly modified to obtain dynamic compressive stress–strain curves of dry sand at various high strain rates. Quasi-static compressive properties of the sand were obtained with a MTS810 materials test system. In both dynamic and quasi-static experiments, the 1.50 × 103 kg/m3 dry sand, confined with a polycarbonate tube, had the same dimensions, making the strain rate the only variable. The strain rate effects on the compressive response of the sand were determined. The sand was also prepared to specimens with a higher initial density of 1.62 × 103 kg/m3 for dynamic experiments to investigate the initial density (gas porosity) effects. At a given dynamic strain rate, besides using the polycarbonate confining tube, polyolefin heat shrinking tubes and 4340 steel tubes were used to confine the sand specimens to study the lateral confinement effects. The results show that the compressive response of the dry sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the initial density and lateral confinement level.