Moisture effects on the high strain-rate behavior of sand

The effects of moisture content on the high strain-rate mechanical properties of fine grain sand were characterized with a split-Hopkinson pressure bar. A controlled loading pulse allowed the sample to acquire stress equilibrium and a constant strain-rate of 400 s−1. The sand specimen confined in a hardened steel tube, had a dry density of 1.50 g/cm3 with moisture contents varied from 3% to 20% by weight. Experimental results indicate that partially saturated sand is more compressible than dry sand with the softest behavior observed at 7% moisture content. The softening of the partially saturated sand may occur due to the pore water acting as a lubricant between the sand particles. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions.