Split-Hopkinson Pressure Bar Testing of Unsaturated Sand
High amplitude, split-Hopkinson pressure bar (SHPB) laboratory tests were conducted on compacted specimens of 50/80 silica sand to evaluate the influence of saturation on compressional-stress wave velocity, stress transmission, and attenuation. Stress wave velocity and transmitted stress increase as the saturation increases from 0 to 30 to 40% for constant input stress and constant dry density. At saturation levels between 40 to 95%, both the wave speed and the transmitted stress decrease with increasing saturation. Quasistatic confined modulus show similar trends. These trends may be explained by capillary pressure.