Fluid Wave Propagation in Saturated and Nearly Saturated Sands

Impacts at the end of a 4-ft (1.22-m) long test chamber developed compression waves in saturated and nearly saturated sands. The wave velocities depended upon the void ratio, void size, particle compressibility, particle shape, specific gravity, and degree of saturation. Of these variables, degree of saturation was the most important. A decrease from 100% to 99.7% saturation could reduce the wave velocity by a factor of two. The time to reach 100% saturation, from about 99% saturation, was on the order of one month when the fluid pressure was 75 psi (517.5 kN/m²). These results indicate that sand embankments adjacent to tidal zones or reservoir fluctuations are probably not completely saturated. Thus, propagation of compression waves in the pore fluids of such structures will be reduced below the fully saturated values.