Evaluation of effective soil density in resonant column tests

This paper presents a theoretical study of effective soil density for small-strain shear wave propagation in saturated soil specimens in resonant column tests. Effective soil density is a term used to consider the fraction of pore water that moves with the solid skeleton during shear wave propagation. The ratio of effective soil density to saturated soil density is always and is a function of porosity, specific gravity of solids, hydraulic conductivity, and shear wave frequency. In resonant column tests, the transition of effective density from the maximum value (i.e., saturated density) to the minimum value occurs primarily in coarse sands. In this region, the consideration of effective density is important in capturing the first resonance and interpreting resonant column test results. For soils less permeable than coarse sands (e.g., clays, silts, and fine sands), the consideration of effective density is not important and the saturated density can be used. For soils more permeable than coarse sands (e.g., gravels), the effective density is significantly less than the saturated density.