Frequency and moisture content effects on the visco-elastic characteristics of soil

Cylindrical soil samples of varying moisture contents (13.1 to 21.7% dry basis) were subjected to sinusoidal excitations of seven frequencies (300 to 2000 Hz). Wave propagation theory was extended to three-dimensional in situ testing. In situ experimentation involved recording accelerations from an input source and measuring the output response on a plane perpendicular to the input for both horizontal and vertical directions. Moisture content did not have a significant effect on soil deformation within the range of moisture contents examined. Soil deformation was dependent upon excitation frequency. The relative deformation of soil in situ was measured for three different input excitation and output response orientations. Poisson's ratios for three dimensions varied by input-output orientation due to anisotropy of the soil.