The use of compressional and shear wave velocities to measure the shear strength of soil

Abstract

Compressional and shear wave velocities have been measured in soil contained in a rigid-walled cylinder in both the axial and radial direction. This oedometer cell was fitted with a piston so that the soil could be axially compressed. The velocities and axial strain in the soil were measured as the axial stress was increased from zero to 35 lbs./sq. in. Measurements were made on both dry and wet soil. The axial and radial velocities were used to determine the radial stress. The ratio of the radial to axial stress gave the coefficient of earth pressure at rest and the angle of shearing resistance. For both the wet and dry soil, this angle was approximately 33 degrees. The velocities in wet and dry soils had approximately the same dependence upon axial stress, but the wet soil was much more compressible than the dry soil. Both wet and dry compressed soils maintained their strain and strained velocities upon decompression. However, when water was introduced into the decompressed soil, it expanded significantly and the velocities dropped to their precompression values. [Work supported by the USDA.]