Deformation and Failure in Wet Clay Soil: Part 1, Stress-Strain Relationships

Abstract

Uniaxial and triaxial compression tests, unconfined tension tests and direct shear tests were undertaken to investigate the behaviour of wet clay soil under quasi-static conditions. In addition to measurement of force-displacement relations, the soil deformation pattern was carefully observed and analysed with the help of a painted grid method. In the compression tests and direct shear test, the soil failed in shear with pronounced distortion; in the tension test, soil samples were broken by tensile cracks perpendicular to the tensile stress. In the compression tests and tension test the deformation non-uniformity was not significant at low to medium strains but became large when the soil was close to failure. Four kinds of formulae were fitted to the experimental stress-strain curves and a hyperbolic formula was found to give the best fit.