Strength and Deformation Characteristics of High Plasticity Offshore Clay

The purpose of this study is to investigate the shear strength and stiffness characteristics of high plasticity offshore clay. A series of undrained monotonic triaxial compression and direct simple shear tests was conducted on reconstituted saturated offshore clay specimens. The clay specimens were tested under different confining pressures and overconsolidation ratios (OCR 1, 2, 4, 10 and 40) at constant dry density of about 1.25g/cm3. The offshore clay exhibits contractive behaviour. The test results show that an increase in OCR increases the normalized deviator stress and stiffness of the offshore clay. The normalized stiffness increases with increasing OCR but decreases with increasing axial strain. The normalized shear strength of high plasticity offshore clay increases with increasing strain rates.