RING SHEAR TEST OF HIGH LIQUID LIMIT SLIDING ZONE SOIL UNDER DIFFERENT INITIAL SATURATION

This paper investigates the influence of initial saturation state on the residual shear strength characteristics of typical sliding zone soils by ring shear test. A series of ring shear tests were conducted on specimens with dry density of 1.20 g·cm^-3, 1.35g·cm^-3 under the axial loads of 100 kPa, 200 kPa, 400 kPa, and the relationship between residual shear stress and rotation angle was obtained. According to the residual shear stress obtained from experimental results and the Mohr-Coulomb failure criterion, the cohesion and friction angle were determined. The degree of saturation at initial state has no obvious influence on the residual strength under the normal stress of 100 kPa, but its decrease results in a decrease in residual strength under the normal stress of 200 kPa and 400 kPa. The residual cohesion increases with the increase of the degree of saturation at initial state under the dry density of 1.35g·cm^-3, but it firstly increases and then decreases when the dry density is 1.20g·cm^-3. The residual friction angle decreases with the increase of the degree of saturation at initial state. The decrease in dry density makes the residual strength parameters more sensitive to changes in the degree of saturation at initial state.