Shear strength-suction relationship of compacted Ankara clay

The relationship between shear strength and soil suction of compacted Ankara clay was investigated at different moisture contents. Soil samples were tested at optimum moisture content (w = 20.8%), drier than optimum (w = 14.8%, 16.8%, 18.8%) and wetter than optimum (w = 22.8%, 24.8%, 26.8%). Direct shear tests were performed. Soil suctions were measured by the filter paper method after direct shear tests. Direct shear tests and soil suction measurements were also performed on soaked samples. The soil suction versus moisture content curve was developed. The shear strength variation with respect to soil suction was found for all normal stresses. The soil suction versus moisture content curves bear a close relationship to the unsaturated shear strength of the soil. An increase in soil suction increases the shear strength.