Abstract:In order to find out the qualitative and quantitative relationships between triaxial tensile strength and triaxial shear strength,contrast experiments are carried out including triaxial tensile,triaxial shear and uniaxial tensile with remolded samples of unsaturated clay in core wall of Heihe Dam in Xi¢an,Shannxi province under different moisture contents. The experimental results show that:(1) the shear intensity index of unsaturated clay c and j decrease with the increasing of moisture contents;(2) though triaxial or uniaxial experiments of unsaturated clay,the Mohr circle,which is decided by confining pressure as major principal stress and axial stress as minor principal stress,accords with Coulomb criterion;and (3) there is functional relationship between tensile strength and shear strength of different unsaturated clay samples with same physical nature. Based on these conclusions,tensile strength of unsaturated clay can be estimated through results of shear tests without tensile strength test conditions.