Effect of variation of principal stress orientation on undrained dynamic strength behavior of loose sand

The geotechnical static and dynamic universal triaxial and torsional shear apparatus newly developed in Dalian University of Technology is used to perform experimental tests of loose sands with a relative density of 30% subjected to vertical-and-torsional coupling cyclic shear with rotation of principal stress axes induced by ocean wave and simple torsional shear. The effect of initial orientation of principle stress axes and the continuous change of principle stress direction under cyclic loading on dynamic strength behavior of Chinese Fujian standard sand under anisotropic consolidation condition is investigated. For anisotropic consolidation condition under different initial orientation of principal stress, two types of cyclic tests are conducted.