Abstract: Using the sinusoid and triangular waves to simulate the loading form of ocean wave, we carried out a series of tests of cyclic rotation of principal stress axis with GCTS hollow cylindrical torsional apparatus for soft dredged fill of Tianjin Binhai under the condition of triaxial isobaric consolidation. The effects of cyclic shear stress amplitude and vibration wave on the generalized shear strain, dynamic strength and pore pressure of the dredged fill under the continuous rotation of dynamic principal stress direction were discussed. The test results indicate that when the amplitude of cyclic shear stress is less than the critical cyclic shear stress, the generalized shear strain has little change and grows slowly. The loading waveform has little influence on the deformation. When the amplitude of cyclic shear stress exceeds the critical cyclic shear stress, soil mass deforms greatly with less cyclic number. It is observed that the development rate of generalized shear strain under sinusoid wave is greater than that under triangular wave, and the corresponding generalized shear strain under sinusoid waves is always greater than that under triangular waves with the same cyclic number. Under the same waveform, the larger the value of failure criterion is, the larger the value of dynamic strength is. The dynamic strength decreases under different failure standards with the increase of failure cyclic number, and finally they tend to the same value. In the same conditions, sinusoid wave is more likely to cause soil damage than triangular wave under the effect of cyclic rotation of principal stress axis. Based on the analysis of the test data, we established the relationship between the dynamic strength and the failure cyclic number with the two kids of waveform under the different failure criteria. Under the same conditions, the growth rate of pore pressure of sinusoidal wave is higher than that of triangle wave. And the larger the amplitude of cyclic shear stress, the faster the rate of pore pressure growth. However, due to the hysteresis effect of pore pressure of cohesive soil, the value is relatively small when the failure strain is reached.