Coupling cyclic tests on saturated clay under different waveforms

The cyclic rotation of the principal stress direction with constant amplitude was the characteristics of the cyclic stress in seabed deposit induced by waves.The apparatus for the static and dynamic universal triaxial and torsional shear soil tests was employed to perform stress-controlled cyclic coupled vertical and torsional shear tests under different waveforms of imitated waves.Through a series of tests on saturated clay,the dynamic strength,dynamic deformation behavior,general critical cyclic stress ratio and Lode parameter of stress were systematically investigated under sinusoid and triangular waves.Based on the experimental results,it was observed that the dynamic strength of saturated clay under sinusoid waves was less than that under triangular waves with the same failure cyclic number;the dynamic deformation under sinusoid waves was larger than that under triangular waves in the same dynamic shear stress;the effect of different waveforms on the general critical cyclic stress ratio under sinusoid waves was less than that under triangular waves.Moreover,the variation of Lode parameter of stress was discriminative between two types of waveforms.