Experimental study on coupling effects of cyclic confining pressure and intermittent cyclic loading on deformation behavior of saturated soft clay

The deformation characteristics of soft clay under intermittent cyclic loading and cyclic confining pressure are studied by conducting two types of cyclic triaxial tests, i.e., continuous cyclic loading and intermittent cyclic loading triaxial tests, and the influences of cyclic confining pressure and intermittent period on the accumulated axial strain of soft clay are analysed. The test results show that compared with the continuous cyclic loading conditions, the existence of intermittent period has a significant effect on the deformation characteristics of soft clay, and the deformation caused by the dissipation of the excess pore water pressure during the intermittent period cannot be ignored. On the other hand, with the increase of the cyclic confining pressure, the corresponding accumulated axial strain increment is small. The difference of the increment of accumulated axial strain under different cyclic confining pressures is significant during the cyclic loading period at the first loading stage, and can be ignored at the subsequent cyclic loading stage. Based on the above test results, a model for the accumulated axial strain of soft clay under intermittent cyclic loading considering the effects of cyclic confining pressure is proposed, and the predicted results are in good agreement with the measured data. The above research results can deepen the understanding of the deformation behavior of soft clay under intermittent cyclic loading.