In the previous studies, the cyclic triaxial tests under intermittent cyclic loading are used to study the deformation characteristics of soft clay under traffic loads. Both confining pressure and deviator stress vary cyclically in the stress field under traffic loads. The pore water in the soil can be discharged during cyclic loading and intermittent periods. Therefore, two types of cyclic triaxial tests are performed on soft clay, i.e., cyclic triaxial tests with intermittent cyclic loading are undrained and partially drained conditions. The deformation characteristics of soft clay under intermittent cyclic loading were studied, and the effects of cyclic confining pressure and drained conditions on the accumulated axial strain are analyzed. The test results indicate that the accumulated axial strain is significantly affected by the cyclic confining pressure and drained conditions. The strain increment decreases with the increasing loading stage, but the attenuation degree of strain increment varies under different cyclic confining pressures. The strain increment increases as the cyclic confining pressure increases under partially drained conditions, while decreases under undrained conditions. Besides, compared to that under undrained conditions, the attenuation degree of strain increment is more significant under partially drained conditions. Meanwhile, the difference in the strain increment under different test conditions is more pronounced at the first loading stage, and can be ignored at subsequent loading stages. Based on that, a formula for predicting the accumulated axial strain of soft clay under intermittent cyclic loading considering the influences of cyclic confining pressure and drained conditions is proposed, and the predicted results are in good agreement with the measured values. The above research results contribute to a deeper understanding of the mechanical properties of soft clay under intermittent cyclic loading.
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