Model test on bearing capacity and accumulated settlement of single pile subjected to axial cyclic loading

The performance of the single pile under cyclic loading is different from that under static loading. A series of large scale model tests on cyclic axial response of the single pile in silt are described in this paper. The tests are carried out by use of the large foundation and slope engineering test system of Zhejiang University. Accumulated settlement of the pile is measured for different cyclic loading levels. A critical value of the cyclic axial loading ratio termed the minimum cyclic loading ratio is defined. Below this threshold value the pile performance will not be significantly affected by cyclic loading. It is found that the accumulated settlement of the pile is proportional to the number of loading cycles, and the ratio of accumulated settlement of the pile and number of loading cycles is varied linearly with the cyclic loading ratio. With the given failure criteria of the pile subjected to the axial cyclic loading, the cyclic bearing capacity curve of the pile is presented. It is seen that the accumulated settlement of flooding is more than that of the end bearing pile under cyclic loading. The non-dimensional settlement of the pile is proposed, and it can be used to predict the accumulated settlement of the pile in-situ. A design method of the pile under long-term cyclic axial loading is finally presented.