Shear characteristics of steel pile-soft clay interface under cyclic loading

Recently, construction of offshore wind power has developed rapidly in China. However, the current design methods for the bearing capacity of pile foundations are often based on small-diameter flexible piles, which are not applicable to the real situation. At the same time, there are thick layers of clay in the field. Therefore, it is necessary to study the shear characteristics of the steel pile-soft clay interface to optimize the design method. The large-scale interface shear test model corresponding to the laboratory tests is established by using the numerical simulation software, and the values of the micro-parameters are validated. The simulated results fit the laboratory test results well, and the model can accurately reflect the pile-clay interaction during shearing. Based on this model, the shear characteristics of the steel-clay interface under different cyclic loading frequencies and amplitudes are analyzed. The results show that while the interface strength slightly decreases with the increase of the frequency and amplitude of cyclic loading, particularly the effects of the amplitude are more obvious. The mechanical response of clay from the mesoscopic scale is also analyzed. The greater the cyclic loading frequency and amplitude, the smaller the horizontal displacement of the particles. The research results can provide support to predict the bearing capacity of pile foundation of offshore wind power.