Numerical Simulation Analysis Of Offshore Wind Power Structure Considering Pile-soil Interaction

While considering pile-soil interaction, p-y curves that is recommended by the API specification can consider nonlinear characters of pile-soil interaction, the modal analysis of commonly used finite element software is kind of linear dynamic analysis, which is not ready for nonlinear analysis. Nevertheless, the points that compose the p-y curves may represent the stiffness of soil, in other words the curve can represent the changing trend and variation range of soil’s spring stiffness. In this, variation range of soil’s stiffness was obtained by making most of p-y curves, and spring element was chose to simulate the pile-soil interaction in some researchers’paper, based on these, the natural vibration characteristic of the pile-soil overall structure was analyzed.However, in view of the modal analysis of offshore wind power structure, previous studies have not deeply studied the method that how to determine the suitable soil stiffness, or how to determine the suitable.y1 value of p-y curves. However, the selection of y1 value is appropriate or not will affect the natural frequency value of the pile-soil overall structure to a great extent. This paper studies and puts forward two methods to determine the appropriate y1 value from the angle of time domain and frequency domain respectively. This research provides a more scientific and precise method to determine the y1 value during the modal analysis of offshore wind power structure which is based on the p-y curves.Finally, based on the time-domain method proposed in this paper, p-y curve method is deducted by Cu to consider pile-liquefied soil interaction, the modal analysis results will be compared in the cases of considering liquefaction and not considering liquefaction.