Transient Response Characterization of Wind Turbine Structure–Extended Foundation Under Wind Loading

To study the transient response characteristics of wind turbine structures–extended foundations under wind loads in mountainous areas, this paper develops a simplified analytical model based on soil–structure interaction theory. It explores the effects of constraint conditions, wind speed, and foundation shear wave speed on the transient response behavior. By analyzing the time–domain and frequency–domain trends of tower top displacement, foundation horizontal displacement, and foundation rotation angle, the relationship between foundation shear wave speed and the safe wind speed of the wind turbine is clarified. The results indicate that different constraint conditions lead to variations in the calculated resonance frequency, maximum tower top displacement, and acceleration response spectrum. Furthermore, based on the analysis of the tower top acceleration response curve, the influence interval of frequency can be categorized into three distinct ranges: stable range, small influence range, and large influence range. Wind speed primarily influences the vibration amplitudes of the three displacement components, while the overall trend of the time-displacement waveform remains unchanged. The foundation shear wave speed primarily affects the displacement of the foundation itself, exerting a smaller influence on the displacements of the wind turbine structure. Notably, the total displacement at the tower top decreases as the shear wave speed increases. Moreover, the safe wind speed of the wind turbine shows a positive correlation with the foundation shear wave speed, indicating a linear relationship between the two variables.