摘要
The development of offshore wind energy becomes very fast in recent years due to its clean, safe, and high efficiency. However, the issue that quite a few offshore wind farms have been built in seismic active areas raises a great engineering challenge for the selection, design, and seismic evaluation of offshore wind turbine foundations. Earthquake is one of the most critical hazards for offshore wind turbines. The softening of soil due to pore water pressure buildup can sharply reduce the bearing capacity of the foundation, and consequently result in stability failure. The induced strong structural vibration has adverse impact on the normal operation of wind turbine as well as on the efficiency of power generation. In this study, a group of earthquake centrifuge tests was performed on a physical model of a wind turbine with gravity foundation. The seismic behavior of both the structure and the foundation soil was analyzed based on the recorded accelerations, pore water pressures, lateral displacements and settlements. The emphasis was on the interaction between foundation and soil. The results showed that gravity foundation can effectively resist the overturning moment induced by the superstructure. However, it was quite sensitive to the subsoil conditions. The large settlement and tilt in the offshore foundation might affect the performance of a wind turbine.
