考虑部分埋入群桩基础阻抗的海上风机结构共振特性

Resonance characteristics of offshore wind turbine structures founded on partially embedded pile groups

海上风机结构一阶自振频率与风轮转动频率或叶片通过频率重合时,会产生共振现象,严重时会造成风机损坏。现有风机结构的共振研究多假设底部刚性固定,以定性分析为主,没有对基础的埋置深度和土层参数进行量化分析。以部分埋入群桩基础的海上风机结构为研究对象,基于风机结构水平–摇摆耦合简化方法,分析了群桩基础不同埋入比和土层弹性模量对风机结构共振特性的影响,建立了群桩埋入比与结构共振频率的关系。进一步开展了4组不同群桩埋深比的海上风机共振频率室内模型试验,验证理论分析结果的规律性是否合理。

Resonance occurs when the first natural frequency of wind turbines coincides with frequencies of the rotor rotation and blade passing,which may cause damage to wind turbines in serious conditions.Most existing researches on the resonance of wind turbines are qualitative analysis,assuming a rigid and fixed structure bottom.However,the quantitative analysis is important,especially considering the effect of foundation embedment depth and soil parameters.The resonance of offshore wind turbines supported by partially embedded pile groups is investigated.Based on the simplified method considering the coupled horizontal-rocking properties of wind turbines,the influences of different embedding ratios of pile groups and the elastic modulus of soils on the resonance of wind turbines are analyzed,providing the relationship equation between embedding ratios and resonance frequencies.To investigate the resonance frequencies of offshore wind turbines with different embedding ratios of pile groups,four model tests are carried out,which verify the rationality of the above theoretical analysis.