考虑冲刷效应的大直径单桩式海上风机结构振动响应特性研究OA

Scour of pile foundations is a critical factor influencing the dynamic characteristics of large-diameter monopile offshore wind turbine structures.Studying its impact thoroughly and developing effective detection methods are very important for ensuring the safe operation of these structures throughout their entire lifetime.This study focuses on a 10 MW large-diameter monopile offshore wind turbine structure.Through numerical simulations of vibration tests,free vibration response signals of the structure under ice load were obtained and analyzed in multiple dimensions,including time domain,frequency domain,and time-frequency domain,to deeply explore the influence patterns of scour on the vibration characteristics of the structure.Based on this,two detection indicators-energy change ratio and mean value of peak coherence function-were established for qualitative and quantitative detection of pile scour.The results indicate that vibrations within the second modal space of the large-diameter monopile structures cannot be overlooked.Scour leads to a reduction in the natural frequencies of the structure,with a more significant impact on the second and third frequencies than on the first,particularly in sandy soil.The energy of the structural vibration response increases with the development of scour,while the decay rate of the second-order vibration component slows down.Both detection indicators show monotonic relationships with scour depth,making them suitable for qualitative and quantitative detection of scour in large-diameter monopiles.Furthermore,the influence of pile foundation embedment depth on the sensitivity of structural dynamic characteristics to scouring cannot be overlooked.It is recommended to comprehensively consider this factor along with bearing capacity in pile foundation design.