砂质海岸单桩基础的冲刷特征与防护措施试验研究

Experimental Study on Scour Characteristics and Protection Measures for Monopile on Sandy Coast

[目的]海上风电开发的一个重要环节是建造合适的海上风电基础支撑结构,近年来,单桩结构成为海上风电机组的主要基础形式。单桩基础在海洋环境中的局部冲刷问题对风机结构的稳定性有重要影响。[方法]通过开展系列物模试验,对某建于砂质海床并采用大直径单桩基础的风电场工程的桩基局部冲刷特征进行了研究,分析了不同直径、水深、波浪以及水流等因素对局部冲刷深度和范围的影响,并研究了砂被和沙袋等措施的防护效果。[结果]研究结果表明,对于直径7.0 m和6.5 m两种桩基,冲刷最深处均在单桩迎水面,最大冲刷深度为桩基直径的0.8~0.9倍。[结论]采用无搭接方式铺设砂被并且采用沙袋填充冲刷坑可对桩基结构周围底床形成很好的防护,可为同类工程冲刷试验和工程设计提供参考。

[Introduction]Constructing the proper wind turbine foundation is important during the construction of offshore wind farm,and the monopile has been one of the main structures for the wind turbine foundation in recent years.However,the local scour problem for the monopile under marine environment has significant influence on the stability of the wind turbine structure.[Method]In this paper,for one actual wind farm project on sandy coast,the physical model tests were conducted for the local scour of the monopile for different water levels and pile diameters to analyze the effect of wave and current on the scour depth,to study the scour area and depth under the action of combined wave and current,and the protection effect of the sand blanket and sandbag.[Result]The result showed that,for the two monopiles(diameters of 7.0 m and 6.5 m),the locations of maximum scour depth are both at the upstream face,and the maximum scour depth is about 0.8~0.9 times of the pile diameter.[Conclusion]The measure of laying sand blankets without overlapping and filling scour pits with sandbags can protect the bottom around the pile foundation very well,which can provide references for similar engineering scour test and engineering design.