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

Abstract

[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.

Keywords

• sandy coast
• monopile foundation
• local scour
• physical model test
• protection