An experimental study of the local scour protection methods around the monopile foundation of offshore wind turbines

Local scour induced by current or wave is a significant factor impacting the overall stability and fatigue life of the pile foundation of wind turbines. Currently, the most commonly used scour protection method is the rock armour, which works by placing rocks on the original seabed to reduce the near-bottom flow speed. Although the rock armour is easy to be implemented in practice, it still has the potential of complete failure due to the washout near the structure and along the outer edge. In this study, we investigate the performance of four different scour protection methods through physical experiments, which include rock amour, sand-ribbed geotextile mattress (SRGM), bionic grass, and honeycomb structure. The results indicate that the sand-ribbed geotextile mattress is the most effective among all test scour protection methods. However, given its relatively high potential to impact local environment, careful and thorough consideration should be taken before the practical implementation.