Local Scour Characteristics of the Seabed Around Offshore Wind Power Pile Foundations
This study investigates local scour around monopile foundations at an offshore wind farm in Dafeng, Jiangsu, China, using four multibeam bathymetric surveys conducted between December 2021 and September 2022. The scour pits exhibit a funnel-shaped three-dimensional morphology with an elliptical planform, the major axis aligned with the NNE-SSW tidal current direction. Maximum scour depths reach 7–8 m at turbine position 25# (pile diameter 8.0 m) and 5–6 m at position 55# (pile diameter 6.5 m), consistently occurring on the leeward side facing the ebb current. A strong linear correlation exists between scour pit length and maximum scour depth. The evolution from December 2021 to September 2022 shows initial scour followed by deposition, with net scour overall; scour concentrates at the pit periphery while deposition occurs near the pile. Typhoon Muifa in September 2022 caused partial backfilling. Given the substantial dimensions and depths of the scour pits, extending bathymetric monitoring to all turbine positions and implementing timely scour protection measures are recommended to prevent further pit development. The findings provide a reliable field-data basis for understanding local scour mechanisms in similar offshore wind projects.