Local Scour Characteristics of the Seabed Around Offshore Wind Power Pile Foundations

• • Maximum scour depths of 7–8 m at 25# (8.0 m pile diameter) and 5–6 m at 55# (6.5 m pile diameter) were measured, directly reducing effective embedment depth and compromising vertical and lateral bearing capacity; this magnitude of scour can lower the natural frequency of the monopile support structure, risking resonance with rotor excitation and accelerating fatigue damage. • • Scour pit length and maximum scour depth exhibit a strong linear correlation, enabling rapid estimation of scour extent from limited bathymetric data; this relationship is critical for designing cost-effective scour protection and scheduling maintenance in large wind farms where comprehensive surveys are prohibitively expensive. • • The scour pits evolved from December 2021 to September 2022 through initial scour followed by deposition, with net scour overall; scour concentrated at the pit periphery while deposition occurred near the pile, indicating dynamic sediment transport pathways that must be accounted for in long-term foundation stability assessments. • • Typhoon Muifa in September 2022 caused partial backfilling of the scour pits, demonstrating that extreme weather events can temporarily mitigate scour but may also induce rapid morphological changes; this underscores the need for post-typhoon surveys to reassess foundation integrity and adjust protection strategies.