Bearing Performance of Single-Column Composite Bucket Foundations for Offshore Wind Turbines Under Scour Evolution
This study investigates the bearing performance of single-column composite bucket foundations under scour conditions through finite element analysis and scaled model tests. The most unfavorable scour scenario was identified by evaluating load angle effects on bearing capacity, frequency, and stiffness. Laboratory tests were conducted on a 1:60 scaled model of a 36 m diameter prototype foundation embedded in Tianjin clay, with scour depths ranging from 2 m to 10 m. Results indicate that when the load angle faces the scoured side, the ultimate bearing capacity reaches its minimum, with maximum stress concentrated at the bottom of the compartment plate on the scoured side. Lateral stiffness decreases by 15% and frequency by 7–8% as scour depth increases from 2 m to 10 m. Complete scour reduces bearing capacity by approximately 10%, while cyclic loading amplifies scour effects, significantly reducing horizontal stiffness and increasing cumulative rotation. The foundation's bearing mechanism primarily relies on internal soil and base support. Scour protection measures such as rock dumping, geotextile, and fender systems are predicted to restore stiffness to over 90% and bearing capacity to over 95% of unscoured values.