Experimental Study on the Sinking and Leveling of A Large-Capacity Offshore Wind Turbine Five-Bucket Foundation in Sand

As offshore wind farms expand into deeper and farther ocean regions and the unit capacity of offshore wind turbines (OWTs) increases, there is a pressing need for a new foundation structure that can accommodate deep-sea conditions and support large capacities while maintaining economical and safe. To meet this goal of integrated transportation and one-step installation, a novel five-bucket jacket foundation (FBJF), with its suction installation and leveling methods in sand, has been proposed, analyzed and experimentally studied. First, seepage failure experiments of the FBJF at various depths were conducted, and a formula for calculating the critical suction of seepage failure suitable for the FBJF in sand was chosen and recommended for use with a range of values for the permeability coefficient ratio. Second, through leveling experiments of the FBJF at different depths, the maximum adjustable leveling angle during the sinking process was defined using seepage failure and the adjustable leveling angle of the foundation as control criteria. Various leveling control strategies were proposed and verified. Finally, an automatic sinking and leveling control system for the FBJF was developed and experimentally verified for feasibility.