Combined recovery technology of pile foundations for offshore wind turbines

Abstract

In recent years, offshore wind turbines have rapidly developed, and many pile foundations installed earlier are now approaching decommissioning. Thus, the efficient removal of pile foundations has become a critical issue for the sustainable development of offshore wind energy. To address this issue, this paper systematically investigates three methods for the recovery of pile foundations using physical model experiments: water injection + lifting, air injection + lifting, and air retention + water injection. The experimental results show that the water injection + lifting method exhibits remarkable advantages in recovering large-diameter and inclined pile foundations; however, realigning inclined piles during recovery remains challenging, and a risk of pile overturning exists. The air injection + lifting method proves effective for realigning inclined piles but presents a risk of air expulsion failure, which may affect the continuity and stability of the recovery process. By contrast, the air retention + water injection method combines the characteristics of water injection and air injection techniques, effectively avoiding air expulsion failure and exhibiting pronounced displacement jumps during pile uplift. These findings provide a valuable reference for future decommissioning practices of offshore wind pile foundations, offer important engineering application value, and contribute positively to the sustainable development of the offshore wind industry.

Keywords

offshore wind turbine / pile foundation / recovery / physical model experiment

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Funding

The National Natural Science Foundation of China(52171274)