Dynamic characteristics analysis of three-bucket jacket foundation lowering through the splash zone

Abstract

The offshore wind turbine three-bucket jacket foundation (TBJF) bears some complex force at the stage of lowering though splash zone, and two nonlinear phenomena appear in the bucket foundation: The air cushion structure is formed in the bucket and generates a slamming force on the roof. This paper point at two nonlinear phenomena, the model tests research on the lowering and installation of the TBJF are carried out. The effects of waves and control conditions on air cushion response, the variation law of sling tension and the dynamic characteristics of foundation are investigated. Moreover, the calculation formula of air pressure during foundation lowering process on comprehensively considering various factors to be deduced. In contrast to the experiment tests, the contraction coefficient is revised. In addition, different theoretical analysis models of slamming load on roof during lowering process are established. The influence mechanism of the foundation structure, perforation ratio and lowering speed on the response of air cushion structure and slamming load are revealed. Meanwhile, the attitude control mode during the lowering process of the TBJF is defined. This study provides a theoretical basis for the optimization of foundation installation construction technology and cost control.