Penetration installation of the13-compartment mono-column composite bucket foundation for offshore wind turbines

Abstract

The 13-compartment mono-column composite bucket foundation, which will be abbreviated as "The 13-compartment MCCBF" in the following text, has stronger applicability to the shallow bedrocks and plays an important role in the development of wind farms in the South China Sea with more shallow bedrocks. This paper studies the penetration installation characteristics of 13-compartment MCCBF under four geological conditions: pure sand, clay over sand, sand over shallow bedrock, and clay over shallow bedrock. Through a 1:60 scale model test, the variation law of the pore water pressure around the foundation during its penetration installation was analyzed, the morphological changes of the surrounding soil and the development law of soil plug after the foundation installation were explained, and the required penetration suction of the foundation under different geological conditions was explored. The research results show that during the penetration installation of the foundation, the required pressure difference increases with the increase of the penetration depth, the pressure of the compartment in the overlying clay geology is higher than that in the overlying sand geology, with a difference of about 3–5.5 times. The penetration installation speed of the foundation in the shallow bedrock geology is faster, about 1.6–5 times that of the geology without shallow bedrocks. The volume of seepage water in the sand over shallow bedrock geology is about 50 % of that in the pure sand geology. Soil plug will be formed in the process of foundation penetration, among which the soil plug is the highest in the sand over shallow bedrock geology.