Session: 10-03-01 Anchoring and Mooring Systems

Paper Number: 128304

128304 - A Novel Drag Anchor Design for Enhanced Penetrability and Holding Capacity 

The offshore wind is a booming industry and as the industry advances into deeper waters, floating offshore wind is gaining increasing popularity. However, compared to bottom fixed offshore wind, floating wind is much more expensive as of now therefore cost reduction is a key to maturity of the floating wind industry. Drag anchors are appealing anchoring solutions for floating offshore wind turbines due to their high holding capacity ratios and relative low cost for installation. The holding capacity of a drag anchor is to a large extent dictated by the penetration depth achieved during installation. In hard soils, such as sand, the penetration depth of drag anchor is often limited to about one fluke length due to rapid rotation of the anchor caused by large soil resistance encountered on the shank. In this paper, a novel drag anchor design which greatly reduces the soil resistance on the shank is proposed in a hope to improve its penetration depth and consequently the holding capacity. To verify the design, a comprehensive suite of large deformation finite element analyses in both sand and clay soils and scaled model tests in sand are carried out using both Vryhof Stevepris MK6 design and the proposed anchor design. Both the numerical analyses and the model tests confirm the design hypothesis. Structural aspects for the novel anchor design are also briefly discussed.

Presenting Author: Youhu Zhang Southeast University

Presenting Author Biography: Dr Youhu Zhang is a professor in geotechnical engineering at Southeast University, China. He previsouly worked at the Norwegian Geotechnical Institute from 2013-2021. He has a long experience in research and enginering consultancy in offshore soil charterisation and foundation design for offshore structures.

Authors:

Youhu Zhang Southeast University
Shuzhao Li CNOOC Beijing Research Institute
Xiangyu Wang Southeast University
Chuheng Wu Southeast Uniersity
Peng Guo Southeast University
Di Lei Southeast University