2024 Volume 80 Issue 18 Article ID: 24-18032
Rocks and stones are widely used to prevent scour around monopiles of offshore wind turbines. In order to reduce the construction period by bulk construction, it is possible to consider using large-sized, water-permeable, high-strength geotextile with continuous chains as a scour protection measure instead of rocks and stones. In this study we treated the sheet laid on the seabed as a rigid body, and performed numerical experiments using CADMAS-SURF/3D V1.5 to investigate the uplift force exerted on the sheet by waves. For the impermeable sheet, a significant uplift force is generated when there is even a small gap between the sheet and seabed surface. A permeable sheet will experience less uplift force than an impermeable sheet, and a significant reduction in uplift force can be achieved by further minimising the gap between the sheet and seabed surface. For this reason, chains or similar materials that can easily follow deformation are suitable as the weight on the seat. The mass of the chains required for the permeable sheet is sufficient about at 1/20th of that for the impermeable sheet, indicating a significant advantage of the permeable sheet.
