Investigating vibro-driven monopile installation into sand in a geotechnical centrifuge

Bottom-fixed foundations currently dominate the offshore wind market. The installation of monopiles for offshore wind turbines by vibration is a promising alternative to the conventional impact-driven technique. Despite being a low noise, time-efficient and cost-effective alternative, take-up of this method has been slow because uncertainties remain on the pile drivability and post-installation performance of vibro-installed monopiles, which translates to risk for the industry. Carrying out real scale field tests to increase understanding is extremely expensive and time-consuming. In contrast, centrifuge model tests are an alternative for investigating the impact of vibro-installation on the post installation performance of monopiles for different soil conditions. The paper presents the development and first use of a mini vibro-driver in a geotechnical centrifuge. It highlights the importance of performing tests in such a way as to appropriately replicate soil mechanisms during vibro-driving. Finally, results from an initial pile installation test in the centrifuge are presented.