Set-up effects of dynamically installed anchors

To reduce the cost of mooring for floating offshore wind turbines, the so-called Dynamically Installed Anchor can be a viable solution. However, to use this anchor on a large scale for floating wind farms, a better understanding of the soil state after installation is needed to reliably predict the performance under in-situ conditions. For that purpose, fully coupled stress-equilibrium and pore pressure dissipation finite element analyses were performed. The anchor penetration was simulated with a prescribed penetration rate and the stress state and pore pressure field was calculated using a rate-dependent effective-stress-based constitutive soil model. Full pore pressure dissipation was allowed after reaching the final penetration depth. A considerable stress setup could be observed, despite a small permanent reduction in effective tangential stresses at a distance of approximately three diameters from the anchor. The result from this study provides guidance on defining an appropriate soil strength profile for the in-place design.