Influence of a jack-up installation near a wind turbine foundation: a numerical study

Jack-up vessels are often used for the installation of wind turbines or their foundations. During the operational phase, restrictions on the vessel layout may cause delays during installation. Ideally, the jack-up is placed as close as possible to the foundation to facilitate the transport of the different wind turbine components. However, placing a jack-up too close to a foundation may cause problems on the foundation stiffness, which originally is not designed to support either the additional loading caused by a spud- can, or the footprint left after installation. This article describes how to apply the finite element method to define when the distance between jack-up and structure and foundation do not affect the foundation stiffness. If the available distance is not sufficient, the finite element method can also be used to estimate the influence of the spudcan extraction on possible soil stiffness degradation. The paper confirms the recommended clearance according to ABS (2018) and SNAME (2008) and presents an example of soil degradation due jack-up installation of less distance.