3D FEM analysis of scour protection effect on monopile-soil interaction

Offshore wind energy represents a fundamental, yet continuously evolving, resource for the global energy transition. At present, monopile foundations constitute the most widespread structural solution for supporting wind turbines. One of the primary issues associated with these structures is the phenomenon of local seabed erosion, also known as scour, which can compromise the stability and stiffness of the system. To mitigate this risk, rock armour protection solutions are typically installed. The present thesis work aims to thoroughly investigate the impact of scour protection on the soil-structure interaction of the monopile, analysing not only its well-known function as a hydraulic barrier, but also quantitatively evaluating its contribution as an actual geotechnical reinforcement element. The investigation was conducted through three-dimensional Finite Element numerical modelling using the PLAXIS 3D software. A parametric study was developed to assess the mechanical response of the system by varying the geometry of the protection and the stratigraphic conditions of the installation site. Concurrently, the research addressed a significant topic related to numerical modelling strategies, comparing the use of continuous volumetric elements, as soil volume element, with the application of an equivalent surface load.