A unified modelling framework for vibratory pile driving methods

The ambitious goals towards the decarbonization of the global energy sector have amplified the demand for renewable energy resources. Amongst the renewables, offshore wind possesses a pivotal role in this endeavour, showcasing remarkable growth in recent years. However, this rapid expansion has been accompanied by a series of technical challenges. Foundation installation comprises one of the most critical phases in the construction of an offshore wind farm and engineering advancements in this topic are vital to accommodate this developmental pace. Bottom-fixed foundations are primarily used to support offshore wind turbines and amongst the available concepts, the monopile is the foremost one. The installation of these substructures is most commonly performed via impact hammering. Notwithstanding the robustness and efficacy of this technique, major environmental concerns have been raised due to the significant levels of underwater noise pollution during driving. In view of this alarming issue, alternative and sustainable pile installation techniques have been progressively drawing attention during the last decade and an increasing number of research projects focus on their investigation and development.

At present, the offshore wind industry is increasingly adopting vibratory pile driving. The previous method has been successfully employed in onshore projects for decades, albeit its wider use in the offshore environment is hindered due to the incompleteness of available field observations. To boost the improvement of vibratory installation methods, a new technology has been recently proposed by the Delft University of Technology, namely the Gentle Driving of Piles (GDP). The preceding method aims to enhance the installation performance of vibratory driving for tubular (mono)piles and to reduce the associated noise emissions, via the simultaneous application of low-frequency/axial and high-frequency/torsional vibrations. Naturally, the shift to these technologies is accompanied by emerging research questions pertaining to pile installation, vibro-acoustic and post-installation performances. In this thesis, the development of an engineering-oriented modelling framework for axial vibratory driving and GDP is the primary objective, thereby focusing on the topic of sustainable monopile installation.