Worldwide and in Europe, there is a huge expansion of offshore wind, however to date little thought has been given to “what happens when we no longer need the foundations?”. Hollow steel piles (monopiles) are generally the foundation type of choice for offshore renewable energy in relatively shallow water.
Their future cost-effective full removal has clear benefits and is an obvious focal point for research at present. The removal of piles can fall into two classifications i.e. “self-removal”, and removal by axial pull using standard craneage, where in the latter case significant reduction of extraction loads is required to make this a practical proposition. The term “self-removal” refers to the use of the foundation system itself without the need for heavy lifting equipment (over and above that associated with lifting the self-weight of the foundation). Three techniques appear viable under this classification: overpressure, vibration and rotation [1,2]. None of these techniques have yet to be studied in detail at the scale of a typical offshore monopile.
The project aim is to develop computational models of these removal processes, to understand their effectiveness in different soil conditions and enable prototype and full scale take up to be developed. It will allow cost-effective parametric analysis and virtual prototyping prior to expensive demonstration and risk adverse deployment. The nature of the study through computational techniques allows not only the extraction method to be optimised but also the geometry of the piles for future designs to aid extraction whilst maintaining in-service requirements. One key objective will be validation against physical modelling and field data.
For the PhD student, the scientific novelty will comprise: development of new computational techniques of much wider applicability to problems in civil and mechanical engineering; the first parametric study of monopile removal techniques and the derivation of initial guidelines for removal methods for industry.
This PhD scholarship is offered by the Aura Centre for Doctoral Training in Offshore Wind Energy and the Environment; a partnership between the Universities of Durham, Hull, Newcastle and Sheffield. The successful applicant will undertake a PG-Dip training year at the University of Hull before completing their PhD research at Durham University.
For more information visit www.auracdt.hull.ac.uk. Or if you have a direct question about the project, please email [Email Address Removed] and we will forward the query to the relevant supervisor. Please do not contact the project supervisors directly.
The Supervisors are:
Prof Charles Augarde, University of Durham
Prof Will Coombs, University of Durham
Entry requirements
If you have received a First-class Honours degree or a 2:1 Honours degree and a Masters (or the international equivalents) in Engineering, Earth Science, Mathematics, Physics, with an interest in computational methods, we would like to hear from you.
Applications are made via an online form. Visit the Aura CDT website for more information:
https://auracdt.hull.ac.uk/innovative-decommissioning-for-offshore-foundation-systems/
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