Interactions in offshore foundation design

Journal article

This paper presents some examples of design problems for offshore foundations, drawn from the jack-up industry and the wind turbine industry. The examples are chosen to illustrate some general points about foundation design, geotechnical engineering and its interaction with other disciplines. The first example is drawn from the assessment of the safety of installation of jack-up units (large mobile offshore drilling rigs). It illustrates how more rational approaches can be achieved through a deeper use of probabilistic methods in both the prediction of performance and the assessment of field observations. The second example also comes from jack-up practice, but has wider application too: it addresses the classical problem of the performance of foundations under combined loading, and how this can be understood in a simple theoretical and practical framework based on plasticity theory. The final example comes from the renewables sector, where the rapidly expanding offshore wind industry poses new foundation challenges for geotechnical engineers. Practical and economic foundation solutions are required if the UK is to meet its ambitious plans to exploit larger turbines in deeper waters. Both conventional (monopile) and novel solutions (suction caissons, screw piles) to the foundation problem are discussed. The paper also demonstrates how interactions with other disciplines can enrich geotechnical engineering, illustrated by specific practical examples from the author's experience.

Authors: Houlsby, G

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Thomas Telford
• Journal: Géotechnique
• Volume: 66
• Issue: 10
• Pages: 791-825
• Publication date: 2016-08-17
• Acceptance date: 2016-04-26
• DOI: 10.1680/jgeot.15.RL.001
• EISSN: 1751-7656
• ISSN: 0016-8505
• Keywords: plasticity; model tests; sands; statistical analysis; footings/foundations; piles and piling; clays; soil/structure interaction; offshore engineering