Decommissioning of subsea structures founded on shallow foundations currently requires the complete re-moval of the structure, but there are challenges in predicting the associated recovery loads. This work exam-ines the extraction behaviour of shallow, skirted, square foundations in soft clay by means of a series of dis-placement-controlled small scale model tests. Skirt length, uplift rate, surface drainage condition and pre-load were all varied. Extraction behaviour is seen to be different depending on whether the foundation re-tains a soil plug which in turn seems to depend on the kinematics rather than rate effects. Prediction of re-covery loads based on assuming plugged behaviour in all cases provided an upper bound without excessive conservatism. Prediction of recovery loads based on model preload was only successful under certain condi-tions, and thus should be considered as an estimate only.
|Title of host publication||Offshore Site Investigation and Geotechnics: Smarter Solutions for Future Offshore Developments|
|Subtitle of host publication||Proceedings of the 8th International Conference, held 12–14 September 2017 at the Royal Geographical Society, London|
|Publisher||Society for Underwater Technology|
|ISBN (Print)||9780906940570 (hbk) Volume 1, 9780906940587 (hbk) Volume 2|
|Publication status||Published - 12 Sep 2017|
|Event||8th Offshore Site Investigation and Geotechnics International Conference: ‘Smarter Solutions for Future Offshore Developments’ - Royal Geographical Society, London, United Kingdom|
Duration: 12 Sep 2017 → 14 Sep 2017
http://www.sutconnects.com/ (Link to conference website)
|Conference||8th Offshore Site Investigation and Geotechnics International Conference|
|Period||12/09/17 → 14/09/17|
- Skirted foundations
Brennan, A., Brown, M., Knappett, J., McMillan, C., Aldaikh, H., Small, A. A., & Morrow, D. (2017). Model Testing of Recovery Loads for Decommissioning Skirted Subsea Structures. In Offshore Site Investigation and Geotechnics: Smarter Solutions for Future Offshore Developments: Proceedings of the 8th International Conference, held 12–14 September 2017 at the Royal Geographical Society, London (Vol. 1-2, pp. 749-756). Society for Underwater Technology.