Abstract
Carrying out a hazard assessment for offshore structures can entail the consideration of a number of different factors. Scour hazard assessments are routinely undertaken, and scour development at offshore structures should be considered a time-varying process. However, scour may take place within a morphologically dynamic environment, the combination of which will impact on the soil–structure–fluid response. This paper presents the analysis of an unique data set that shows the partial collapse of a scour hole at a large monopile foundation within a morphologically active site. The collapse suggests a slope failure mechanism, resulting in the movement of around 450 m3 of material within a period of about 75 min. The paper analyzes the processes involved regarding formation and development of the collapse.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This research was funded by HR Wallingford's scour research program and was partly undertaken while the lead author was a Visiting Research Fellow in the School of Civil, Environmental and Mining Engineering within the Faculty of Engineering, Computing and Mathematics at the University of Western Australia.
References
Al-Hammadi, M., and R. R. Simons. 2016. “Effect of vibration on the scour process around cylindrical structures under unidirectional flow in a sandy bed.” In Proc., 8th Int. Conf. on Scour and Erosion, edited by J. Harris, R. Whitehouse, and S. Moxon, 157–161. Boca Raton, FL: CRC Press.
Baykal, C., B. M. Sumer, D. R. Fuhrman, N. G. Jacobsen, and J. Fredsøe. 2015. “Numerical investigation of flow and scour around a vertical circular cylinder.” Philos. Trans. A Maths Phys. Eng. Sci. 373 (2033): 20140104. https://doi.org/10.1098/rsta.2014.0104.
Breusers, H. N. C. 1974. “Suction of sand.” Bull. Int. Assoc. Eng. Geol. 10 (1): 65–66. https://doi.org/10.1007/BF02634636.
Breusers, H. N. C., and A. J. Raudkivi. 1991. Scouring. Vol. 2 of IAHR hydraulic structures design manual series. Rotterdam, Netherlands: A. A. Balkema.
Chu, J., M. G. Ho, W. L. Loke, and W. K. Leong. 2004. “Effects of scour and hydraulic gradient on the stability of granular soil slope.” In Vol. 2 of Proc., 2nd Int. Conf. on Scour and Erosion, 439–452. Singapore: Nanyang Technological University.
Hampton, M. A., H. J. Lee, and J. Locat. 1996. “Submarine landslides.” Rev. Geophys. 34 (1): 33–59. https://doi.org/10.1029/95RG03287.
Harris, J. M., R. J. S. Whitehouse, and T. Benson. 2010. “The time evolution of scour around off-shore structures.” Proc. Inst. Civ. Eng. Marit. Eng. 163 (1): 3–17.
Mastbergen, D., G. van den Ham, M. Cartigny, A. Koelewijn, M. de Kleine, M. Clare, J. Hizzett, M. Azpiroz, and A. Vellinga. 2016. “Multiple flow slide experiment in the Westerschelde Estuary, The Netherlands.” In Vol. 41 of Advances in natural and technological hazards research, edited by G. Lamarche et al., 241–249. Cham, Switzerland: Springer.
Melville, B. W., and S. E. Coleman. 2000. Bridge scour. Littleton, CO: Water Resources Publications, LLC.
Petersen, T. U. 2014. “Scour around offshore wind turbine foundations.” Ph.D. thesis, Section for Fluid Mechanics, Coastal and Maritime Engineering, Dept. of Mechanical Engineering, Technical Univ. of Denmark.
Petersen, T. U., B. M. Sumer, J. Fredsøe, T. Raaijmakers, and J. Schouten. 2015. “Edge scour at scour protection around piles in the marine environment—Laboratory and field investigation.” Coastal Eng. 106: 42–72.
Reese, L. C., S. T. Wang, and J. H. Long. 1989. “Scour from cyclic lateral loading of piles.” In Vol. 2 of Proc., 21st Offshore Technology Conf., 395–402. Houston: Offshore Technology Conference.
Robertson, P. K. 2010. “Evaluation of flow liquefaction and liquefied strength using the cone penetration test.” J. Geotech. Geoenviron. Eng. 136 (6): 842–853. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000286.
Soulsby, R. L. 1997. Dynamics of marine sands: A manual for practical applications. London: Thomas Telford.
Sumer, B. M., and J. Fredsøe. 2002. The mechanics of scour in the marine environment. Vol. 17 of Advanced series on ocean engineering. Singapore: World Scientific.
Sumer, B. M., T. U. Petersen, L. Locatelli, J. Fredsøe, R. E. Musumeci, and E. Foti. 2013. “Backfilling of a scour hole around a pile in waves and current.” J. Waterway, Port, Coastal, Ocean Eng. 139 (1): 9–23. https://doi.org/10.1061/(ASCE)WW.1943-5460.0000161.
Terzaghi, K. 1957. Varieties of submarine slope failures. Norwegian Geotechnical Institute, Publication No. 25, 1–16. Cambridge, MA: Harvard University.
van Rhee, C. 2015. “Slope failure by unstable breaching.” Proc. Inst. Civ. Eng. Marit. Eng. 168 (2): 84–92. https://doi.org/10.1680/jmaen.14.00006.
van Rhee, C., and A. Bezuijen. 1998. “The breaching of sand investigated in large-scale model tests.” In Vol. 3 of Proc., 26th Int. Conf. on Coastal Engineering, edited by B. L. Edge, 2509–2519. Reston, VA: ASCE.
Whitehouse, R. J. S. 1998. Scour at marine structures: A manual for practical applications. London: Thomas Telford.
Information & Authors
Information
Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 145 • Issue 6 • November 2019
Copyright
© 2019 American Society of Civil Engineers.
History
Received: Oct 2, 2018
Accepted: Feb 1, 2019
Published online: Sep 3, 2019
Published in print: Nov 1, 2019
Discussion open until: Feb 3, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.