Local Scour Mechanism around Dynamically Active Marine Structures in Noncohesive Sediments and Unidirectional Current
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VIEW THE REPLYPublication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 146, Issue 1
Abstract
This paper sheds light on the mechanism of post equilibrium sea bed scour around dynamically active marine structures such as wind turbines. Exposure of a fully developed scour hole (at equilibrium state) around a wind turbine mono-pile to the cyclic movement of the structure leads to the backfilling and deformation of the scour hole. The existing approaches to scour prediction for foundation design of offshore wind turbines generally consider wind turbines as static structures and ignore the physical impact of the cyclic movement of the pile on the supporting soil and, hence, on the scour process. Through an experimental program, this paper explains the influence of the cyclic movement of the pile on the local scour in noncohesive sediments. A series of flume tests at two scales were conducted. Simple hydrodynamic conditions and bed sediment configurations were adopted to highlight the effect of pile movement. The results obtained indicate that a mechanism exists by which the scour hole can be significantly deeper and wider in extent than that predicted by conventional methods. This arises through a multistage process consisting of periodically alternating cyclically loaded and unloaded stages simulating a sequence of storms.
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Acknowledgments
This study is a part of a Ph.D. project, funded by the Higher Committee for Education Development in Iraq (HCED-Iraq).
References
Adhikari, S., and S. Bhattacharya. 2012. “Dynamic analysis of wind turbine towers on flexible foundations.” Shock Vib. 19 (1): 37–56. https://doi.org/10.3233/SAV-2012-0615.
Baghbadorani, D. A., B. Ataie-Ashtiani, A. Beheshti, M. Hadjzaman, and M. Jamali. 2018. “Prediction of current-induced local scour around complex piers: Review, revisit, and integration.” Coastal Eng. 133 (Mar): 43–58. https://doi.org/10.1016/j.coastaleng.2017.12.006.
Bhattacharya, S., N. Nikitas, J. Garnsey, N. A. Alexander, J. Cox, D. Lombardi, and D. F. Nash. 2013. “Observed dynamic soil–structure interaction in scale testing of offshore wind turbine foundations.” Soil Dyn. Earthquake Eng. 54 (Nov): 47–60. https://doi.org/10.1016/j.soildyn.2013.07.012.
Damgaard, M., M. Bayat, L. V. Andersen, and L. B. Ibsen. 2014. “Assessment of the dynamic behaviour of saturated soil subjected to cyclic loading from offshore monopile wind turbine foundations.” Comput. Geotech. 61 (Sep): 116–126. https://doi.org/10.1016/j.compgeo.2014.05.008.
Damgaard, M., L. B. Ibsen, L. V. Andersen, and J. K. Andersen. 2013. “Cross-wind modal properties of offshore wind turbines identified by full scale testing.” J. Wind Eng. Ind. Aerodyn. 116 (May): 94–108. https://doi.org/10.1016/j.jweia.2013.03.003.
Foglia, A., G. Gottardi, L. Govoni, and L. B. Ibsen. 2015. “Modelling the drained response of bucket foundations for offshore wind turbines under general monotonic and cyclic loading.” Appl. Ocean Res. 52 (Aug): 80–91. https://doi.org/10.1016/j.apor.2015.04.005.
Guan, D., Y.-M. Chiew, B. Melville, and J. Zheng. 2018. “Current-induced scour at monopile foundations subjected to lateral vibrations.” Coastal Eng. 144 (Feb): 15–21. https://doi.org/10.1016/j.coastaleng.2018.10.011.
Harte, M., B. Basu, and S. R. Nielsen. 2012. “Dynamic analysis of wind turbines including soil-structure interaction.” Eng. Struct. 48 (Dec): 509–518. https://doi.org/10.1016/j.engstruct.2012.06.041.
Herrick, J. E., and T. L. Jones. 2002. “A dynamic cone penetrometer for measuring soil penetration resistance.” Soil Sci. Soc. Am. J. 66 (4): 1320–1324. https://doi.org/10.2136/sssaj2002.1320.
Jensen, M. S., B. Juul Larsen, P. Frigaard, L. DeVos, E. D. Christensen, E. Asp Hansen, and S. Bove. 2006. Offshore wind turbines situated in areas with strong currents. Copenhagen, Denmark: Ramboll, Aalborg Univ., Offshore Center Denmark.
Link, O., C. Gobert, M. Manhart, and U. Zanke. 2008. “Effect of the horseshoe vortex system on the geometry of a developing scour hole at a cylinder.” In Proc., 4th Int. Conf. on Scour and Erosion, 162–168. Tokyo: Japanese Geotechnical Society.
Long, J. H., and G. Vanneste. 1994. “Effects of cyclic lateral loads on piles in sand.” J. Geotech. Eng. 120 (1): 225–244. https://doi.org/10.1061/(ASCE)0733-9410(1994)120:1(225).
Matutano, C., V. Negro, J. López-Gutiérrez, and M. D. Esteban. 2013. “Scour prediction and scour protections in offshore wind farms.” Renewable Energy 57 (Sep): 358–365. https://doi.org/10.1016/j.renene.2013.01.048.
Melville, B. W., and S. E. Coleman. 2000. Bridge scour. Highlands Ranch, CO: Water Resources Publication.
Mostböck, A., and Y. Petryna. 2014. “Structural vibration monitoring of wind turbines.” In Proc., 9th Int. Conf. on Structural Dynamics. Porto, Portugal: EURODYN, Faculty of Engineering, Univ. of Porto.
Prendergast, L. J., K. Gavin, and P. Doherty. 2015. “An investigation into the effect of scour on the natural frequency of an offshore wind turbine.” Ocean Eng. 101 (Jun): 1–11. https://doi.org/10.1016/j.oceaneng.2015.04.017.
Sheppard, D. M., B. Melville, and H. Demir. 2011. “Evaluation of existing equations for local scour at bridge piers.” J. Hydraul. Eng. 140 (1): 14–23. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000800.
Soulsby, R. 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. River Edge, NJ: World Scientific.
Sumer, B. M., R. J. Whitehouse, and A. Tørum. 2001. “Scour around coastal structures: A summary of recent research.” Coastal Eng. 44 (2): 153–190. https://doi.org/10.1016/S0378-3839(01)00024-2.
Tavouktsoglou, N. S., J. M. Harris, R. R. Simons, and R. J. S. Whitehouse. 2017. “Equilibrium scour-depth prediction around cylindrical structures.” J. Waterway, Port, Coastal, Ocean Eng. 143 (5): 04017017. https://doi.org/10.1061/(ASCE)WW.1943-5460.0000401.
van der Tempel, J., and D. P. Molenaar. 2002. “Wind turbine structural dynamics—A review of the principles for modern power generation, onshore and offshore.” Wind Eng. 26 (4): 211–222. https://doi.org/10.1260/030952402321039412.
Wang, Z., Y. Zhao, F. Li, and J. Jiang. 2013. “Extreme dynamic responses of mw-level wind turbine tower in the strong typhoon considering wind-rain loads.” Math. Prob. Eng. 2013: 13. https://doi.org/10.1155/2013/512530.
Whitehouse, R. 1998. Scour at marine structures: A manual for practical applications. London: Thomas Telford.
Yu, L., Q. Zhou, and J. Liu. 2015. “Experimental study on the stability of plate anchors in clay under cyclic loading.” Theor. Appl. Mech. Lett. 5 (2): 93–96. https://doi.org/10.1016/j.taml.2015.02.005.
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©2019 American Society of Civil Engineers.
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Received: Feb 2, 2018
Accepted: Mar 26, 2019
Published online: Oct 1, 2019
Published in print: Jan 1, 2020
Discussion open until: Mar 1, 2020
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