Abstract
Colocated sediment pore pressures at depths of approximately 0.02 and 0.22 m below the sand surface and near-bed water velocities were measured for approximately 2 weeks in approximately 1 m mean water depth on an ocean beach near Duck, North Carolina. These measurements suggest that storm wave-driven liquefaction processes may enhance local shoreward sediment transport. During the passage of tropical storm Melissa, wave heights in 26-m water depth (NDBC 44100) were 1–4 m, and storm surge (approximately 1 m) and wave-induced setup increased the water depth on the beach. Upward vertical gradients in pressure heads between the sensors increased with the storm approach, with the largest values observed before the maxima in local wave heights, wave periods, and water depths. The large gradients in pore pressure exceeded several liquefaction criteria and usually occurred when near-bed velocities were upward- and shoreward-directed.
Practical Applications
Observations on an ocean beach show that during storms the water pressure below the sand surface can be greater than the pressure near the sand surface. When that difference in pressure (called a pressure gradient) becomes large, the sediments fluidize, that is, they act like a fluid in a process called liquefaction. Unlike dry or partially wet sediments, the fluidized sand is moved easily by currents. During tropical storm Melissa, large upward-directed pressure gradients fluidized the sediment, usually as the crest of an ocean wave passed over the surface. Therefore, the sediments possibly became free to move as a liquid when the currents from waves were directed both upward and toward the shore. The liquified sediments could be transported shoreward, leading to changes to the sand surface (accretion and erosion). This phenomenon is important to understand because it contributes to how, where, and when sediment might be transported on an ocean beach.
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Acknowledgments
We thank the staff of the U.S. Army Engineer Research and Development Center Field Research Facility, Levi Gorrell for providing logistical and field support, and Brittany Bruder for providing and assisting with the sea state images. We thank the U.S. Coastal Research Program (USCRP) for its coordination and facilitation of the During Nearshore Event Experiment (DUNEX). Research funding was provided by the National Science Foundation (awards CMMI-1751463, OCE-1829136, OCE-1848650, and OCE-1933010), the USCRP, and a Vannevar Bush Faculty Fellowship. The authors declare no financial or other conflicts of interest.
References
Amoudry, L. O., and A. J. Souza. 2011. “Deterministic coastal morphological and sediment transport modeling: A review and discussion.” Rev. Geophys. 49 (2): 1–21. https://doi.org/10.1029/2010RG000341.
Briganti, R., A. Torres-Freyermuth, T. E. Baldock, M. Brocchini, N. Dodd, T. J. Hsu, J. Zhonglian, K. Yeulwoo, J. C. Pintado-Patino, and M. Postacchini. 2016. “Advances in numerical modelling of swash zone dynamics.” Coastal Eng. 115: 26–41. https://doi.org/10.1016/j.coastaleng.2016.05.001.
Butt, T., P. Russell, and I. Turner. 2001. “The influence of swash infiltration–exfiltration on beach face sediment transport: Onshore or offshore?” Coastal Eng. 42 (1): 35–52. https://doi.org/10.1016/S0378-3839(00)00046-6.
Carrier, W. D., III 2003. “Goodbye, Hazen; Hello, Kozeny–Carman.” J. Geotech. Geoenviron. Eng. 129 (11): 1054–1056. https://doi.org/10.1061/(ASCE)1090-0241(2003)129:11(1054).
Chardón-Maldonado, P., J. C. Pintado-Patiño, and J. A. Puleo. 2016. “Advances in swash-zone research: Small-scale hydrodynamic and sediment transport processes.” Coastal Eng. 115: 8–25. https://doi.org/10.1016/j.coastaleng.2015.10.008.
Conley, D. C., and D. L. Inman. 1994. “Ventilated oscillatory boundary layers.” J. Fluid Mech. 273: 261–284. https://doi.org/10.1017/S002211209400193X.
Duncan, J. M., B. O’Neil, T. Brandon, and D. R. VandenBerge. 2011. Vol. 64 of Evaluation of potential for erosion in levees and levee foundations, 1–40. Blacksburg, VA: Center for Geotechnical Practice and Research.
Elfrink, B., and T. Baldock. 2002. “Hydrodynamics and sediment transport in the swash zone: A review and perspectives.” Coastal Eng. 45 (3–4): 149–167. https://doi.org/10.1016/S0378-3839(02)00032-7.
Elgar, S., and R. T. Guza. 1985. “Observations of bispectra of shoaling surface gravity waves.” J. Fluid Mech. 161: 425–448. https://doi.org/10.1017/S0022112085003007.
Elgar, S., B. Raubenheimer, and R. T. Guza. 2005. “Quality control of acoustic Doppler velocimeter data in the surfzone.” Meas. Sci. Technol. 16 (10): 1889. https://doi.org/10.1088/0957-0233/16/10/002.
Guest, T. B., and A. E. Hay. 2017. “Vertical structure of pore pressure under surface gravity waves on a steep, megatidal, mixed sand-gravel-cobble beach.” J. Geophys. Res.: Oceans 122 (1): 153–170. https://doi.org/10.1002/2016JC012257.
Guo, Z., D.-S. Jeng, H. Zhao, W. Guo, and L. Wang. 2019. “Effect of seepage flow on sediment incipient motion around a free spanning pipeline.” Coastal Eng. 143: 50–62. https://doi.org/10.1016/j.coastaleng.2018.10.012.
Heathershaw, A. D., A. P. Carr, M. W. L. Blackley, and C. F. Wooldridge. 1981. “Tidal variations in the compaction of beach sediments.” Mar. Geol. 41: 223–238. https://doi.org/10.1016/0025-3227(81)90082-7.
Horn, D. 2002. “Beach groundwater dynamics.” Geomorphology 48: 121–146. https://doi.org/10.1016/S0169-555X(02)00178-2.
Kirchner, J. W., W. E. Dietrich, F. Iseya, and H. Ikeda. 1990. “The variability of critical shear stress, friction angle, and grain protrusion in water-worked sediments.” Sedimentology 37: 647–672. https://doi.org/10.1111/j.1365-3091.1990.tb00627.x.
Madsen, O. S. 1974. “Stability of a sand bed under breaking waves.” Coastal Eng. Proc. 1 (14): 45. https://doi.org/10.9753/icce.v14.45.
Mei, C. C., and M. A. Foda. 1981. “Wave-induced responses in a fluid-filled poroelastic solid with a free surface: A boundary layer theory.” Geophys. J. Int. 66 (3): 597–631. https://doi.org/10.1111/j.1365-246X.1981.tb04892.x.
Mory, M., H. Michallet, D. Bonjean, I. Piedra-Cueva, J. M. Barnoud, P. Foray, S. Abadie, and P. Breul. 2007. “A field study of momentary liquefaction caused by waves around a coastal structure.” J. Waterway, Port, Coastal, Ocean Eng. 133 (1): 28–38. https://doi.org/10.1061/(ASCE)0733-950X(2007)133:1(28).
Packwood, A. R., and D. H. Peregrine. 1979. “The propagation of solitary waves and bores over a porous bed.” Coastal Eng. 3: 221–242. https://doi.org/10.1016/0378-3839(79)90022-X.
Pujara, N., P. L.-F. Liu, and H. H. Yeh. 2015. “An experimental study of the interaction of two successive solitary waves in the swash: A strongly interacting case and a weakly interacting case.” Coastal Eng. 105: 66–74. https://doi.org/10.1016/j.coastaleng.2015.07.011.
Raubenheimer, B., S. Elgar, and R. Guza. 1998. “Estimating wave heights from pressure measured in sand bed.” J. Waterway, Port, Coastal, Ocean Eng. 124 (3): 151–154. https://doi.org/10.1061/(ASCE)0733-950X(1998)124:3(151).
Sakai, T., K. Hatanaka, and H. Mase. 1992. “Wave-induced effective stress in seabed and its momentary liquefaction.” J. Waterway, Port, Coastal, Ocean Eng. 118 (2): 202–206. https://doi.org/10.1061/(ASCE)0733-950X(1992)118:2(202).
Seymour, R. 2013. Nearshore sediment transport. 1st ed. New York: Springer.
Sleath, J. F. A. 1999. “Conditions for plug formation in oscillatory flow.” Cont. Shelf Res. 19: 1643–1664. https://doi.org/10.1016/S0278-4343(98)00096-X.
Stark, N., P. Mewis, B. Reeve, M. Florence, J. Piller, and J. Simon. 2022. “Vertical pore pressure variations and geotechnical sediment properties at a sandy beach.” Coastal Eng. 172: 104058. https://doi.org/10.1016/j.coastaleng.2021.104058.
Sumer, M. 2014. Liquefaction around marine structures. 1st ed. Singapore: World Scientific.
Terzaghi, K. 1943. Theoretical soil mechanics. New York: Wiley.
Turner, I. L., and G. Masselink. 1998. “Swash infiltration–exfiltration and sediment transport.” J. Geophys. Res.: Oceans 103 (C13): 30813–30824. https://doi.org/10.1029/98JC02606.
Yamamoto, T., H. L. Koning, H. Sellmeijer, and E. van Hijum. 1978. “On the response of a poro-elastic bed to water waves.” J. Fluid Mech. 87 (1): 193–206. https://doi.org/10.1017/S0022112078003006.
Yeh, H., and H. B. Mason. 2014. “Sediment response to tsunami loading: Mechanisms and estimates.” Géotechnique 64 (2): 131–143. https://doi.org/10.1680/geot.13.P.033.
Zhai, H., D.-S. Jeng, Z. Guo, and Z. Liang. 2021. “Impact of two-dimensional seepage flow on sediment incipient motion under waves.” Appl. Ocean Res. 108: 102510. https://doi.org/10.1016/j.apor.2020.102510.
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Received: Jan 13, 2022
Accepted: Jun 12, 2022
Published online: Sep 14, 2022
Published in print: Nov 1, 2022
Discussion open until: Feb 14, 2023
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