Incipient Motion of Riprap on Steep Slopes
Publication: Journal of Hydraulic Engineering
Volume 141, Issue 9
Abstract
Liu’s theory of 1957 to estimate the point of incipient motion, derived assuming a flat bed slope and uniform flow, states that for large particles the movability number (defined as the ratio of the shear velocity to the settling velocity), is constant. Data collected from 12 undistorted and unscaled laboratory tests was used to investigate the applicability of the theory on steep riprap slopes. The tests indicate that the dimensionless movability number (MN) is constant for large particle Reynold numbers. For design purposes, the recommended movability number which emerged from this study is 0.18, provided that the steep bed slope is taken into account, the energy slope is considered in MN, and that the theoretical settling velocity is calculated using an accurate drag coefficient and the sieve size of the riprap.
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References
Abt, S., and Johnson, T. L. (1991). “Riprap design for overtopping flow.” J. Hydraul. Eng., 959–972.
Annandale, G. W. (2006). Scour technology: Mechanics and engineering practice, McGraw-Hill, New York.
Armitage, N. P. (2002). “A unit stream power model for the prediction of local scour in rivers.” Doctoral dissertation, Univ. of Stellenbosch, Stellenbosch, South Africa.
Armitage, N. P., and Rooseboom, A. (2010). “The link between movability number and incipient motion in river sediments.” Water SA, 36(1), 89–96.
CIRIA, CUR, and CETMEF. (2007). The rock manual: The use of rock in hydraulic engineering, 2nd Ed., CIRIA, London.
Concha, F. (2009). “Settling velocities of particulate systems.” KONA Powder Part. J., 27, 18–37.
Dey, S., Sarker, H. K. D., and Debnath, K. (1999). “Sediment threshold on stream-wise bed slopes.” Proc., 26th National Conf. on Fluid Mechanics and Fluid Power, Indian Institute of Technology, Kharagpur, 255–262.
Garde, R. J., and Raju, K. G. R. (2000). Mechanics of sediment transportation and alluvial stream problems, New Age International Publishers, New Delhi, India.
Liu, H. K. (1957). “Mechanics of sediment-ripple formation.” J. Hydraul. Div., 83(2), 1–23.
Maynord, S. T., Ruff, J., and Abt, S. (1989). “Riprap design.” J. Hydraul. Eng., 937–949.
Przedwojski, B., Blazejewski, R., and Pilarczyk, K. W. (1995). River training techniques: fundamentals, design and applications, Balkema Publishers, Rotterdam, Netherlands.
Robinson, K. M., Rice, C., and Kadavy, K. C. (1998). “Design of rock chutes.” Am. Soc. Agric. Eng., 41(3), 621–626.
Rooseboom, A. (1992). “Sediment transport in rivers and reservoirs: A southern African perspective.”, Water Research Commission.
SANRAL (The South African National Road Agency). (2013). Drainage manual, 6th Ed., Pretoria, South Africa.
Shields, A. (1936). “Application of similarity mechanics and turbulence research on stream flow.” Mitteilungen der Preussischen Versuchsanstalt für Wasserbau und Schiffbau, Berlin, Germany.
Simons, D. B., and Sentürk, F. (1992). Sediment transport technology: Water and sediment dynamics, 2nd Ed., Water Resources Publications, Littleton, CO.
Stoffberg, F. W. (2005). “Evaluation of incipient motion criteria for rocks in reno mattresses and rip rap.” M.Sc. thesis, Univ. of Stellenbosch, Stellenbosch, South Africa.
van der Walt, S. C. (2005). “Mathematical modelling of sediment transport dynamics in the Berg river considering current and future water resources development scenarios.” M.Sc. thesis, Univ. of Stellenbosch, Stellenbosch, South Africa.
Whitehouse, R., and Hardisty, J. (1988). “Experimental assessment of two theories for the effect of bed slope on the threshold of bed-load transport.” Mar. Geol., 79(1–2), 135–139.
Wu, W., Wang, S., and Jia, J. (2000). “Nonuniform sediment transport in alluvial rivers.” J. Hydraul. Res., 38(6), 427–434.
Yang, C. T. (1973). “Incipient motion and sediment transport.” J. Hydraul. Div., 99(10), 1679–1704.
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Published In
Journal of Hydraulic Engineering
Volume 141 • Issue 9 • September 2015
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Nov 22, 2013
Accepted: Feb 4, 2015
Published online: May 12, 2015
Published in print: Sep 1, 2015
Discussion open until: Oct 12, 2015
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