Experimental Study for the Determination of the Material Diameter of the Riprap Bed Protection
- 1
- 2
- 3
- 4
Abstract
Bed protection in apron downstream was installed to use riprap or gabion mattress. In the case of bed protection using riprap, the decision on the riprap diameter is very important because riprap diameter means the capacity to withstand the flow. Initial formulas for the decision on the riprap diameter applied velocity and weight as main factors. Since the main factors gradually expanded to depth, bed slope, and turbulence intensity, decision formulas for the riprap diameter were detailed. Because turbulence intensity was considered to be a main factor of the formula, the decision formulas for the riprap diameter could be expanded to apply to bed protection around hydraulic structures. Escarameia and May conducted a study on the riprap diameter of a strong turbulence area around the downstream of hydraulic structures. For the formula of Escarameia and May, the basis of the formula was the Izbash type, and the main factor was turbulence intensity. This study was an experimental study for deciding the riprap diameter installed around apron downstream and was based on the study results of Escarameia and May. The experiment measured the velocity upon change of discharge and riprap diameter to the installed weir model and analyzed the correlation of threshold velocity by diameter. The experimental formula in this study expanded the turbulence intensity limits of the Escarameia and May formula and increased application to turbulence intensity in weir downstream.
- Korea Water Resources Association, “River Design Criteria,” 2004.
- D. Bijan, “Scour Development Downstream of a Spillway,” Journal of Hydraulic Research, Vol. 41, No. 4, 2003, pp. 417-426. doi:10.1080/00221680309499986
- W. C. Little and J. B. Murphy, “Model Study of Low Drop Grade control Structures,” Journal of Hydraulic Division, Vol. 108, No. 10, 1982, pp. 1132-1146.
- M. Escarameia and R. W. P. May, “Channel Protection; Turbulence Downstream of Structures,” HR Report SR 313, 1992.
- J. C. Blodgett and C. E. McConaughy, “Rock Riprap Design for Protection of Stream Channels Near Highway Structures. Vol. 2, Evaluation of Rip-rap Design Procedures,” Water Resources Investigations Report, U.S. Geological Survey, Sacramento, 1986.
- W. C. Little and J. B. Murphy, “Model Study of Low Drop Grade control Structures,” Journal of Hydraulic Division, Vol. 108, No. 10, 1982, pp. 1132-1146.
- Korea Institute of Con-struction Technology, “The Multi-Function River Design Criteria,” 2004.
- CIRIA, “Manual on Scour at Bridges and Other Hydraulic Structures,” 2002.
- CUR/RWS, “Manual on the Use of Rock in Hydraulic Engineering,” CUR Report 169, Centre for Civil Engineering Research and Codes (CUR), A.A. Balkema, 1995.