DOI QR코드

DOI QR Code

Experimental Analysis for Characteristics of Bank-Scour around Barrier

수리실험을 통한 보 연결부 제방 세굴 특성 분석

  • Received : 2016.10.10
  • Accepted : 2017.07.28
  • Published : 2017.08.31

Abstract

Typical flow regime of overflow at barrier or weir constructed in mid and small streams becomes as the submerged flow during most flood events. One of major causes of barrier failure has been reported as the levee-scour near the conjuction node between barrier and levee. However, most related design guidelines in Korea have not mentioned about the protection of levee around barrier or weir in detail. Furthermore, most previous researches have focused on the flow characteristics of overflow around several types of weirs but they did not have considered the material properties of levee itself. In this study, local scour near barrier was investigated with different material properties of levee under the submerged overflow condition which is assumed to reenact a flood event. Based on results from Fritz et al. and Mavis et al., a theoretical formula was also proposed in initial stage of laboratory experiments. And hydraulic experiments were carried out for the verification of the proposed formula. Levee was installed in the prismetic trapezoidal open channel and most parts were made of concrete except for movable section in which scour was expected to occur for the efficiency of experimental procedure. Each compaction of movable section in levee was followed by the basis of the KS F 2312. Further, after performing the experiments to find the optimum water content for each sediment, the specific amount of water was injected before flowing water. The difference between the proposed theoretical formula and experiment results was not much but considerable, which might be caused by the effect of compaction. For theoretical approach, it seemed that the formula did not take into account the compaction of levee, thus the correction coefficient for levee compaction determined in the literature was considered. Finally, the formula for the length of scour around barrier or weir was proposed, which can be useful to predict a levee in the reference design of revetment in mid and small streams. As shortly future study, scour length of levee around barrier or weir under different flow conditions such as perfect overflow condition will be studied and it will be able to contribute to suggest the design formula or criteria under all overflow conditions near barrier or weir.

Keywords

References

  1. Korea Institute of Construction Technology, "Development of Design Techniques for Barrier and Drop Structures", KAIA, 2006.
  2. Korean Water Resources Associations, River Dsign Sandard, 2009.
  3. M. Escarameia, May, R.W.P, Channel Protection-T urbulence Downstream of Structures, Report SR 313, HR Wallingford, 1992.
  4. K. W. Pilarczyk, "Stability Criteria for Revetments", Hydraulic Engineering, Proceedings of the 1990 National Conference. American Society of Civil Engineers, New York, pp. 245-250, 1990.
  5. S. T. Maynord, "Corps Riprap Design Guidance for Channel Protection", River, Coastal and Shoreline Protection: Erosion Control using Riprap and Armour Stone, pp. 41-52, 1993.
  6. H. M. Fritz and W. H. Hager, "Hydraulics of Embankment Weirs", Journal of Hydraulic Engineering, Vol. 124, Issue 9, pp. 963-971, 1998. https://doi.org/10.1061/(ASCE)0733-9429(1998)124:9(963)
  7. F. T. Mavis and L. Laushey, "Formula for Velocity at Beginning of Bed-Load Movement is Appraised", Civil Engineering, ASCE, Vol. 19, Issue 1, pp. 38-39, 1949.
  8. J. T. Lee and S. T. Lee, "An Experimental Study on the Collapse Phase of a River Leeves (II) -Effect of the Soil Properties and Compactness", Journal of Korea Water Resources Association, Vol. 34, Issue 2, pp.141-154, 2001.