Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
권호 표지
DOI QR코드

DOI QR Code

Experimental analysis of the sedimentation processes by variation of standing angle in the improved-pneumatic-movable weir

실내실험에 의한 가동보 기립각도 변화에 대한 토사의 퇴적 과정 분석

  • Lee, Kyung Su (National Disaster Management Institute, Ministry of the Interior and Safety) ;
  • Jang, Chang-Lae (Department of Civil Engineering, Korea National University of Transportation)
  • 이경수 (행정안전부 국립재난안전연구원) ;
  • 장창래 (한국교통대학교 토목공학과)
  • Received : 2018.06.06
  • Accepted : 2018.07.30
  • Published : 2018.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

This study investigates the hydraulic characteristics and the delta development processes in the improved-pneumatic-movable weir by considering the standing angle of the weir through laboratory experiments. The delta migration speed decreases rapidly with time. As the ratio of delta height to water depth increases, the dimensionless delta migration speed decreases at the delta point. Therefore, the water depth decreases as the delta height increases. Although the delta volume is large due to the effective height of the delta, the delta migration speed and sediment deposition decreases because of the backwater effect on the delta. On the same bed slope condition, the larger the weir height, the larger the delta volume and the ratio of delta height to delta front length is close to 1.0. The delta development could be suppressed when the weir is high. Therefore, the condition that the weir is high has the suppressing effect on the delta developments.

본 연구에서는 실내실험을 통하여 개량형 공압식 가동보를 대상으로 보의 기립각도를 고려한 유사의 퇴적과 델타의 발달 과정을 파악하였다. 가동보 상류에서 유입되는 유사는 배수의 영향으로 유속이 느려지면서 퇴적이 되고 델타가 형성되며 하류로 이동하였다. 각 실험조건에 대하여 시간에 따른 델타의 이동속도는 델타는 시간이 지나면서 현저하게 감소하고, 보에 접근하였다. 무차원 델타의 높이($h_d/h$)가 증가할수록 무차원 델타의 이동속도($S_D/V_0$)는 감소하였다. 따라서 델타의 높이($h_d$)가 증가할수록 수심(h)은 감소하였다. 델타의 유효높이($h_w$)가 크기 때문에 델타의 체적($V_{xD}$)은 증가하지만 배수(backwater)의 영향을 받아 델타의 이동속도($S_D$)와 퇴적량은 감소하였다. 수로 경사가 일정할 때, 보의 높이(W)가 클수록 델타체적($V_{xD}$)이 증가하고, 델타의 전면부 길이비($h_d/{\Delta}S$)는 1에 가깝다. 같은 유량조건인 경우에 가동보의 기립 각도가 가장 클 때, 시간당 델타의 퇴적량($Q_s$)은 가장 작았다. 따라서 보의 높이(W)가 클수록 델타의 발달을 억제할 수 있는 효과가 크다.

Keywords

References

  1. Ashida, K., Sawai, K., and Shieh, C. L. (1987). "A study on the delta formation process in a laterally wide basin-laboratory study of delta formation caused by bed load." Annals of Disaster Prevention Research Institute, 30, B-2, 475-491 (in Japanese).
  2. Ashida, K., Sawai, K., and Shieh, C. L. (1988). "A study on the delta formation process in a laterally wide basin-laboratory study of the influence on the delta formation process associated with suspended load and longshore current." Annals of Disaster Prevention Research Institute, 31, B-2, 477-487 (in Japanese).
  3. Ashida, K., Sawai, K., and Shieh, C. L. (1989). "A study on the delta formation process in a laterally wide basin-simulation of the development of delta with/without channels on its plain." Annals of Disaster Prevention Research Institute, 32, B-2, 553-570 (in Japanese).
  4. Chang, H. H. (1982). "Fluvial hydraulics of deltas and alluvial fans." Journal of the Hydraulics Division, ASCE, Vol. 108, No. 11, pp. 1282-1295.
  5. Cho, H. J., and Kang, H. S. (2013). "Effects of control of dam sedimentation by a hydraulic structure in a reservoir." Journal of Korea Water Resource Association, No. 46, No. 12, pp. 1157-1167. https://doi.org/10.3741/JKWRA.2013.46.12.1157
  6. Fan, J., and Morris, G. (1992). "Reservoir sedimentation. I: Delta and density current deposits." Journal of Hydraulic Engineering, ASCE, Vol. 118, No. 3, pp. 354-369. https://doi.org/10.1061/(ASCE)0733-9429(1992)118:3(354)
  7. Graf, W. H. (1984). "Storage losses in reservoirs." Water Power and Dam Construction, Vol. 36, No. 4, pp. 37-40.
  8. Hotchkiss, R. and Parker, G. (1988). Reservoir sediment sluicing - Laboratory study. Hydraulic Engineering, pp. 1073-1078.
  9. Hotchkiss, R. and Parker, G. (1990). "Laboratory modelling of reservoir sedimentation and sluicing: scale considerations." Proceedings International Conference on Physical Modelling of Transport and Suspension, ASCE, pp. 14B.25-14B.30.
  10. Hotchkiss, R. H., and Parker, G. (1991). "Shock fitting of aggradational profiles due to backwater." Journal of Hydraulic Engineering, ASCE, Vol. 117, No. 9, pp. 1129-1144. https://doi.org/10.1061/(ASCE)0733-9429(1991)117:9(1129)
  11. Julien, P. Y. (1995). Erosion and sedimentation. Cambridge University Press, NY, USA.
  12. Lee, K. S. (2018). Development of discharge coefficient of movable weir and analysis of the sediment processes upstream from the weir. Ph. D. dissertation, Korea National University of Transportation, pp. 64-68.
  13. Lee, K. S., Jang, C.-L., and Lee, N. J. (2016). "Analysis of submerged flow characteristics of the improved-pneumatic-movable weir through the laboratory experiments." Journal of Korea Water Resource Association, No. 49, No. 7, pp. 615-623. https://doi.org/10.3741/JKWRA.2016.49.7.615
  14. Lee, K.S., Jang, C.-L., Lee, N.J., and Ahn, S.J. (2014). "Analysis of Flow Characteristics of the improved-pneumatic-movable weir through the Laboratory Experiments." Journal of Korea Water Resource Association, No. 47, No. 11, pp. 1007-1015. https://doi.org/10.3741/JKWRA.2014.47.11.1007
  15. Lee, K. S., Jang, C.-L., Son, K. I., and Hwang, M. H. (2013). "Numerical analysis of the sediment pass-through from the Sangju weir and the Gumi weir by using CCHE2D." Journal of Korean Society on Water Environment, No. 29, No. 6, pp. 813-824.
  16. Mahmood, K. (1987). Reservoir sedimentation: Impact, extent and mitigation. Technical Paper No.71, The World Bank, Washington D.C.
  17. Morris, G. L., and Fan, J. (1997). Reservoir sedimentation handbook. McGraw-Hill, NY, pp. 10.1-10.5.
  18. Soni, J. P., Ranga Raju, K. G., and Garde, R. J. (1980). "Aggradation in streams due to overloading." Journal of the Hydraulics Division, ASCE, Vol. 106, No. 1, pp. 117-132.
  19. Toniolo, H., and Parker, G. (2003). "1D numerical modeling of reservoir sedimentation." Proceedings IAHR Symposium on River, Coastal and Estuarine Morphodynamics, Barcelona, Spain, pp. 457-468.
  20. Wright, L. D., and Coleman, J. M. (1974). "Mississippi river mouth processes: Effluent dynamics and morphologic development." The Journal of Geology, Vol. 82, No. 6, pp. 751-778. https://doi.org/10.1086/628028
  21. Yang, C. T., and Ahn, J. (2009). Xiaolangdi reservoir scouring and silting mechanism and numerical simulation study. Yellow River Engineering Consulting Company, China.