Journal of Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회논문집)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
권호 표지
DOI QR코드

DOI QR Code

Stability Formula for Rakuna-IV Armoring Rubble-Mound Breakwater

사석방파제 위에 피복한 Rakuna-IV의 안정공식

  • Suh, Kyung-Duck (Department of Civil and Environmental Engineering & Engineering Research Institute, Seoul National University) ;
  • Lee, Tae Hoon (Department of Civil and Environmental Engineering & Engineering Research Institute, Seoul National University) ;
  • Matsushita, Hiroshi (Nikken Kogaku Co., Ltd.) ;
  • Nam, Hong Ki (Korea SE Co., Ltd.)
  • 서경덕 (서울대학교 건설환경공학부) ;
  • 이태훈 (서울대학교 건설환경공학부) ;
  • ;
  • 남홍기 (주식회사코리아에스이)
  • Received : 2013.02.07
  • Accepted : 2013.08.06
  • Published : 2013.08.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, a total of 51 cases of hydraulic model tests has been conducted for various wave conditions and slope angles of breakwater to develop a stability formula for Rakuna-IV armoring a rubble-mound breakwater. The stability number of the formula is expressed as a function of relative damage, number of waves, structural slope, and surf similarity parameter. The stability formula is derived separately for plunging and surging waves, the greater of which is used. The transitional surf similarity parameter from plunging waves to surging waves is also presented. Lastly, to explain the stability of Rakuna-IV to the engineers who are familiar with the stability coefficient in the Hudson formula, the required weight of Rakuna-IV is calculated for varying significant wave height for typical plunging and surging wave conditions, which is then compared with those of the Hudson formula using several different stability coefficients.

본 연구에서는 사석 방파제 위에 피복한 Rakuna-IV에 대하여 파랑조건과 구조물의 경사를 변화시키며 51가지 실험을 수행하여 안정공식을 유도하였다. 안정공식에서 안정수는 상대피해, 파의 개수, 구조물 경사 및 surf similarity parameter의 함수로 표시된다. 안정공식은 권파와 쇄기파에 대하여 따로따로 유도되었으며, 둘 중 안정수를 크게 계산하는 공식을 사용한다. 또한 권파와 쇄기파의 경계가 되는 critical surf similarity parameter를 제시하였다. 마지막으로, Hudson 공식에서 사용되는 안정계수에 익숙한 기술자들에게 Rakuna-IV의 안정성을 설명하기 위하여, 대표적인 권파와 쇄기파 조건에 대하여 유의파고의 변화에 따른 Rakuna-IV의 소요중량을 계산하고, 이를 몇몇 다른 안정계수를 사용한 Hudson 공식의 결과와 비교하였다.

Keywords

References

  1. Goda, Y. (2010). Random Seas and Design of Maritime Structures, 3rd Ed. World Scientific, Singapore.
  2. Hanzawa, M., Sato, H., Takahashi, S., Shimosako, K., Takayama, T. and Tanimoto, K. (1996). New stability formula for wave-dissipating concrete blocks covering horizontally composite breakwaters. Proc. 25th Int. Conf. Coastal Eng., ASCE, Orlando, U.S.A., 1665-1678.
  3. Hong, K. H. and Chun, I. S. (1999). Experimental study for the hydraulic performance of Octopus - A new type of armor block. Journal of the Korean Society of Civil Engineers 19(II-3), 359-374 (in Korean).
  4. Kim, S.-W. and Suh, K.-D. (2010). Estimation of erosion damage of armor units of rubble mound breakwaters attacked by typhoons. Journal of Korean Society of Coastal and Ocean Engineers 22(5), 295-305 (in Korean).
  5. Mase, H., Yasuda, T., Mori, N., Matsushita, H. and Reis, M.T. (2011). Effects of wave steepness and wave breaking on stability of wave dissipating blocks. Proc. Coastal Structures 2011, Yokohama, Japan.
  6. Suh, K. D., Park, W. S. and Park, B. S. (2001). Separation of incident and reflected waves in wave-current flumes. Coastal Engineering 43, 149-159. https://doi.org/10.1016/S0378-3839(01)00011-4
  7. Suh, K. D. and Kang, J. S. (2012). Stability formula for Tetrapods. Journal of Waterway, Port, Coastal and Ocean Engineering 183(3), 261-266.
  8. Van der Meer, J. W. (1987a). Stability of breakwater armor layers- Design formulae. Coastal Engineering 11, 219-239. https://doi.org/10.1016/0378-3839(87)90013-5
  9. Van der Meer, J. W. (1987b). Stability of rubble mound breakwaters, Stability formula for breakwaters armoured with Tetrapods. Report on Basic Research, H462 Volume II, Delft Hydraulics Laboratory.
  10. Van der Meer, J. W. (1988). Stability of cubes, tetrapods and accropode. In: Design of breakwaters, Thomas Telford, London, 71-80.
  11. Vietnam Water Resources University (2011). Experimental study on stability of Nikken Kogaku's new wave dissipating blocks in application to coastal protection works in Vietnam. Vietnam Water Resources University, Vietnam.
  12. Willmott, C. J. (1981). On the validation of models. Physical Geog raphy 2, 184-194.
  13. Yasuda, T., Mase, H., Konishi, H., Matsushita, H. and Tokunaga, S. (2008). Experimental study on stability of new wave dissipating blocks and effects of wave steepness and wave breaking on its stability. Annual Journal of Civil Engineering in the Ocean, 24, 519-524 (in Japanese). https://doi.org/10.2208/prooe.24.519
  14. Yasuda, T., Mase, H., Takahashi, M., Matsushita, H. and Tokunaga, S. (2009). Armor block stability formulae considering effects of wave steepness and wave breaking. Annual Journal of Civil Engineering in the Ocean, 25, 575-580 (in Japanese).