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

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
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Influence of Water Depth on Climate Change Impacts on Caisson Sliding of Vertical Breakwater

직립방파제의 케이슨 활동에 미치는 기후변화영향에 대한 수심의 효과

  • Kim, Seung-Woo (Department of Civil and Environmental Engineering, Seoul National University) ;
  • Kim, So-Yeon (Climate change & Coastal Disaster Research Department, Korea Ocean Research and Development Institute) ;
  • Suh, Kyung-Duck (Department of Civil and Environmental Engineering and Integrated Research Institute of Construction and Environmental Engineering, Seoul National University)
  • 김승우 (서울대학교 건설환경공학부) ;
  • 김소연 (한국해양연구원 기후.연안재해연구부) ;
  • 서경덕 (서울대학교 건설환경공학부 및 건설환경종합연구소)
  • Received : 2011.03.26
  • Accepted : 2012.05.14
  • Published : 2012.06.29
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Abstract

Performance analyses of vertical breakwaters were conducted for fictitiously designed breakwaters for various water depths to analyze the influence of climate change on the structures. The performance-based design method considering sea level rise and wave height increase due to climate change was used for the performance analysis. One of the problems of the performance-based design method is the large calculation time of wave transformation. To overcome this problem, the SWAN model combined with artificial neural network was used. The significant wave height and principal wave direction at the breakwater site are quickly calculated by using a trained neural network with inputs of deepwater significant wave height and principal wave direction, and tidal level. In general, structural stability becomes low due to climate change impacts, but the trend of stability is different depending on water depth. Outside surf zone, the influence of wave height increase becomes more significant, while that of sea level rise becomes negligible, as water depth increases. Inside surf zone, the influence of both wave height increase and sea level rise diminishes as water depth decreases, but the influence of wave height increase is greater than that of sea level rise. Reinforcement and maintenance policies for vertical breakwaters should be established with consideration of these results.

기후변화가 구조물의 안정성에 미치는 영향을 분석하기 위해 여러 수심에서 가상적으로 설계된 직립방파제의 성능을 평가하였다. 성능평가에서는 기후변화영향인 해수면 상승과 파고 증가를 고려한 성능설계법이 사용되었다. 성능설계법의 파랑변형 계산과정에서 많은 시간이 요구되는 문제를 극복하기 위해 범용 SWAN 모형에 인공신경망을 결합하였다. 학습된 인공신경망에 심해유의파고와 심해주파향 그리고 조위가 입력되면 구조물 위치에서 유의파고와 주파향이 신속하게 계산된다. 전반적으로 구조물의 안정성은 기후변화영향으로 감소하였지만 수심에 따라 서로 다른 경향을 보였다. 쇄파대 밖에서는 수심이 증가할수록 해수면 상승의 영향은 감소하고 파고 증가의 영향은 증가하였다. 한편, 쇄파대 내에서는 수심이 감소할수록 파고 증가와 해수면 상승의 영향 모두 감소하였다. 하지만 파고 증가의 영향이 해수면 상승의 영향보다 컸다. 이와 같은 결과를 반영하여 직립방파제의 유지보수 및 보강 대책을 수립해야 할 것이다.

Keywords

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  2. Development of Time-Dependent Reliability-Based Design Method Based on Stochastic Process on Caisson Sliding of Vertical Breakwater vol.24, pp.5, 2012, https://doi.org/10.9765/KSCOE.2012.24.5.305