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An Experimental Study on the Estimation Method of Overtopping Discharge at the Rubble Mound Breakwater Using Wave-Overtopping Height

월파고를 이용한 사석경사제의 월파량 산정방법에 관한 실험적 연구

  • Dong-Hoon Yoo (National Korea Maritime and Ocean University) ;
  • Young-Chan Lee (National Korea Maritime and Ocean University) ;
  • Do-Sam Kim (Department of Civil Engineering, National Korea Maritime and Ocean University) ;
  • Kwang-Ho Lee (Department of Civil Engineering, National Korea Maritime and Ocean University)
  • 유동훈 (국립한국해양대학교) ;
  • 이영찬 (국립한국해양대학교 ) ;
  • 김도삼 (국립한국해양대학교 토목공학과 ) ;
  • 이광호 (국립한국해양대학교 토목공학과 )
  • Received : 2024.05.03
  • Accepted : 2024.05.28
  • Published : 2024.06.30

Abstract

Wave overtopping is a significant natural hazard that occurs in coastal areas, primarily driven by high waves, particularly those generated during typhoons, which can cause coastal flooding. The development of residential and commercial areas along the coast, driven by increasing social and economic demands, has led to a concentration of people and assets in these vulnerable areas. This, coupled with long-term sea level rise and an increase in typhoon frequency, has heightened the risk of coastal hazards. Traditionally, the evaluation of wave overtopping volumes has relied on directly measuring the collected volume of water that exceeds the crest height of structures through hydraulic model experiments. These experiments are averaged over a specific measurement period. However, in this study, we propose a new method for estimating individual wave overtopping volumes. We utilize the temporal variation of wave overtopping heights to develop an observation system that can quantitatively assess wave overtopping volumes in actual coastal areas. To test our method, we conducted hydraulic model experiments on rubble mound breakwaters, which are commonly installed along the Korean coast. We introduce wave overtopping discharge coefficients, assuming that the inundation velocity from the structure's crest is the long-wave velocity. We then predict overtopping volumes based on wave overtopping heights and compare and review the results with experimental data. The findings of our study confirm the feasibility of estimating wave overtopping volumes by applying the overtopping discharge coefficients derived in this study to wave overtopping heights.

연안에서 발생하는 월파는 고파랑에 의한 대표적인 자연재해 중 하나이며, 태풍 시 발생하는 월파는 연안침수의 주요 원인으로 작용한다. 최근의 연안역은 사회적·경제적 수요의 증가로 연안을 따라 주거지역 및 상업지역이 집중되고 있어 장기적인 해수면의 상승 및 태풍 빈도의 증가 등으로 인한 연안재해의 위험성이 지속적으로 지적되어 왔다. 지금까지 월파량은 주로 실내 수리모형실험을 통해 구조물의 마루 높이를 초과하는 수괴를 집수함을 통해 직접 수집하여 계측시간의 평균월파량으로 평가해 왔다. 본 연구에서는 실해역에서 발생하는 월파를 정량적으로 평가하기 위한 관측시스템의 개발을 목표로 월파고의 시간변동을 이용하여 개별 월파량을 추정하는 방법을 제안하였다. 우리나라 해안에 많이 설치된 사석경사제를 대상으로 수리모형실험을 수행하였으며, 월파 발생 시 구조물 마루에서 발생하는 범람유속을 장파유속으로 가정한 월파유량계수를 도입하고 월파고로부터 월파량을 예측하여 실험결과와 비교·검토하였다. 그 결과, 본 연구에서 도출된 월파유량계수를 월파고에 적용하여 월파량 추정이 가능함을 확인하였다.

Keywords

Acknowledgement

본 연구는 해양수산과학진흥원(KIMST)의 "월파 정량 관측 기술 개발(20220180)" 사업의 지원을 받아 수행된 연구이며, 연구비 지원에 감사드립니다.

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