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

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
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Numerical Analysis on Liquefaction Countermeasure of Seabed under Submerged Breakwater using Concrete Mat Cover (for Regular Waves)

콘크리트매트 피복을 이용한 잠제하 해저지반에서의 액상화 대책공법에 관한 수치해석(규칙파 조건)

  • Lee, Kwang-Ho (Dept. of Energy Resources and Plant Eng., Catholic Kwandong University) ;
  • Ryu, Heung-Won (Dept. of Civil and Environmental Eng., Graduate School, Korea Maritime and Ocean University) ;
  • Kim, Dong-Wook (Dept. of Civil and Environmental Eng., Graduate School, Korea Maritime and Ocean University) ;
  • Kim, Do-Sam (Dept. of Civil Eng., Korea Maritime and Ocean Univ.) ;
  • Kim, Tae-Hyung (Dept. of Civil Eng., Korea Maritime and Ocean Univ.)
  • 이광호 (가톨릭관동대학교 에너지자원플랜트공학과) ;
  • 류흥원 (한국해양대학교 대학원 토목환경공학과) ;
  • 김동욱 (한국해양대학교 대학원 토목환경공학과) ;
  • 김도삼 (한국해양대학교 건설공학과) ;
  • 김태형 (한국해양대학교 건설공학과)
  • Received : 2016.10.28
  • Accepted : 2016.12.22
  • Published : 2016.12.31
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Abstract

When the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure is generated significantly due to pore volume change associated with rearrangement soil grains. This effect leads a seabed liquefaction around and under structures as a result from decrease in the effective stress, and the possibility of structure failure is increased eventually. These facts shown above have been investigated in the previous studies related to regular and irregular waves. This study suggested a concrete mat for preventing the seabed liquefaction near the submerged breakwater. The concrete mat was mainly used as a countermeasure for scouring protection in riverbed. According to installation of the concrete mattress, the time and spatial series of the deformation of submerged breakwater, the pore water pressure, and the pore water pressure ratio in the seabed were investigated. Their results were also compared with those of the seabed unprotected with the concrete mat. The results presented were confirmed that the liquefaction potential of seabed under the concrete mattress is significantly reduced under regular wave field.

잠제와 같은 중력식구조물하 해저지반에 고파랑이 장시간 작용하는 경우 지반을 구성하는 토립자내 간극의 체적 변화과정에서 과잉간극수압이 크게 발생될 수 있고, 이에 따른 유효응력의 감소에 의하여 구조물 근방 및 하부지반이 액상화될 수 있으며, 종국에는 구조물이 침하파괴될 가능성이 있다는 사실이 규칙파 및 불규칙파 조건하의 선행연구에서 규명되었다. 본 연구에서는 잠제 주변지반에서 발생되는 액상화를 방지하기 위한 대책공법으로 주로 하천에서 세굴방지공으로 사용되어온 콘크리트매트를 해저지반상에 포설하는 방안을 제시하고, 이에 따른 잠제와 콘크리트매트를 포함한 구조물의 동적변위, 지반내 간극수압과 간극수압비 등을 콘크리트매트가 적용되지 않은 원지반의 경우와 비교 검토한다. 이로부터 콘크리트매트하의 해저지반내에서 상대밀도의 증가에 따라 액상화 가능성을 크게 줄일 수 있다는 것을 규칙파 작용하의 수치해석으로부터 확인할 수 있었다.

Keywords

References

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