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부유식 해상구조물의 계류를 위한 사질토 지반의 석션파일 설계

Design for Installation of Suction Piles in Sand Deposits for Mooring of Floating Offshore Structures

  • 박철수 (한국건설기술연구원 Geo-인프라연구실) ;
  • 이주형 (한국건설기술연구원 Geo-인프라연구실) ;
  • 백두현 (한국건설기술연구원 Geo-인프라연구실) ;
  • 도진웅 (한국건설기술연구원 Geo-인프라연구실)
  • Park, Chul-Soo (Geotechnical Engrg. Research Div., Korea Institute of Civil Engrg. and Building Technology) ;
  • Lee, Ju-Hyung (Geotechnical Engrg. Research Div., Korea Institute of Civil Engrg. and Building Technology) ;
  • Baek, Du-Hyun (Geotechnical Engrg. Research Div., Korea Institute of Civil Engrg. and Building Technology) ;
  • Do, Jin-Ung (Geotechnical Engrg. Research Div., Korea Institute of Civil Engrg. and Building Technology)
  • 투고 : 2014.03.24
  • 심사 : 2014.09.23
  • 발행 : 2014.10.31

초록

본 연구에서는 국내 서남해 해상지역 시범사업의 부유식 콘크리트 해상구조물 계류를 위한 기초시스템으로서 석션파일을 적용하기 위한 예비설계를 수행하였다. 설계에 앞서 시범사업 대상지역인 서남해안에 대한 지반 및 수리 조건, 재현주기 100년의 환경외력 등 현장 조건을 면밀히 검토하였다. 석션파일은 설계하중에 대한 수평방향 지지력을 만족해야하고, 뿐만 아니라 지반종류 및 강도정수, 유효응력, 침투압 등의 조건에 따른 관입성 검토가 수행되어야 한다. 본 설계에서는 석션파일 직경에 따라 설계외력에 대해 수평방향 안정성을 확보할 수 있는 목표 침설깊이를 설정하고, 침설단계별로 상한석션압 이내에서 관입력과 관입저항력 비교를 통해 설계석션압을 산정하였다. 검토결과 직경 3.0~5.0m 석션파일의 경우 목표 깊이까지 침설이 불가능하였고, 직경 6.0m와 7.0m 석션파일은 각각 침설깊이 8.5m와 8.0m에서 수평방향 안정성 및 설계석션압에 의한 침설을 모두 만족함을 확인하였다.

The preliminary design of suction pile as the supporting system for concrete floating structures was performed for the pilot project of the southwest coast area in Korea. Prior to starting design work, site conditions of the area including ground and hydraulic conditions, and a 100-year return period external force were throughly evaluated. The suction pile for mooring of the offshore floating structures has to satisfy the lateral resistance against external force as well as the penetration ability according to the soil conditions such as soil types, shear strengths, effective stresses, and seepage forces. In the design, the required penetration depths, which were stable for lateral resistance, were evaluated with the diameters of cylindrical suction pile as the final installing ones. And the design suction pressures at each penetrating depths, at which sand boiling did not occur, were assessed through the comparison of penetration and penetrationresistance forces. As a result, it was impossible for suction piles with the diameter range of 3.0~5.0 m to penetrate into required penetration depths. On the other hand, suction piles with the diameter range of 6.0 m and 7.0 m satisfied both the horizontal stability and the penetration ability by design suction pressures at the required penetration depths of 8.5 m and 8.0 m, respectively.

키워드

참고문헌

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