Journal of Advanced Marine Engineering and Technology

The Korean Society of Marine Engineering (한국마린엔지니어링학회)
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A Study on the Soft Ground Subsidence beneath the Jack-up Rig Working for Offshore Wind Turbine Installation

해상풍력발전 설치를 위한 jack-up rig 작업 시 연약지반에 발생하는 지반침하에 관한 연구

  • 이의창 (한국해양대학교 에너지자원공학과) ;
  • 장원일 (한국해양대학교 에너지자원공학과) ;
  • 신성렬 (한국해양대학교 에너지자원공학과)
  • 투고 : 2012.08.10
  • 심사 : 2012.11.22
  • 발행 : 2012.11.30
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초록

With concern for new renewable energy sources rising, the offshore wind turbine energy market is growing. In order to install offshore wind turbines safely in a harsh environment, jack-up rigs need to be used. Recently, a WTIV(Wind Turbine Installation Vessel), which has a self-propelling system, was developed to replace traditional jack-up rigs. Since the jack-up rig works at 60 meters of depth in offshore and the seafloor is composed mostly of soft clay and sand, it is necessary to conduct a stability examination for ground subsidence before using it. This study conducts an improved numerical analysis of the effect of jack-up rig loading on the soft ground by using FLAC3D considering consolidation theory. This includes analyzing the amount of subsidence when applying different cases of surchargings. It can be concluded that the mid-loading method has an advantage as regards clay layers and the pre-loading method has an advantage as regards sand layers.

신재생에너지의 관심이 증가함에 따라 해상풍력발전시장이 확대되고 있다. 열악한 환경에서 해상풍력발전을 안전하게 설치하기 위해서는 jack-up rig를 이용한 작업이 이루어져야하며, 최근에는 기존 jack-up rig의 단점을 보완한 자체추진력을 가진 WTIV가 개발되었다. 이는 60 m이하의 연안에서 주로 작업이 이루어지며, 이러한 지역은 연약 점성토 및 사질토로 jack-up rig 작업 시 지반침하에 대한 안정성 검토가 선행되어야 한다. 본 연구에서는 압밀이론을 고려하여 jack-up rig 작업이 연약지반에 미치는 영향을 FLAC3D를 이용하여 수치해석적인 연구를 진행하였다. 침하정도를 분석하고, 안정적인 jack-up rig 작업을 위해 재하방법을 달리하였다. 본 연구에서 적용한 차등재하방법 중 mid-loading 방법은 clay층에 유리하며, pre-loading 방법은 sand층에 유리한 결과가 나타났다.

키워드

참고문헌

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피인용 문헌

  1. Numerical Analysis of Hydrodynamic Characteristics for Various Types of Jack-up Legs vol.28, pp.5, 2014, https://doi.org/10.5574/KSOE.2014.28.5.371