Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Performance Evaluation of Pull-out Load of a New Type of Double-wall Pile Foundation for Easy Demolition

기초구조물 회수가 용이한 신형식 이중벽 말뚝기초의 인발하중 성능평가

  • Kim, Jae-Hyun (Dept. of Civil Engrg., The College of Art, Culture and Engrg., Kangwon National Univ.) ;
  • Kim, Jeong-Soo (Dept. of Future & Smart Construction Research, Korea Institute of Civil Engrg. and Building Technology) ;
  • Lee, Minjy (Dept. of Civil and Environmental Engrg., Kongju National Univ.) ;
  • Sven, Falcon Sen (Dept. of Civil and Environmental Engrg., Kongju National Univ.) ;
  • Choo, Yun Wook (Dept. of Civil and Environmental Engrg., Kongju National Univ.) ;
  • Hwang, Sung-Pil (Dept. of Geotechnical Research, Korea Institute of Civil Engrg. and Building Technology)
  • 김재현 (강원대학교 문화예술.공과대학 건축토목환경공학부 토목공학전공) ;
  • 김정수 (한국건설기술연구원 미래스마트건설연구본부) ;
  • 이민지 (공주대학교 건설환경공학과) ;
  • ;
  • 추연욱 (공주대학교 건설환경공학과) ;
  • 황성필 (한국건설기술연구원 지반연구본부)
  • Received : 2022.02.04
  • Accepted : 2022.02.27
  • Published : 2022.04.30
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Abstract

Steel pile foundations are widely used for offshore constructions due to their high bearing capacity and efficiency. Typically, offshore structures that have reached the end of their design life are required to be demolished. However, pile foundations are often left on site due to technical and economic limitations. The pile left on the site not only pollutes the environment, but can also cause obstacles for the construction of new structures. Therefore, research is required to completely eliminate these foundations at the site. In this study, a new type of double-wall pile foundation that can drastically reduce the pull-out load was conceptually proposed, and a series of model tests were performed to validate the performance of the double-wall pile foundation. The installation and extraction of the double-wall pile were simulated in dry sand in the model test, and the measured up-lift load was compared to that of the conventional pile. According to the result, the maximum up-lift load induced by the decommissioning of the double-wall pile was reduced by 45% when compared to the traditional pile in dense sand. This study verified the mechanism for reducing the up-lift load of the double-wall foundation and confirmed the possibility of completely decommissioning a pile that has reached the end of its nominal service life.

강재형 말뚝기초는 안정적인 지지력 확보와 높은 시공성으로 해양구조물 기초로 널리 활용되고 있다. 일반적으로 설계수명에 도달한 해양구조물은 해체수순을 밟게 되는데 말뚝기초는 높은 인발하중과 경제적인 이유로 예외적으로 현장에 존치되는 경우가 많다. 현장에 존치된 기초는 환경오염뿐만 아니라 신규구조물을 건설하는데 장애요인이 될 수 있으므로 말뚝기초 완전해체를 위한 연구가 필요한 실정이다. 본 연구에서는 인발하중을 획기적으로 저감시킬 수 있는 신형식 이중벽 말뚝기초를 제안하고 축소모형실험을 통해 인발하중 저감성능을 실험적으로 평가하였다. 이를 위해 축소된 이중벽 말뚝기초를 제작하고 건조된 모래지반에서 말뚝 설치 및 인발 거동을 모사하였으며, 측정된 인발하중을 동등한 단면의 일반말뚝과 비교하였다. 그 결과, 조밀한 모래지반에서 이중벽 말뚝의 최대 인발력이 일반말뚝에 비해 45% 감소되는 것을 확인하였다. 본 연구를 통해 이중벽 말뚝의 인발하중 저감 성능과 메커니즘을 검증하였으며, 설계수명에 도달한 기초를 완전히 회수할 수 있는 가능성을 확인하였다.

Keywords

Acknowledgement

본 연구는 2020년도 강원대학교 대학회계 학술연구조성비와 한국연구재단의 지원(No. NRF-2021R1C1C1011540)으로 수행되었으며, 이에 깊은 감사를 드립니다.

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