Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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Estimation on End Vertical Bearing Capacity of Double Steel-Concrete Composite Pile Using Numerical Analysis

수치해석을 이용한 이중 강-콘크리트 합성말뚝 연직지지력 평가

  • Jeongsoo, Kim (Department of Future and Smart Construction Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Jeongmin, Goo (DONG MYEONG Eng. Consultants & Architecture Co., LTD.) ;
  • Moonok, Kim (R&D Laboratory, SPEC Engineering Y&P Co., LTD.) ;
  • Chungryul, Jeong (Department of Future and Smart Construction Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Yunwook, Choo (Department of Civil & Environmental Engineering, Kongju National University)
  • Received : 2022.10.19
  • Accepted : 2022.11.07
  • Published : 2022.12.01
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Abstract

Conventionally, because evaluation methods of the bearing capacity for double steel pipe-concrete composite pile design have not been established, the conventional vertical bearing capacity equations for steel hollow pile are used. However, there are severe differences between the predictions from these equations, and the most conservative one among vertical bearing capacity predictions are conventionally adopted as a design value. Consequently, the current prediction method for vertical bearing capacity of composite pile prediction composite pile causes design reliability and economical feasibility to be low. This paper investigated mechanical behaviors of a new composite pile, with a cross-section composed of double steel pipes filled with concrete (DSCT), vertical bearing capacities were analyzed for several DSCT pile conditions. Axisymmetric finite element models for DSCT pile and surrounding ground were created and they were used to analyze effects on behaviors of DSCT pile pile by embedding depth, stiffness of plugging material at pile tip, height of plugging material at pile tip, and rockbed material. Additionally, results from conventional design prediction equations for vertical bearing capacity at steel hollow pile tip were compared with that from numerical results, and the use of the conventional equations for steel hollow pile was examined to apply to that for DSCT pile.

이중 강-콘크리트 합성말뚝의 설계를 위한 지지력 평가 방법이 정립되지 않아 기존 강관말뚝 설계 지지력식이 활용되고 있다. 그러나 이들 설계식 간 지지력 예측 결과가 상이할 뿐만 아니라 일반적으로 가장 보수적인 결과를 채택하게 된다. 이러한 말뚝 지지력 평가방법은 설계의 신뢰성 및 경제성을 낮추게 된다. 본 논문은 수직하중을 받는 이중 강관 내 콘크리트 채움된 신형식 합성단면(DSCT) 말뚝의 역학적 거동을 수치해석적으로 조사하고, 여러 DSCT 말뚝 조건변화에 따른 연직지지력을 분석하였다. DSCT 말뚝 및 인접지반에 대한 축대칭 유한요소모델을 생성하였고, 이를 활용해 근입깊이, 말뚝 선단 채움재 강성, 말뚝 선단 채움재 높이, 기반암층 종류 변화에 따른 영향을 분석하였다. 또한 해석결과를 말뚝 설계 실무에서 주로 사용하는 선단 지지력 평가식과 비교하여 합성말뚝에 대한 기존 강관말뚝 지지력 산정식의 활용 가능성을 검토하였다.

Keywords

Acknowledgement

본 연구는 국토교통부/국토교통과학기술진흥원(과제번호 21CTAP-C164018-01) 및 해양수산부 "해저공간 창출 및 활용 기술개발(20220364)"사업의 연구비 지원으로 수행되었습니다.

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