KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Analysis of Pile Behavior according to Bearing Condition for Vertical Extension Remodeling

수직증축 리모델링 시 말뚝지지 조건에 따른 말뚝기초 거동 분석

  • Noh, Yujin (Chungnam National University) ;
  • Park, Jongjeon (Ilshin Geological Engineering) ;
  • Oh, Kyuoung Seok (GS E&C) ;
  • Jang, Seo-Yong (Chonnam National University) ;
  • Ko, Junyoung (Chungnam National University)
  • 노유진 (충남대학교 토목공학과) ;
  • 박종전 (일신지질 서울지사) ;
  • 오경석 (GS건설 중부지사(충남대학교 토목공학과)) ;
  • 장서용 (전남대학교 건축공학과) ;
  • 고준영 (충남대학교 토목공학과)
  • Received : 2023.11.20
  • Accepted : 2024.01.09
  • Published : 2024.04.01
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Abstract

In this study, three-dimensional finite element analysis was used to analyze the behavior of existing and reinforcing piles according to the pile support conditions for vertical extension remodeling. Cap support conditions (group pile, piled raft foundation) and pile tip conditions (rock, soil embedment) were considered as factors influencing existing and reinforcing piles behavior. For the quantitative analysis of existing and reinforcing piles, the displacement, load distribution ratio, and axial force by depth according to the analysis stage were analyzed. As a result of the analysis, it was confirmed that the largest settlement occurred in the reinforcing pile due to the pre-loading method. In particular, a large amount of settlement occurred in group piles regardless of the embedment conditions. In the piled raft foundation, it was confirmed that the displacement and load distribution ratio of existing piles and reinforcing piles were reduced due to the influence of the raft. The axial force by depth showed a difference between group pile and piled raft foundation, which appears to be a major factor affecting displacement and load distribution ratio. Based on the numerical analysis results, it was confirmed that cap support conditions and pile tip embedment conditions should be considered in the design of pile foundations for vertical extension remodeling.

본 연구에서는 3차원 유한요소 해석을 이용하여 기존 건축물의 수직증축 리모델링을 위한 말뚝지지 조건에 따른 기존 및 보강말뚝의 거동에 대해 분석하였다. 수치해석에서 기존 및 보강말뚝 거동의 영향인자로는 캡지지 조건(군말뚝 기초, 말뚝지지 전면기초)과 기존말뚝의 선단근입조건(암반근입, 토사근입)을 고려하였다. 기존말뚝과 보강말뚝의 정량적 거동 분석을 위해 침하량, 하중분담률, 해석 단계에 따른 심도별 축력을 결과로 도출하였다. 분석 결과, 선재하공법 적용에 기인하여 보강말뚝에서 가장 큰 침하량이 발생한 것을 확인하였다. 특히 선단근입조건에 관계없이 군말뚝에서 큰 침하량이 발생하였다. 말뚝지지 전면기초에서는 기초판(Raft)의 영향으로 인해 침하량 및 기존말뚝과 보강말뚝의 하중분담률이 작아지는 것을 확인하였다. 심도별 축력 분포도에서는 군말뚝과 말뚝지지 전면기초 간의 축력 분포에 차이가 나타났으며, 이는 침하량과 하중분담률에 영향을 미치는 주요 요소로 작용하는 것으로 보인다. 수치해석 결과를 바탕으로 수직증축 리모델링을 위한 말뚝기초 설계에 있어서 캡지지 조건과 선단근입 조건을 고려해야 함을 확인하였다.

Keywords

Acknowledgement

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2022R1C1C1011477). This paper has been written by modifying and supplementing the KSCE 2023 CONVENTION paper.

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