Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Evaluation Method for Uplift Load-carrying Capacity of Inclined Group Micropiles in Dense Sand

조밀한 사질토지반에서 경사로 설치된 그룹 마이크로파일의 인발지지력 평가방법

  • Kyung, Doohyun (Dept. of Civil and Environmental Engrg., Yonsei Univ.) ;
  • Kim, Garam (Dept. of Civil and Environmental Engrg., Yonsei Univ.) ;
  • Kim, Incheol (Dept. of Civil and Environmental Engrg., Yonsei Univ.) ;
  • Lee, Junhwan (Dept. of Civil and Environmental Engrg., Yonsei Univ.)
  • 경두현 (연세대학교 토목환경공학과) ;
  • 김가람 (연세대학교 토목환경공학과) ;
  • 김인철 (연세대학교 토목환경공학과) ;
  • 이준환 (연세대학교 토목환경공학과)
  • Received : 2016.12.14
  • Accepted : 2017.01.16
  • Published : 2017.01.31
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Abstract

In the present study, uplift load carrying behavior of micropiles with installation angle and pile spacing was investigated based on uplift load tests using single and group micropiles. In addition, evaluation methods of uplift load carrying capacity of group micropiles were proposed based on FHWA (2005) and Madhav (1987) and they were compared with test results to confirm the validity of proposed methods. From the test results, uplift load carrying capacities of single and group micropiles increased with the increase of the installation angle up to $30^{\circ}$, whose values also increased slightly with increasing pile spacing. For the proposed method based on FHWA (2005), the estimated values were similar to measured values up to $15^{\circ}$ of installation angle and 5D of pile spacing. For the proposed method based on Madhav (1987), on the other hand, it was observed that the estimated values were in good agreement with measured values in all installation conditions.

본 연구에서는 단일 마이크로파일의 인발재하시험과 그룹 마이크로파일 인발재하시험 결과를 토대로 마이크로파일의 설치각도와 설치간격에 따른 인발지지특성을 확인하였다. 또한 FHWA(2005)의 방법과 Madhav(1987)의 방법을 토대로 지지력평가방법을 제안하고, 시험결과와 비교하여 그 적정성을 검토하였다. 시험결과, 단일 및 그룹마이크로파일의 인발지지력이 설치각도 30도까지 증가하는 것으로 나타났으며, 설치간격이 증가함에 따라 그 값이 다소 증가되는 것으로 나타났다. 제안된 FHWA(2005)의 방법의 경우, 수정된 방법을 통한 예측 값이 설치각도 15도의 5D조건까지 유사한 것으로 나타났다. 반면, 제안된 Madhav(1987)의 방법의 경우에는 모든 설치조건에서의 측정값과 수정된 방법을 통한 예측 값이 비교적 유사한 것으로 나타났다.

Keywords

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