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2015 Vol.31, Issue 9 Preview Page
Critical Buckling Characteristics of Micropiles Under Axial Loads

축하중을 고려한 마이크로파일의 임계좌굴특성

Hyeon-Sik Jeong1
,
In-Soo No2
,
Yeong-Seang Lee3*
정 현식1
,
노 인수2
,
이 영생3*
1PE, Director, Dept. of Geotechnical Engrg., Kang-ho Eng. Co.
2President of Shinsegi Const. Co.
3Prof., Dept. of Civil Engrg., Kyonggi Univ.
1강호엔지니어링건축사사무소 이사
2신세기건설주식회사 대표이사
3경기대학교 토목공학과 교수
*교신저자. *Corresponding Author. 
30 September 2015. pp. 39-51
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Abstract

In these days several research efforts have provided the knowledge of bearing capacity behavior of micropile with various soil conditions as its application to foundation retrofit works has increased. However, most of the domestic researches focused mainly on bearing behavior of Case-I and Case-II type micropiles, whereas structural verification research was insufficient in relation with bulking behavior in particular. In this respect, this study was perfomed to understand the critical buckling characteristics of micropiles under axial load with various steel bars and grout conditions. As a result, it was found that a critical buckling shear strength of a micropile increases for smaller diameter micropile and a critical buckling load decreases with a longer length in the condition under the critical buckling length. Also, a method to evaluate a buckling possibility and yield behavior under axial compressive load conditions is proposed.

Keywords
Micropile
Buckling load
Critical buckling shear strength
p-y curve
Yield lateral displacement

근래 구조물 기초보강을 위한 마이크로파일공법의 적용사례가 점차 증가하고 있으며, 이에 따른 관련 연구가 다수 수행되고 있다. 그러나 국내 연구는 대부분 Case. I, II-Type의 지지거동에 국한되어 마이크로파일 자체의 구조적 검토에 대한 연구는 미미한 실정이다. 따라서 본 논문에서는 국내에서 주로 사용되는 마이크로 파일에 대한 각각의 강봉 및 그라우트조건에 따른 좌굴특성을 검토하였다. 검토결과 마이크로파일 직경이 작을수록 지반의 임계좌굴점착력()는 증가하게 되며, 특히 임계좌굴길이() 이하에서는 마이크로파일 길이가 길수록 임계좌굴하중()이 감소함을 알 수 있었다. 또한 축하중을 받는 마이크로파일의 좌굴파괴와 압축파괴 가능성을 구분, 평가할 수 있는 방법을 제시하였다.

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Received : July 13th, 2015
19
Revised  : September 1st, 2015
20
Accepted : September 5th, 2015
Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 31
  • No :9
  • Pages :39-51
  • Received Date : 2015-07-13
  • Revised Date : 2015-09-01
  • Accepted Date : 2015-09-05
  • DOI :https://doi.org/10.7843/kgs.2015.31.9.39
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