대한토목학회논문집 (KSCE Journal of Civil and Environmental Engineering Research)

  • 제28권4C호
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  • Pages.197-203
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  • 2008
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  • 1015-6348(pISSN)
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  • 2799-9629(eISSN)
대한토목학회 (Korean Society of Civil Engeneers)
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풍화된 암반에 근입된 현장타설말뚝의 선단지지거동

End Bearing Behavior of Drilled Shafts in Weathered Rock

  • 권오성 (대림산업(주) 기술연구소) ;
  • 김명모 (서울대학교 공과대학 건설환경공학부)
  • 투고 : 2006.11.27
  • 심사 : 2007.02.03
  • 발행 : 2008.07.31
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초록

풍화된 암반에 근입된 말뚝의 선단지지거동은 신선암의 강도보다는 절리를 포함한 암반 상태에 의존한다. 본 연구에서는 암반상태가 말뚝의 선단지지력에 미치는 영향을 알아보기 위해 먼저 총 4부지의 암반에 근입된 13본의 현장타설콘크리트 말뚝에 대한 재하시험, 그리고 재하시험 부지의 지반조사 자료를 포함하는 데이터베이스를 구축하고, 말뚝선단부의 거동과 암반물성치의 상관관계를 분석하였다. 선단지반반력계수와 암반물성치의 상관관계 분석 결과 암석의 일축압축강도와 지반반력계수 사이에는 일관된 상관관계를 찾을 수 없었으나, 암반의 상태를 나타내는 물성치인 $E_m$, $E_{ur}$, RMR, 그리고 RQD 등과 지반반력계수의 상관계수는 대부분 0.7 이상으로 매우 뛰어난 상관성을 보였다. 또한, 기존의 방법으로 추정한 선단지지력과 실측 선단지지력의 비교를 통해 기존 방법의 적용성을 검증하였다.

The end bearing behavior of piles socketed in weathered/soft rock is generally dependent upon the rock mass conditions with fractures rather than the strength of intact rock. Therefore, a database which includes 13 load tests performed on cast-in-place concrete piles and soil investigation data at the field test sites was made first, and new empirical relationships between the base reaction modulus of piles in rock and rock mass properties were developed. No correlation was found between the compressive strengths of intact rock and the base reaction modulus of weathered/soft rock. The ground investigation data regarding the rock mass conditions (e.g. Pressuremeter modulus and limit pressure, RMR, RQD) was found to be highly correlated with the base reaction modulus, showing the coefficients of correlation greater than 0.7 in most cases. In addition, the applicability of existing methods for the end bearing capacity of piles in rock was verified by comparison with the field test data.

키워드

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