한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

한국지반공학회 (Korean Geotechnical Society)
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암반에 설치된 현장타설말뚝의 극한선단지지력에 관한 연구

A Study on the Ultimate End Bearing Capacity of Drilled Shafts in Rocks

  • 투고 : 2013.05.09
  • 심사 : 2013.10.10
  • 발행 : 2013.11.30
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초록

본 연구에서는 Hoek-cell을 이용한 실내모형실험 및 개별요소해석을 수행하여 말뚝의 직경, 암반의 강도와 불연속면 조건이 암반에 근입된 현장타설말뚝의 선단부 거동에 미치는 영향을 분석하였다. 이를 통해 영향인자를 선정하였고, 실제 현장재하시험 데이터베이스를 구축하여 암반근입 현장타설말뚝의 극한선단지지력 예측식을 제안하였다. 또한, 제안된 극한선단지지력 산정식을 현장재하시험 결과와 비교 분석하여 그 적용성을 검증하였다. 그 결과, 시험말뚝이 근입된 암반의 불연속면 특성을 고려하지 못하고 일축압축강도만을 이용하여 극한선단지지력을 예측하는 기존 제안식들이 일부 재하시험 결과를 과도하게 예측하는 데 비해, 본 연구의 제안식은 선단부 거동 영향인자를 반영하여, 현장말뚝의 극한선단지지력을 적절히 예측하고 있음을 확인할 수 있었다.

The end bearing capacity of rock-socketed drilled shafts under axial loading is investigated by Hoek-cell tests and a numerical analysis. From the test results, it was found that the ultimate end bearing capacity ($q_{max}$) was influenced by pile diameter, rock mass modulus and the spacing of discontinuity. A new ultimate end bearing capacity method is proposed by taking end bearing capacity influence factors, including rock mass discontinuity, based on field data. Through comparisons with other field data, the proposed $q_{max}$ method represents a definite improvement in the prediction of ultimate end bearing capacity of rock-socketed drilled shafts.

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