Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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A Comparison of Roughness Measurement and Load Transfer Test for the Calculation of Unit Skin Friction of Pile Foundation in Soft Rocks

기초 연암부 벽면거칠기 시험과 하중전이 시험 결과의 비교 및 단위주면마찰력의 산정에 대한 연구

  • Received : 2023.06.14
  • Accepted : 2023.06.23
  • Published : 2023.06.30
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Abstract

One of the methods for calculating unit skin friction of soft-rock-socket parts for cast-in-place piles involves the roughness measurement of the parts. The measurements are conducted during the excavation stage. A roughness measuring device is installed in the excavation hole and the unit skin friction is calculated from the measured surface roughness of the rock socket. Herein, the results of roughness measurement of rock-socket parts in cast-in-place piles and that of load transfer tests are analyzed and compared. The unit skin friction from the roughness measurements can be converted into unit skin friction corresponding to the displacement of a pile generated in a load transfer test. A reduction factor is given as Rf = -0.14n + 1.48.

현장타설말뚝의 연암 근입부의 단위주면마찰력을 산정하는 방법 중 암반 벽면거칠기에 의한 산정 방법이 있다. 현장타설말뚝의 굴착 시공 시 암반 굴착공에 거칠기 장치를 설치하고 벽면 거칠기 모양을 측정하고 그 결과를 이용하여 주면마찰력을 산정하는 것이다. 본 연구에서는 암반벽면의 거칠기를 직접 측정한 결과와 하중전이 시험결과를 비교분석하여 거칠기시험에 의한 단위주면마찰력을 말뚝의 발생 변위에 대응하는 단위 주면마찰력으로 변환할 수 있도록 저감계수 Rf = -0.14n + 1.48(여기서, n은 하중전이시험에서 도출된 발생변위 δ를 말뚝직경 D로 나눈 변위비)을 제안하였다.

Keywords

Acknowledgement

This work was supported by Dong-eui University Grant (202301400001).

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