Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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Modification of Terzaghi's Earth Pressure Formula on Tunnel Considering Dilatancy of Soil

지반의 팽창성을 고려한 터널의 테르자기 토압공식 수정

  • 한희수 (금오공과대학교 토목공학과) ;
  • 조재호 (금오공과대학교 대학원 토목공학과) ;
  • 양남용 (금오공과대학교 대학원 토목공학과) ;
  • 신백철 (금오공과대학교 대학원 토목공학과)
  • Received : 2011.05.12
  • Accepted : 2011.09.19
  • Published : 2011.11.01
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Abstract

In this study, Terzaghi's formula was modified to solve problems considering the dilatancy effect of the soil for estimating the earth pressure acting on tunnel. It is performed for the comparison with Terzaghi's formula and modified Terzaghi's formula, tunnel model test result of Kobe University Rock Mechanics Laboratory. From comparison results of the earth pressure acting on tunnel, the earth pressure calculated by the Terzaghi's formula was estimated largest value. The earth pressure measured through the tunnel model test was least value. The difference between the earth pressure derived from Terzaghi's original formula and that derived from the modified formula was caused by the dilation effect, which was caused by the soil volume change. The difference between the earth pressure derived from the modified formula and the earth pressure measured through the tunnel model test, earth pressure results from the energy making failure surface. The results of FEM analysis were almost consistent with the results of mathematical analysis.

본 연구에서는 터널의 상부에 작용하는 토압을 평가하는데 있어서 기존의 Terzaghi 공식이 가지는 문제점을 해결하기 위해 흙의 팽창성(Dilatancy)을 고려하여 Terzaghi 공식을 수정하였다. Terzaghi 공식과 수정식에 대한 수학적 해석결과, 터널의 토압은 수정식이 Terzaghi 공식에 비해 작게 나타났으며 토피고가 커질수록 그 차이는 증가하였다. 터널모형실험 결과와 비교해 본 결과, Terzaghi 공식에 의해 계산된 상부토압은 굴착 전 토압의 약 70%이며, 수정식에 의하면 약 60% 정도로 나타났고, 터널모형실험에 의해 측정된 토압은 약 40% 정도 임을 볼 수 있었다. 또한 유한요소해석을 이용하여 Terzaghi 공식과 수정식에 의해 산정된 터널 상부토압과 전단변형률을 비교해본 결과 수학적 해석결과와 동일하게 수정식이 Terzaghi 공식보다 작게 나타났다.

Keywords

Acknowledgement

Supported by : 국립금오공과대학교

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