Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
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Comparison of Shear Strength Characteristics of Unsaturated Soil From Triaxial Compression Tests with Direct Shear Tests

삼축시험과 직접전단시험에 의한 불포화토의 전단특성 비교

  • Hwang, Hui-Seok (Dept. of Civil Engineering, Kangwon National University) ;
  • Choi, Young-Nam (Dept. of Civil Engineering, Kangwon National University) ;
  • Park, Byung-Soo (Dept. of Civil Engineering, Gangwon State University) ;
  • Yoo, Nam-Jae (Dept. of Civil Engineering, Kangwon National University)
  • Received : 2016.10.05
  • Accepted : 2016.12.12
  • Published : 2016.12.30
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Abstract

In this paper, shear strength characteristics of an unsaturated soil were compared using triaxial compression tests(CD) and modified direct shear tests and thus feasibility of the newly modified direct shear testing apparatus was confirmed. The shear strength tests of unsaturated state with a soil sample, obtained from a slope where debris flow occurred at Yangpyeong in Kyeunggi province during 2010, were performed. Both tests showed a linear relationship of matric suction with the shear strength under low level of matric suction. The apparent cohesion of the unsaturated soil was also increased linearly with increase of matric suction. As results of comparing two different testing apparatus, estimated values of shear strength parameters of unsaturated soil($c^{\prime}$, ${\phi}^b$) were slightly larger in the modified direct shear tests due to constraint effect of shear box.

본 논문은 삼축압축시험(CD)과 개선된 직접전단시험 결과 얻어진 불포화토의 전단특성을 비교분석하여 새로이 개선된 직접전단시험장비의 실용성을 검증하였다. 2010년 경기도 양평군 토석류 발생사면에서 채취한 시료를 대상으로 불포화토 상태의 전단강도실험을 수행하였다. 다른 두 종류의 실험방법에서 낮은 모관흡수력이 작용하는 경우는 전단강도와 선형적인 관계를 나타내며, 모관흡수력의 증가함에 따라 불포화토의 겉보기 점착력 역시 선형적으로 증가하였다. 다른 두 실험장비에 의한 결과를 비교한 결과, 산정된 불포화토의 강도정수($c^{\prime}$, ${\phi}^b$)는 전단 상자의 구속효과가 있는 개선된 직접전단시험에서 다소 크게 나타났다.

Keywords

References

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