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2018 Vol.28, Issue 6 Preview Page
December 2018. pp. 584-595
Abstract

This study conducted direct shear test on about 290 sorts of materials such as sandy soil, clayey soil and gravely soil to present proper standard on shear strength of soil. Shear strength of soil in large scale tends to show that angle of internal friction increases as sand contents grow and it ranges 23.5°~34.9° with cohesion of 2.0 kPa~15.7 kPa. Elastic modulus was visibly distinct by load, and which increased approximately 80% as vertical load grows. Angle of internal friction arranging 15.0°~28.6° on clayey soil decreased as clay contents rises and cohesion increase in regular scale. Elastic modulus tends to increase initial elastic modulus with almost same growing rate. While angle of internal friction on gravely soil indicates 29.9°~36.7° which hardly shows distinctive features. According to test in detail, cohesion of SW (well-graded sand), SP (poorly-graded sand), SC (clayey sand) and SM (silty sand) indicates value by 94%, 78% and 59% comparing to SC, SW and SP respectively. Angle of internal friction of ML (low-liquid limit silt) and CL (low-liquid limit clay) appears almost same features, and MH (high-liquid limit silt) despite of 88% value of ML. Cohesion among them varies with similar growing rate.

흙의 전단강도의 적절한 기준을 제시하기 위해 모래질, 점토질, 자갈질의 약 290 여개의 재료에 대하여 직접전단시험을 수행하였다. 흙의 대분류에 의한 모래질 흙의 전단강도는 모래 함유율이 많은 흙일수록 내부마찰각은 증가하는 경향이 뚜렷하게 나타났으며, 그 범위는 23.5°~34.9°에 분포하고 있는 것으로 나타났고, 점착력은 2.0 kPa~15.7 kPa 사이에서 골고루 분포하는 것으로 나타났다. 탄성계수는 하중단계에 따라 뚜렷하게 구분할 수 있었으며, 수직하중이 증가할수록 약 80%씩 증가하였다. 점토질 흙의 내부마찰각은 15.0°~28.6°의 범위에서 점토성분 함유율이 많아질수록 감소하는 경향이 나타났고, 점착력은 일정한 범위로 증가하는 경향이 나타났다. 점토질 흙의 탄성계수는 거의 같은 증가비로 초기탄성계수만 약간 증가하는 경향을 나타내었다. 자갈질 흙의 내부마찰각은 29.9°~36.7°의 범위로 뚜렷한 특성을 파악할 수 없었다. 세부분류에 따른 SW(입도분포가 좋은 모래), SP(입도분포가 나쁜 모래), SC(점토 섞인 모래), SM(실트 섞인 모래)의 점착력은 실트함유율이 가장 많은 SM 시료에 비해 SC는 약 94%, SW는 약 78%, SP는 약 59% 정도 값을 나타내었다. 또한 내부마찰각은 ML(액성한계가 낮은 실트)과 CL(액성한계가 낮은 점토)이 거의 같은 거동 특성을 나타내었고, MH(액성한계가 높은 실트)는 ML의 약 88% 값을 나타내었다. 점착력에 대한 변화는 거의 비슷한 증가비를 나타내었다.

References
  1. Byung Ki Park, Moon Soo Lee, Gwon Su Kang, Jae Hyeok Yang, 1996, A Shear Properties of Decomposed Granite Soil, Journal of The Korean Society of Civil Engineers (Ⅲ) (In Korean).
  2. Ja Yeong Jeong, 2002, Comparison of Shear Parameters using Different Direct Shear Tests, Master's thesis. Jeonnam National University (In Korean).
  3. Jae Hyeok Yang, 1997, A Study on Shear Strength Properties of Decomposed Granit Soil, Master's thesis, Chonnam National University (In Korean).(In Korean).
  4. Jeong Geun Jeong, 2015, A Study on the Characteristics of Shear Strength Parameters of Various Soils, Doctoral dissertation, Changwon University (In Korean).
  5. Miura, N. and O-hara, S. 1979, Particle-crushing of a Decomposed Granite Soils under Shear Stresses, Soils and foundations, Vol, 19, NO. 3, pp. 1-14.
  6. Moon Soo Lee, Kwang Chan Lee, 1999, An Evaluation of Shear Strength Parameters (c,φ) for Weathering Decomposed Granite Soil, Journal of the Korean Geotechnical Society, Vol. 15, No. 2, pp.181∼194 (In Korean).
  7. Murata, H., Hyodo, M., & Yasufuku, N., 1988, Compression and Shear Characteristics of Undisturbed Weathered Residual Soil Masado, Proc. of Int. Conf. on Engineering Problems of Residual Soils, pp. 643-648.
  8. Onitsuka, K., & Yoshitake, S., 1985, Mechanical Properties and Strength Anisotropy of Decomposed Granite Soils, Soils and Foundation, Vol. 25, No. 2, pp. 14-30.10.3208/sandf1972.25.2_14
  9. Yong Hwan Choi, Gwang Chan Lee, Jong Ryeol Kim, Byeong Gi Park, 1999, Shear Strength Characteristics of Undisturbed Decomposed Granite Soil under Variations of Normal Stress, Journal of The Korean Society of Civil Engineers (Ⅱ) (In Korean).
Information
  • Publisher :Korean Society for Rock Mechanics and Rock Engineering
  • Publisher(Ko) :한국암반공학회
  • Journal Title :Tunnel and Underground Space
  • Journal Title(Ko) :터널과 지하공간
  • Volume : 28
  • No :6
  • Pages :584-595
  • Received Date :2018. 10. 10
  • Accepted Date : 2018. 10. 26