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Effect of geological characteristics on differential weathering of low-graded metasedimentary rock slopes

저변성퇴적암 사면에서 지질특성이 차별풍화에 미치는 영향

  • Jeong, Hae-Geun (K-water Institute, Korea Water Resources Corporation) ;
  • Seo, Yong-Seok (Department of Earth and Environmental Sciences, Chungbuk National University) ;
  • Ihm, Myung-Hyeok (Department of Geotechnical Engineering for Disaster Prevention, Daejeon University)
  • 정해근 (한국수자원공사 K-water 연구원) ;
  • 서용석 (충북대학교 지구환경과학과) ;
  • 임명혁 (대전대학교 지반방재공학과)
  • Received : 2013.05.06
  • Accepted : 2013.05.21
  • Published : 2013.07.31

Abstract

This study evaluates correlation between petrographic characteristics and weathering grade of low-graded metasedimentary rocks mainly consisting of phyllite. Weathering grade of rock material was determined based on the results of geological survey. The Schmidt hammer test was carried out to obtain estimates of strength of rock materials. Point counting and microscopic observation were also conducted to analyze mineral composition and to measure spacing of foliation for 9 rock specimens. As a result of microscopic analysis, as the weathering grade was lower, the quartz was found more in quantity, consequently making rock stronger against weathering process. On the other side, lower weathering grade of rock resulted in less content of mica which is weak against weathering process. In addition, the rock materials with closer foliation spacing are found to be weaker in strength and have higher weathering grade.

Acknowledgement

Supported by : 한국연구재단

References

  1. Cho, Y.H., Lim, D.S., Chun, B.S. (2010), "A case study on the slope collapse and reinforcement method of the phyllite slope", Journal of Korea Geo-Environmental Society, Vol. 11, No. 8, pp. 83-93.
  2. Gupta, A.S., Rao K.S. (2001), "Weathering indices and their applicability for crystalline rocks", Bulletin of Engineering Geology and the Environment, Vol. 6, No. 3, pp. 201-221.
  3. ISRM (1978), "Suggested methods for the quant itative description of discontinuities in rock masses", International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 15, pp. 319-368. https://doi.org/10.1016/0148-9062(78)91472-9
  4. Kim, H.S., Cho, D.S. (1993), "Genesis of talc deposits in the Chungju area, Korea", Journal of Petrological Society of Korea, Vol. 2, No. 2, pp. 95-103.
  5. Kockar, M.K., Akgun, H. (2003), "Methodology for tunnel and portal support design in mixed limestone, schist and phyllite conditions: a case study in Turkey", International Journal of Rock Mechanics & Mining Sciences, Vol. 40, pp. 173-196. https://doi.org/10.1016/S1365-1609(02)00130-2
  6. Koo, H.B., Kim, S.H., Kim, S.H., Lee, J.Y. (2008), "A study on jointed rock mass properties and analysis model of numerical simulation on collapsed slope", Journal of Korean Geotechnical Society, Vol. 24, No. 5, pp. 65-78.
  7. Kwon, Y.I., Jin, M.S. (1974), "Explanatory text of the geological map of Cheong Ju sheet (1: 50,000)", Korea Institute of Geoscience and Mineral Resources.
  8. Lee, B.J., Kim, D.H., Choi, H.I., Kee, W.S., Park, K.H. (1996), "Explanatory text of the geological map of Daejeon sheet(1:250,000)", Korea Institute of Geoscience and Mineral Resources.
  9. Lee, S.H., Kim, M.K. (1997), "Lithogeochemical characteristics of the granitic rocks in Chungju- Chongju area", Journal of Industrial Science, Chongju University, Vol. 15, pp. 109-116.
  10. Lee, S.K., Son, W.H., Jeong, S.H. (2007), "A study on over-break characteristics of tunnel in phillite rock masses", Journal of Geological Society of Korea, Vol. 2007, No. 2007, pp. 169.
  11. Park, B.S., Cho, H., Youn, S.P., Lee, S.H. (2011), "Case study on stability analysis of phyllite rock slopes in national road construction", International Journal of Geo-Engineering, Vol. 3, No. 3, pp. 41-52.
  12. Park, H.I., Lee, J.D., Jeong, J.G. (1977), "Geological map of Korea : Yuseong sheet(1:50,000)", Korea Institute of Geoscience and Mineral Resources.
  13. Powell, C.McA. (1979), "A morphological classification of rock cleavage", Tectonophysics, Vol. 58, No. 1-2, pp. 21-34. https://doi.org/10.1016/0040-1951(79)90320-2
  14. Santi, P.M. (2006), "Field methods for characterizing weak rock for engineering", Journal of Environmental and Engineering Geoscience, Vol. 6, No. 1, pp. 1-11.
  15. Shin, K.J., Kim, S,K., Kim, J.H. (2003), "A case study of failure behavior in phyllite slope of developed rock cleavages", Korean Society for Rock Mechanics Conference, pp. 121-134.
  16. Tanyas, H., Ulusay, R. (2013), "Assessment of structurally-controlled slope failure mechanisms and remedial design considerations at a feldspar open pit mine, western turkey", Engineering Geology, Vol. 155, pp. 54-68. https://doi.org/10.1016/j.enggeo.2012.12.017
  17. Tinoco, F.H., Salcedo, D.A. (1981), "Analysis of slope failures in weathered phyllite", ISRM International Symposium, Japan, pp. 8.
  18. Um, J.K. (2008), "A reinforcement case of slope failure by fractured zone of schist and gneiss", Journal of Korean Geotechnical Society, Vol. 24, No. 8, pp. 34-41.