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

한국지반환경공학회 (Korean Geo-Environmental Society)
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점토함유량에 따른 편마풍화토 비탈면의 안정성 평가

Stability Evaluation of Weathered Gneiss Soil Slopes according to Clay Content

  • Hyunsu Park (Dept. of Civil & Environ. Eng., Dankook University) ;
  • Byeongsu Kim (Dept. of Civil & Environ. Eng., Dankook University)
  • 투고 : 2023.08.03
  • 심사 : 2023.09.25
  • 발행 : 2023.10.01
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초록

본 연구에서는 국내의 대표적 풍화토인 편마풍화토에 점토함유량 0%, 5%, 10%의 혼합토로 조성된 비탈면에 대해 강우 시 침투거동을 조사하고, 강우침투로 인한 불포화 비탈면의 안정성을 검토했다. 이를 위해 본 연구에서는 불포화 함수특성시험을 통해 함수특성곡선을 획득했고, 포화 삼축압축시험을 통해 강도정수를 얻었다. 얻어진 결과를 토대로, 침투해석과 안정해석을 통해 비탈면의 강우침투로 인한 포화대 형성과 안전성에 점토함유량과 선행강우 효과를 나타내는 초기흡수력이 미치는 영향에 대해 조사하였다. 그 결과, 지반의 초기흡수력이 높을수록 비탈면의 포화대 형성이 늦춰졌다는 것을 알았다. 또한 점토함유량이 증가할수록 지반의 전단강도 증대와 더불어 강우침투에 대한 저항성을 높이는 효과를 가지며, 비탈면의 안전성을 크게 향상시킨다는 것을 알 수 있었다.

In this study, the infiltration behavior of slopes composed of mixed soils with clay contents of 0%, 5%, and 10% in weathered Gneiss soil, which is a representative weathered soil in Korea, was investigated, and the stability of unsaturated slopes due to rainfall infiltration was examined. For this, in this study, the soil water characteristic curve was obtained through the water retention test, and the strength constant was obtained through the triaxial compression test. Based on the obtained results, the influence of clay content and antecedent rainfall effect (i.e., initial suction) on the formation of saturated zone (i.e., wetting band) and slope stability due to rainfall infiltration was examined through infiltration and stability analyses. As a result, it was found that the hig her the initial suction, the slower the formation of the saturated zone on the slope. In addition, it was found that as the clay content increases, the shear strength of the ground increases and the resistance to rainfall infiltration increases, and eventually the slope stability is greatly improved.

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참고문헌

  1. Byun, Y.S., Kim, J.I., Baek, S.I. and Chun, B.S. (2012), An analytical study on influence of gradients on section characteristics of river banks, Journal of Koean Geo-Eviornmental society, Vol. 13, No. 3, pp. 13~19 (in Korean).
  2. Fredlund, D.G. and Xing, A. (1994), Equations for the soil-water characteristic curve, Canadian Geotechnical Journal, Vol. 31, No. 4, pp. 521~532.
  3. Fredlund, D.G., Morgenstern, N.R. and Widger, R.A. (1978), The shear strength of unsaturated soils, Canadian Geotechnical Journal, Vol. 15, No. 3, pp. 313~321.
  4. Fredlund, D.G., Xing, A. and Huang, S. (1994), Predicting the permeability function for unsaturated soils using the soil-water characteristic curve, Canadian Geotechnical Journal, Vol. 31, No. 3, pp. 533~46.
  5. GEO-SLOPE International Ltd. (2021), Computer program SEEP/W for finite element seepage analysis, User's guide, Calgary, Alta, Canada.
  6. GEO-SLOPE International Ltd. (2021), Computer program SLOPE/W for slope analysis, User's guide, Calgary, Alta, Canada.
  7. Kim, B.S. and Park, S.W. (2013). Effect of rainfall-patterns on slope stability in unsaturated weathered soils, Journal of the Korean Society of Civil Engineers, Vol. 33, No. 3, pp. 1027~ 1035 (in Korean).
  8. Kim, S.K., Ryu, C.H. and Kim, D.H. (1999), Infiltration characteristics of unsaturated decomposed soils, Journal of the Korean Society of Civil Engineers, Vol. 19, No. III-5, pp. 995~ 1002 (in Korean).
  9. Kim, S.K. and Ryu, C.H. (2000), Shear strength of unsaturated decompsed soils, Journal of the Korean Society of Civil Engineers, Vol. 20, No. 2-C, pp. 109~118 (in Korean).
  10. Kim, J.S., Park, H.S., Kim, B.S. and Park, S.W. (2019), Field monitored unsaturated hydraulic behavior on a roadside soil slope: a case study, Int. J. Highw. Eng., Vol. 21, No. 1, pp. 43~50 (in Korean). https://doi.org/10.7855/IJHE.2019.21.1.043
  11. Kim, J.H., Park, S.W., Jeong, S.S., and Yoo, J.H. (2002), A study of stability analysis on unsaturated weathered slopes based on rainfall - induced wetting, Journal of the Korean Geothcnical Society, Vol. 18, No. 2, pp. 123~136 (in Korean).
  12. Kim, J.H., Kim, H.K., Kim, B.S., and Park, S.W. (2016), Impacts of rainfall events and distribution on unsaturated soil slope analysis, Journal of the Korean Geothcnical Society, Vol. 32, No. 1, pp. 35~43 (in Korean). https://doi.org/10.7843/kgs.2016.32.1.35
  13. Lambe, P.C. (1996), Residual soils. In: special report 247. Landslides: investigation and mitigation, Washington DC: TRB, National Research Council, pp. 507~524.
  14. Lee, S.R., Oh, T.K., Kim, Y.K., and Kim, H.C. (2009), Influence of rainfall intensity and saturated permeability on slope stability during rainfall infiltration, Journal of the Korean Geothcnical Society, Vol. 25, No. 1, pp. 65~76 (in Korean).
  15. Ng, C.W.W. and Shi, Q. (1998), A numerical investigation of the stability of unsaturated soil slopes subjected to transient seepage, Computers and geotechnics, Vol. 22, No.1, pp. 1~28.
  16. Park, S.W. and Shin, G.H. (2009), Stability analysis on unsaturated gneiss weathered soil slopes considering wetting path soil-water characteristic curve, Journal of the Korean Society of Civil Engineers, Vol. 29, No. 5C, pp. 191~198 (in Korean).
  17. Park, S.W., Park, J.Y., Tae, D.H. and Sim, Y.J. (2010), Effects of overburden pressure and clay content on water retention characteristics of unsaturated weathered soils, Journal of the Korean Society of Civil Eng ineers, Vol. 30, No. 1C, pp. 53~63 (in Korean).
  18. Road design manual (1996), Earthwork and drainage, p. 89.
  19. Ryu, C.H. (2003), Estimation of slope stability during the change of matric suction, Journal of the Korean Society of Civil Engineers, Vol. 23, No. 4C, pp. 195~291 (in Korean).
  20. Song, Y.S., Yoo, Y.J., Kim, T.W. and Kim, J.H. (2021), Comparison of rainfall seepage characteristics of gneiss and granite weathered soil, Journal of the Korean Geothcnical Society, Vol. 37, No. 6, pp. 21~28 (in Korean).
  21. Vanapalli, S.K., Fredlund, D.G., Pufahl, D.E. and Clifton, A.W. (1996), Model for prediction of shear strength with respect to soil suction, Canadian Geotechnical Journal, Vol. 33, No. 3, pp. 379~392.
  22. Yu, N.D., Jeong, S.S., Kim, J.H. and Park, S.W. (2004), Effect of rainfall-induced infiltration on unsaturated weathered soils with varying clay contents, Journal of the Korean Geothcnical Society, Vol. 20, No. 8, pp. 159~166 (in Korean).