Journal of the Society of Disaster Information (한국재난정보학회 논문집)

The Korean Society of Disaster Information (한국재난정보학회)
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Evaluation of Stability of Slope with Granite Weathered Soil considering Rainfall Events

강우사상을 고려한 화강풍화토 비탈면의 안정성 평가

  • Kim, Gyu-Hyeong (Department of Civil and Environmental Engineering, Daejin University) ;
  • Hwang, Eui-Pil (Department of Civil and Environmental Engineering, Daejin University) ;
  • Lee, Kang-Il (Department of Civil Engineering, Daejin University)
  • Received : 2018.10.27
  • Accepted : 2018.12.03
  • Published : 2018.12.31
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Abstract

Purpose: This study conducted a slope stability study considering changes in the ground water level due to rain phenomena and the duration of rainfall, that is for the purpose of analyzing the stability of the slope surface of the cut section, seepage numerical analysis is performed by height of slope and rainfall accident, and the characteristics of rainfall was applied reasonably in order to determine the slope change during rain by analyzing rainfall and rainfall pattern due to climate change. Results: As a result of numerical analysis of stability for slope composed of the granite weathered soils according to the characteristics of rainfall(Uniform Rainfall, US Army Corps., Huff's method - 1/4, 4/4), Conclusion: The higher the slope, the smaller the safety factor of the slope, the smaller the elevation of the ground water level as the rainwater seepage does not reach the underground water level. In addition, the ground water level was assessed to be rose significantly in condition of case 3 Huff's method - 1/4, rain pattern with the largest initial rainfall duration, and the safety factor was analyzed to be small.

연구목적 : 본 연구는 기후변화에 따른 강우량 및 강우패턴을 분석하여 강우시 비탈면 거동을 파악하기 위해 강우사상을 합리적으로 적용하여 절토부 비탈면 안정성해석에 활용하고자 수치해석기법을 이용하여 비탈면 높이별, 강우사상별 침투해석을 실시하여 강우사상 및 강우지속시간에 따른 지하수위 변화를 고려한 비탈면 안정성검토를 실시하였다. 연구결과 : 강우사상(Uniform Rainfall, US Army Corps., Huff 4분위법 중 1/4법 및 4/4법)에 따른 화강풍화토 비탈면의 수치해석결과 비탈면이 높을수록 침투된 강우가 지하수위까지 빠르게 도달하지 못하여 지하수위 상승은 작아지고, 비탈면의 안전율도 작게 분석되었다. 결론 : 초기강우강도가 제일 큰 강우패턴 Case 3조건인 Huff 4분위법 중 1/4법에서 지하수위 상승량이 제일 크게 나타났으며, 안전율은 가장 작게 나타났다.

Keywords

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Fig. 1. Rainfall conditions on Uniform Rainfall

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Fig. 3. Rainfall conditions on Huff`s 1/4 method

JNJBBH_2018_v14n4_421_f0003.png 이미지

Fig. 5. Stability and seepage analysis section(Slope hight H=15m)

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Fig. 6. SWCC and coefficient of permeability function using numerical analysis

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Fig. 7. Seepage analysis result(Slope hight H=15m, Case3)

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Fig. 8. Comparison of safety factors by rainfall duration(H=10m)

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Fig. 9. Comparison of safety factors by rainfall duration(H=15m)

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Fig. 10. Comparison of safety factors by rainfall duration(H=20m)

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Fig. 11. Comparison of safety factors by rainfall duration(H=25m)

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Fig. 2. Rainfall conditions on US Army Corps of Engineers

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Fig. 4. Rainfall conditions on Huff`s 4/4 method

Table 1. Application method of rainfall event condition

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Table 2. Soil properties of granite weathered soil applied to slope stability analysis

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Table 3. Comparison of maximum groundwater level by each location according to rainfall condition

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Table 4. Safety factor of slope according to rainfall condition

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References

  1. Brand, E.W., Phillipson, H.B, (1984), "Relationship between Rainfall and Landslides in Hong Kong", Proceedings of the Forth International Symposium on Landslides, Toronto, Vol.1.
  2. Cho, Sung-Eun, Lee, Seung-Rae(2000), "Slope Stability Analysis of Unsaturated Soil Slopes Due to Rainfall Infiltration", Journal of the Korean Geotechnical Society, Vol.16, No.1, pp.51-64.
  3. Fredlund, D. G. and Xing, A.(1994,a), "Equation for the Soil-Water Characteristic Curve", Canadian Geotechnical Journal, Vol.31, pp.521-532. https://doi.org/10.1139/t94-061
  4. Fredlund, D. G., Xing, A. and Huang, S.(1994,b), "Predicting the Permeability Function for Unsaturated Soils using the Soil-Water Characteristic Curve", Canadian Geotechnical Journal, Vol.31, pp.533-546. https://doi.org/10.1139/t94-062
  5. Hong, Won-Pyo, Kim, Sang-Kyu, Kim, Maria, Kim, Yeon-Won, Han, Jung-Geun(1990), "Prediction of Rainfall-triggered Landslides in Korea", Journal of the Engineering Geology, Vol.6, No.2, pp.53-63.
  6. Kim, S. G. and Kim, Y. M. (1991), "Slope Instability due to Rainfall", Journal of the Korean Geotechnical Society, Vol.7, No.1, pp.53-64.
  7. Kim, Young-Nam, Chae, Yong-Su, Lee, Kang-Il(2013), "Experimental Study of Down-Scaled Model Slope on the Variation of the Ground Water Level of Drainable Soil Nailing, Journal of the Korean Geosynthetics Society, Vol.12, No.1, pp.39-50. https://doi.org/10.12814/jkgss.2013.12.1.039
  8. Lumb P.(1975), "Slope Failures in Hong Kong", Quartly Journal of Engineering Geology, Vol.8, pp.31-65. https://doi.org/10.1144/GSL.QJEG.1975.008.01.02
  9. Nilson, T. H., and Tumor, B. L.,(1975), "Influence of Rainfall and Ancient Landslide Deposit on Recent Landslides(1959-1971) in Urban Area of Contra Costa County", Col USGS Bull., 1388, pp.1-18
  10. Ryu, Chi-Hyob(1997), " Characteristics of Permeability and Shear Strength of Unsaturated Weathered Granite Soils, Ph.D Thesis, Dan-Kuk University, pp.205.
  11. Yagi, N. and Yatabe, R. (1987), "Prediction Method of Slope Failure in Sandy Soil due to Rainfall", Proc., 8th Asian Regional Conf., Soil Mechnics and Foundation Engineering, 1, pp.217-220