DOI QR코드

DOI QR Code

수위급강하에 대한 제방 사면의 취약도 곡선 작성

Development of Fragility Curves for Slope Stability of Levee under Rapid Drawdown

  • 조성은 (한경국립대학교 건설환경공학부 )
  • Cho, Sung-Eun (School of Civil and Environmental Engrg. & Construction Engrg. Research Institute, Hankyong National Univ.)
  • 투고 : 2023.08.18
  • 심사 : 2023.09.15
  • 발행 : 2023.10.31

초록

극한홍수에 대응하기 위한 홍수 위험도 관리의 필수 요소인 홍수 위험도 평가를 위해서는 댐 및 하천제방과 같은 홍수방어시설에 대하여 여러 파괴 메커니즘을 고려한 신뢰도 해석을 수행해야 한다. 본 연구에서는 수위급강하에 의한 제체 사면의 시간에 따른 확률론적 안정성 평가에 대하여 연구하였다. 유한요소 해석에 의한 침투해석 결과를 사면안정 해석에 연동하여 Monte Carlo Simulation을 수행함으로써 수위급강하에 따른 제체의 시간의존적 거동을 연구하고 파괴확률을 계산하여 제방의 취약도 곡선을 작성하였다. 수위급강하에 의한 사면의 파괴확률은 특정 수위까지는 매우 작은 값을 유지하지만, 그 이상에서는 수위가 증가함에 따라 급격하게 증가하는 현상을 보였다. 또한 취약도 곡선은 수위 하강 속도에 크게 영향을 받았다. 수위 저하 속도는 수문 시나리오에 의한 수위의 변동해석을 통하여 결정되므로 수위급강하에 따른 제방 제외지 사면의 안정성은 기후변화에 따라 크게 영향을 받을 것으로 판단된다.

To effectively manage flood risk, it is crucial to assess the stability of flood defense structures like levees under extreme flood conditions. This study focuses on the time-dependent probabilistic assessment of embankment slope stability when subjected to rapid water level drops. We integrate seepage analysis results from finite element analysis with slope stability analysis and employ Monte Carlo simulations to investigate the time-dependent behavior of the slope during rapid drawdown. The resulting probability of failure is used to develop fragility curves for the levee slope. Notably, the probability of slope failure remains low up to a specific water level, sharply increasing beyond that threshold. Furthermore, the fragility curves are strongly influenced by the rate of drawdown, which is determined through hydraulic analysis based on flood scenarios. Climate change has a significant impact on the stability of the water-side slope of the embankment due to water level fluctuations.

키워드

과제정보

이 성과는 정부(과학기술정보통신부)의 재원으로 한국연구재단의 지원을 받아 수행된 연구임(NRF-2022R1F1A1062669).

참고문헌

  1. Baecher, G. B. and Christian, J. T. (2003), Reliability and statistics in geotechnical engineering, Wiley, New York. 
  2. Cho, S. E. (2007), "Effects of Spatial Variability of Soil Properties on Slope Stability", Engineering Geology, Vol.92, No.3-4, pp.97-109.  https://doi.org/10.1016/j.enggeo.2007.03.006
  3. Cho, S. E. (2021), "Probabilistic Assessment of Seepage Stability of Soil Foundation under Water Retaining Structures by Fragility Curves", Journal of the Korean Geotechnical Society, Vol.37, No.10, pp.41-54 (in Korean).  https://doi.org/10.7843/KGS.2021.37.10.41
  4. Cho, S. E. (2022), "Applicability of Practical Reliability Analysis to Develop Fragility Curves for Levee", Journal of the Korean Geotechnical Society, Vol.38, No.11, pp.19-30 (in Korean).  https://doi.org/10.7843/KGS.2022.38.11.19
  5. Dawson, R. J., Hall, J., Sayers, P., Bates, P., and Rosu, C. (2005), "Sampling-Based Flood Risk Analysis for Fluvial Dike Systems", Stochastic Environmental Research and Risk Assessment, Vol.19, No.6, pp.388-402.  https://doi.org/10.1007/s00477-005-0010-9
  6. Fenton, G. A. and Griffiths, D. V. (1997), "Extreme Hydraulic Gradient Statistics in Stochastic Earth Dam", Journal of Geotechnical and Geoenvironmental Engineering, Vol.123, No.11, pp.995-1000.  https://doi.org/10.1061/(ASCE)1090-0241(1997)123:11(995)
  7. Griffiths, D. V. and Fenton, G. A. (1998), "Probabilistic Analysis of Exit Gradients due to Steady Seepage", Journal of Geotechnical and Geoenvironmental Engineering, Vol.124, No.9, pp.789-797.  https://doi.org/10.1061/(ASCE)1090-0241(1998)124:9(789)
  8. Guardiani, C., Soranzo, E., and Wu, W. (2022), "Time-Dependent Reliability Analysis of Unsaturated Slopes under Rapid Drawdown with Intelligent Surrogate Models", Acta Geotechnica, Vol.17, pp.1071-1096.  https://doi.org/10.1007/s11440-021-01364-w
  9. Isukapalli, S. S., Ro y, A., and Georgopoulos, P. G. (2000), "Efficient Sensitivity/Uncertainty Analysis Using the Combined Stochastic Response Surface Method and the Automated Differentiation: Application to Environmental and Biological Systems", Risk Analysis, Vol.20, No.5, pp.591-601.  https://doi.org/10.1111/0272-4332.205054
  10. Kim, J. M., Kim, J. S., Oh, E. Ho., and Cho, W. B. (2014), "Numerical Anlysis of Hydrograph Determination for Cohesive Soil Levee", Journal of the Korean Geotechnical Society, Vol.30, No.4, pp.81-92 (in Korean).  https://doi.org/10.7843/KGS.2014.30.4.81
  11. Lane, P. A. and Griffiths, D. V. (2000), "Assessment of Stability of Slopes under Drawdown Conditions", Journal of Geotechnical and Geoenvironmental Engineering, Vol.126, No.5, pp.443-450.  https://doi.org/10.1061/(ASCE)1090-0241(2000)126:5(443)
  12. Leong, E. C. and Rahardjo, H. (1997), "Permeability Functions for Unsaturated Soils", Journal of Geotechnical and Geoenvironmental Engineering, Vol.123, No.12, pp.1118-1126.  https://doi.org/10.1061/(ASCE)1090-0241(1997)123:12(1118)
  13. Li, D., Chen, Y., Lu, W., and Zhou, C. (2011), "Stochastic Response Surface Method for Reliability Analysis of Rock Slopes Involving Correlated Non-normal Variables", Computers and Geotechnics, Vol.38, No.1, pp.58-68.  https://doi.org/10.1016/j.compgeo.2010.10.006
  14. Li, D., Li, L., Cheng, Y., Hu, J., Lu, S., Li, C., and Meng, K. (2022), "Reservoir Slope Reliability Analysis under Water Level Drawdown Considering Spatial Variability and Degradation of Soil Properties", Computers and Geotechnics, Vol.151, 104947. 
  15. Mainguenaud, F., Peyras, L., Khan, U. T., Carvajal, C., Sharma, J., and Beullac, B. (2023), "A Probabilistic Approach to Levee Reliability Based on Sliding, Backward Erosion and Overflowing Mechanisms: Application to An Inspired Canadian Case Study", Journal of Flood Risk Management, e12921. 
  16. Morgenstern, N. (1963), "Stability Charts for Earth Slopes During Rapid Drawdown", Geotechnique, Vol.13, No.2, pp.121-131.  https://doi.org/10.1680/geot.1963.13.2.121
  17. Pinyol, N. M., Alonso, E. E., and Olivella, S. (2008), "Rapid Drawdown in Slopes and Embankments", Water Resources Research, Vol.44, W00D03. 
  18. Porter, K. (2018), A Beginner's Guide to Fragility, Vulnerability, and Risk, University of Colorado Boulder, http://spot.colorado.edu/~porterka/Porter-beginners-guide.pdf 
  19. Rocscience (2022), Slide2 V9.0, Rocscience Inc, Toronto. 
  20. Rossi, N., Bacic, M., Kovacevic, M. S., and Libric, L. (2021), "Development of Fragility Curves for Piping and Slope Stability of River Levees", Water, Vol.13, No.5, 738. 
  21. Sharafati, A., Yaseen, Z. M., and Pezeshki, E. (2020), "Strategic Assessment of Dam Overtopping Reliability Using a Stochastic Process Approach", Journal of Hydrologic Engineering, Vol.25, No.7, 04020029. 
  22. Siacara, A. T., Beck, A. T., and Futai, M. M. (2020), "Reliability Analysis of Rapid Drawdown of an Earth Dam Using Direct Coupling", Computers and Geotechnics, Vol.118:103336. 
  23. USACE (1996), Risk-based Analysis for Flood Damage Reduction Studies, US Army Corps of Engineers, Engineer Manual 1110-2-1619. 
  24. Vorogushyn, S., Merz, B., and Apel, H. (2009), "Development of Dike Fragility Curves for Piping and Micro-instability Breach Mechanisms", Natural Hazards and Earth System Sciences, Vol.9, pp.1383-1401.  https://doi.org/10.5194/nhess-9-1383-2009
  25. Wojciechowska, K., Pleijter, G., Zethof, M., Havinga, F., Haaren, D. V., and Ter Horst, W. (2015), "Application of Fragility Curves in Operational Flood Risk Assessment", In 5th international symposium on geotechnical safety and risk (pp. 528-534). IOS Press. https://doi.org/10.3233/978-1-61499-580-7-528