Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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A Combined Method for Rainfall-induced Landslides and Debris Flows in Regional-scale Areas

광역적 산사태-토석류 연계해석기법 제안

  • 홍문현 (연세대학교 건설환경공학과) ;
  • 정상섬 (연세대학교 건설환경공학과)
  • Received : 2019.07.19
  • Accepted : 2019.09.20
  • Published : 2019.10.31
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Abstract

This study describes a prediction method for rainfall-induced landslides and subsequently debris flows in a regional scale areas. Special attention is given to the calculation of the propagation of debris flows by considering rainfall infiltration into soil slopes and soil entrainments by debris flows. The proposed method was verified by comparing the analytical results and the measured ones reported by the previous research. As a result, predictions and observations were quite similar in terms of the front position, the velocity, volume and momentum of debris flows. Even when applied to natural mountain slope with complicated terrain, numerical results and observations were similar. At last, the combined analysis of landslides and debris flows were conducted. The landslides prediction showed a predictive rate of about 83%, and the result of the final volume of debris flow showed an error rate of 3%. As a result, the proposed combined method for landslides and debris flows overcomes the problem of separating the landslides analysis and the debris flows simulation. Especially, the proposed method can analyze the effects of rainfall on entrainments by debris flows as well as rainfall-induced landslides and the behavior of debris flows.

본 연구에서는 강우로 인한 산사태와 토석류의 거동분석을 위한 연계해석기법이 제안되었다. 산사태 발생 위치 및 체적을 토석류의 초기 발생 위치 및 체적 조건으로 사용하고 강우-침투에 의해 형성된 습윤대에 의해 정의되는 하부 지반의 습윤 조건이 토석류에 의한 연행침식작용 분석에서 고려되어 강우-침투, 산사태, 토석류에 이르는 일련의 과정에 대하여 일관된 해석이 수행될 수 있도록 구성되었다. 본 연계해석기법은 지리정보시스템을 기반으로 광역적 분석이 가능하도록 구성되었다. 본 연계해석기법을 활용한 해석 결과와 기존 연구자들에 의해 보고된 관측 결과를 비교하여 해석기법에 대한 검증 및 적용성을 확인하였다. 그 결과 시간에 따른 토석류 전방 위치 및 토석류의 속도, 체적, 운동량 측면에서 해석과 실험 결과가 서로 유사하게 나타났으며, 복잡한 지형을 갖는 자연사면에 적용한 경우에도 해석결과와 관측 결과가 유사하게 나타나 합리적인 예측결과를 도출하였다. 최종적으로 강우에 의한 산사태-토석류 연계해석 결과를 관측값과 비교한 결과, 산사태 해석은 약 83%의 예측률을 보였으며, 토석류의 최종 체적은 관측값과의 오차가 관측값의 약 3%($871m^3$)로 매우 작게 나타났다. 본 연구에서 제안된 산사태-토석류 연계해석기법은 기존의 산사태와 토석류 흐름을 분리해서 분석하는 문제를 극복하였으며, 특히 강우에 의한 산사태뿐만 아니라 토석류에 의한 연행침식작용에 대한 강우의 영향을 분석할 수 있다.

Keywords

References

  1. Bartelt, P., Buehler, Y., Christen, M., Deubelbeiss, Y., Graf, C., McArdell, B., ... and Schneider, M. (2013), "RAMMS_User Manual v1. 5 Debris Flow. A numerical model for debris flows in research and practice."
  2. Baum, R. L., Savage, W. Z., and Godt, J. W. (2002), "TRIGRS:a Fortran program for transient rainfall infiltration and grid-based regional slope-stability analysis", US geological survey open-file report, Vol.424, pp.38.
  3. Cho, S. E. and Lee, S. R. (2002), "Evaluation of Surficial Stability for Homogeneous Slopes Considering Rainfall Characteristics", Journal of Geotechnical and Geoenvironmental Engineering, Vol.128(9), pp.756-763. https://doi.org/10.1061/(ASCE)1090-0241(2002)128:9(756)
  4. Crosta, G. B., Cucchiaro, S., and Frattini, P. (2003), "Validation of semi-empirical relationships for the definition of debris-flow behavior in granular materials", In Proceedings of the Third International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment, Davos, Switzerland. Millpress, Rotterdam, pp.821-831.
  5. D'Ambrosio, D., Gregorio, S. D., and Iovine, G. (2003), "Simulating Debris Flows through a Hexagonal Cellular Automata Model: Sciddica s 3-hex", Natural Hazards and Earth System Sciences, Vol.3(6), pp.545-559. https://doi.org/10.5194/nhess-3-545-2003
  6. Gavin, K. and Xue, J. (2008), "A Simple Method to Analyze Infiltration into Unsaturated Soil Slopes", Computers and Geotechnics, Vol.35(2), pp.223-230. https://doi.org/10.1016/j.compgeo.2007.04.002
  7. Hong, M. H., Kim, J. H., Jung, G. J., and Jeong, S. S. (2016), "Rainfall Threshold (ID Curve) for Landslide Initiation and Prediction Considering Antecedent Rainfall", Journal of the Korean Geotechnical Society, Vol.32(4), pp.15-27. https://doi.org/10.7843/kgs.2016.32.4.15
  8. Hong, M., Kim, J., and Jeong, S. (2018), "Rainfall Intensityduration Thresholds for Landslide Prediction in South Korea by Considering the Effects of Antecedent Rainfall", Landslides, Vol. 15(3), pp.523-534. https://doi.org/10.1007/s10346-017-0892-x
  9. Iverson, R. M. (1997), "The physics of debris flows", Reviews of geophysics, Vol.35(3), pp.245-296. https://doi.org/10.1029/97RG00426
  10. Iverson, R. M., Reid, M. E., Logan, M., LaHusen, R. G., Godt, J. W., and Griswold, J. P. (2011), "Positive Feedback and Momentum Growth during Debris-flow Entrainment of Wet Bed Sediment", Nature Geoscience, Vol.4(2), pp.116. https://doi.org/10.1038/ngeo1040
  11. Jakob, M. and Friele, P. (2010), "Frequency and Magnitude of Debris Flows on Cheekye River, British Columbia", Geomorphology, Vol.114(3), pp.382-395. https://doi.org/10.1016/j.geomorph.2009.08.013
  12. Jeong, S., Kassim, A., Hong, M., and Saadatkhah, N. (2018), "Susceptibility Assessments of Landslides in Hulu Kelang Area Using a Geographic Information System-Based Prediction Model", Sustainability, Vol.10(8), pp.2941. https://doi.org/10.3390/su10082941
  13. Jeong, S., Kim, Y., Lee, J. K., and Kim, J. (2015), "The 27 July 2011 Debris Flows at Umyeonsan, Seoul, Korea", Landslides, Vol. 12(4), pp.799-813. https://doi.org/10.1007/s10346-015-0595-0
  14. Kim, J., Kim, Y., Jeong, S., and Hong, M. (2017), "Rainfall-induced landslides by deficit field matric suction in unsaturated soil slopes", Environmental Earth Sciences, Vol.76(23), pp.808. https://doi.org/10.1007/s12665-017-7127-2
  15. Kim, J., Lee, K., Jeong, S., and Kim, G. (2014), "GIS-based Prediction Method of Landslide Susceptibility Using a Rainfall Infiltration-groundwater Flow Model", Engineering Geology, Vol. 182, pp.63-78. https://doi.org/10.1016/j.enggeo.2014.09.001
  16. Kwan, J. S. H. (2012), "Supplementary technical guidance on design of rigid debris-resisting barriers", Geotechnical Engineering Office, HKSAR. GEO Report, No.270.
  17. Kwan, J. S. and Sun, H. W. (2006), "An Improved Landslide Mobility Model", Canadian Geotechnical Journal, Vol.43(5), pp. 531-539. https://doi.org/10.1139/t06-010
  18. Major, J. J. and Pierson, T. C. (1992), "Debris flow rheology: Experimental analysis of fine-grained slurries", Water Resources Research, Vol.28(3), pp.841-857. https://doi.org/10.1029/91WR02834
  19. McDougall, S., Boultbee, N., Hungr, O., Stead, D., and Schwab, J. W. (2006), "The Zymoetz River landslide, British Columbia, Canada: Description and Dynamic Analysis of a Rock Slide-debris Flow", Landslides, Vol.3(3), pp.195. https://doi.org/10.1007/s10346-006-0042-3
  20. Mein, R. G. and Larson, C. L. (1973), "Modeling infiltration during a steady rain", Water Resources Research, Vol.9(2), pp.384-394. https://doi.org/10.1029/WR009i002p00384
  21. Miller, D. J. and Burnett, K. M. (2008), "A Probabilistic Model of Debris-flow Delivery to Stream Channels, Demonstrated for the Coast Range of Oregon, USA", Geomorphology, Vol.94(1-2), pp. 184-205. https://doi.org/10.1016/j.geomorph.2007.05.009
  22. Muntohar, A. S. and Liao, H. J. (2009), "Analysis of Rainfall-induced Infinite Slope Failure during Typhoon Using a Hydrologicalgeotechnical Model", Environmental Geology, Vol.56(6), pp.1145-1159. https://doi.org/10.1007/s00254-008-1215-2
  23. O'brien, J. S., Julien, P. Y., and Fullerton, W. T. (1993), "Two-Dimensional Water Flood and Mudflow Simulation", Journal of Hydraulic Engineering, Vol.119(2), pp.244-261. https://doi.org/10.1061/(ASCE)0733-9429(1993)119:2(244)
  24. Park, D. W., Lee, S. R., Vasu, N. N., Kang, S. H., and Park, J. Y. (2016), "Coupled Model for Simulation of Landslides and Debris Flows at Local Scale", Natural Hazards, Vol.81(3), pp. 1653-1682. https://doi.org/10.1007/s11069-016-2150-2
  25. Pierce, J. L., Meyer, G. A., and Jull, A. T. (2004), "Fire-induced Erosion and Millennial-scale Climate Change in Northern Ponderosa Pine Forests", Nature, Vol.432(7013), pp.87. https://doi.org/10.1038/nature03058
  26. Stoffel, M. and Beniston, M. (2006), "On the incidence of debris flows from the early Little Ice Age to a future greenhouse climate: a case study from the Swiss Alps", Geophysical Research Letters, Vol.33(16).
  27. Takahashi, T. and Das, D. K. (2014), "Debris flow: mechanics, prediction and countermeasures", CRC press.
  28. Wang, Y. (1993), Personal cummunication (Takahashi and Das, 2014).

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