KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Run-out Modeling of Debris Flows in Mt. Umyeon using FLO-2D

FLO-2D 모형을 이용한 우면산 토석류 유동 수치모의

  • 김승은 (강릉원주대학교 토목공학과) ;
  • 백중철 (강릉원주대학교 토목공학과) ;
  • 김경석 (한국도로공사 도로교통연구원)
  • Received : 2012.12.28
  • Accepted : 2013.03.16
  • Published : 2013.05.30
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Abstract

Multiple debris flows occurred on July 27, 2012 in Mt. Umyeon, which resulted in 16 casualties and severe property demage. Accurate reproducing of the propagation and deposition of debris flow is essential for mitigating these disasters. Through applying FLO-2D model to these debris flows and comparing the results with field observations, we seek to evaluate the performance of the model and to analyse the rheological model parameters. Representative yield stress and dynamic viscosity back-calculated for the debris flows in the northern side of Mt. Umyeon are 1022 Pa and 652 $Pa{\cdot}s$, respectively. Numerical results obtained using these parameters reveal that deposition areas of debris flows in Raemian and Shindong-A regions are well reproduced in 63-85% agreement with the field observations. However, the propagation velocities of the flows are significantly underestimated, which is attributable to the inherent limitations of the model that can't take the entrainment of bed material and surface water into account. The debris flow deposition computed in Hyeongchon region where the entrainment is not significant appears to be in very good agreement with the field observation. The sensitivity study of the numerical results on model parameters shows that both sediment volume concentration and roughness coefficient significantly affect the flow thickness and velocity, which underscores the importance of careful selection of these model parameters in FLO-2D modeling.

2011년 7월 27일 우면산 유역에서 일련의 토석류가 발생하여 많은 인명과 재산 피해를 야기했다. 이러한 토석류 피해를 저감하기 위해서는 토석류가 어떻게 이동하고 퇴적되어 하류부에 피해를 주는지를 예측할 수 있는 기술이 필요하다. 이 연구에서는 우면산 토석류에 대해서 FLO-2D 수치모형을 적용하여, 모형의 성능을 평가하고, 이들 토석류의 유동 매개변수를 분석하였다. 우면산 북측사면에서 발생한 토석류의 현장 관측자료와 FLO-2D 모의 결과 분석을 통해서 역산된 우면산 토석류의 대표 항복응력은 1,022 Pa 그리고 대표 동점성은 652 $Pa{\cdot}s$ 인 것으로 나타났다. 선정된 매개변수를 이용하여 우면산 토석류의 퇴적영역을 산정한 결과, 래미안 유역의 경우 63 - 85% 정확도의 피해유역을 재현됨으로서 FLO-2D 모형은 피해유역 산정에 적합한 것으로 나타났다. 하지만, FLO-2D 모형이 침식물질과 우수의 연행작용을 고려할 수 없는 고유의 한계 때문에 연행작용이 현저한 래미안 및 신동아 유역 토석류의 유하속도는 과소평가하는 것으로 나타났다. 유하부에서 침식에 의한 연행작용이 활발하지 않은 형촌마을 유역 토석류는 수로와 저수지 상부 부근에서의 퇴적을 우수한 정확도로 모의되었다. 민감도 분석 결과 유사체적농도와 바닥조도계수 모두 토석류의 흐름두께와 유속 모두에 상당한 영향을 미치는 것으로 나났으므로, 이들 매개변수의 선정에 신중해야 함을 보여주었다.

Keywords

References

  1. Bagnold, R. A. (1954). "Experiments on a gravity-free dispersion of large solid spheres in a Newtonian fluid under shear." Proc. of the Royal Soc. of London, 225, pp. 49-63. https://doi.org/10.1098/rspa.1954.0186
  2. Bertolo P. and Wieczorek, G. F. (2005). "Calibration of numerical models for small debris flows in Yosemite Valley, California, USA." Natural Hazard and Earth System Sciences, 5, pp. 993-1001. https://doi.org/10.5194/nhess-5-993-2005
  3. Cetina, M., Rajar, R., Hojnik, T., Zakrajsek, M., Krzyk, M., and Mikos, M. (2006). "Case study: Numerical Simulations of Debris Flow Below Stoze, Slovenia." J. Hydraulic Engineering, ASCE, Vol. 132, No. 2, pp. 121-130. https://doi.org/10.1061/(ASCE)0733-9429(2006)132:2(121)
  4. FLO-2D (2009). FLO-2D: Reference manual, 2009, available at: http://www.flo-2d.com/wp-content/uploads/FLO-2D-Reference- Manual-2009.pdf.
  5. Hsu, S. M., Chiou, L. B., Lin, G. F., Chao, C. H., Wen, H. Y. and Ku, C. Y. (2010). "Applications of simulation technique on debirs- flow hazard zone delineation: a case study in Hualien County, Taiwan." Natrual Hazards and Earth System Sciences, Vol 10, pp. 535-545. https://doi.org/10.5194/nhess-10-535-2010
  6. Iverson R. M., Reid, M. E., Logan, M., LaHusen, R. G., Godt, J. W. and Griswold, J. P. (2011). "Positive feedback and momentum grouth during debirs-flow entrainment of wet bed sediment." Nature Geoscience, Vol. 4, pp. 116-121. https://doi.org/10.1038/ngeo1040
  7. Julien, P. Y. and O'Brien, J. S. (1997). "Selected notes on debris flow dynamics, Recent developments on debris flows." Lecture note in earth sciences, Springer, Berlin, pp. 144-162.
  8. Kim, K.-S. (2008). "Characterisitcs of basin topography and rainfall triggering debris flow." J. of Korean Society of Civil Engineers, Vol. 28, No. 5, pp. 263-271 (in Korean).
  9. Korean Geotechnical Society (2011). Final report of investigation of the cause and preparation of countermeasures for landslides in Mt. Umyeon, Report No. KGS11-250, The Seoul Metropolis (in Korean).
  10. Li, M.-H., Sung, R.-T., Dong, J.-J., Lee, C.-T. and Chen, C.-C. (2011). "The formation and breaching of a short-lived landslide dam at Hsiaolin Village, Taiwan - Part II: Simulation of Debris Flow with Landslide Dam Breach." Engineering Geology, Vol. 123, pp. 60-71. https://doi.org/10.1016/j.enggeo.2011.05.002
  11. Lin, M.-L., Wang, K.-L. and Huang, J.-J. (2005). "Debris flow runoff simulation and verification - case study of Chen-You-Lan Watershed, Taiwan." Natural Hazards and Earth System Sciences, Vol. 5, pp. 439-445. https://doi.org/10.5194/nhess-5-439-2005
  12. Lin, P.-S., Lee, J.-H. and Chang, C.. W. (2011). "An application of the FLO-2D model to debris-flow simulation - A case of SONG-HER district in TAIWAN." Proc. of 5th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment, pp. 947-956.
  13. Luna, B. Q., Blahut, J., van Westen, C. J., Sterlacchini, S., van Asch, T. W. J., Akbas, S. O. (2011). "The application of numerical debris flow modelling for the generation of physical vulnerability curves." Natural Hazards and Earth System Sciences, Vol. 11, pp. 2047-2060. https://doi.org/10.5194/nhess-11-2047-2011
  14. Mikos, M., Fazarinc, R., Majes, B,. Rajar, .R, Zagar, D., Krzyk, M., Hojnik, T. and Cetina, M. (2006). "Numerical simulation of debris flows triggered from the strug rock fall source area, W Slovenia." Natural Hazards and Earth System Sciences, Vol. 6, pp. 261-270. https://doi.org/10.5194/nhess-6-261-2006
  15. O'Brien, J. S. & Julien, P. Y. (1998). "Laboratory analysis of Mudflow properties." Journal of Hydraulics Engineering, Vol. 114, No. 8, pp. 877-887.
  16. Paik, J. (2011). "Run-out analysis of debris flows on July 2011 in Mt. Umyeon." Proc. of 37 th Annual Conference of Korean Society of Civil Engineers, KINTEX, Goyang-si, Korea (in Korean).
  17. Pierson, T. C. & Costa, J. E. (1987). "A rheologic classification of subaerial sediment-water flows, in Debris Flows/Avalanches: Process, Recognition, and Mitigation." Rev. Eng. Geol., Vol. 7, edited by J. E. Costa and G. F. Wieczorek, Geol. Soc. of Am. Boulder, Colo, pp. 1-2. https://doi.org/10.1130/REG7-p1
  18. RD-FLOW (2011). "Characteristics of 2011 Korean Landslide and Debris Flow Disasters, River and Road in Mountain Area." Research Center for River Flow Impingement and Debris Flow, Vol. 4, Special Issue, Gangneung, Korea (in Korean).
  19. Son, S.-H., Choi, B. and Paik, J. (2012). "Characterisitics of rainfall and groundwater level in Mt. Umyeon." Proc of 38 th Annual Conference of Korean Society of Civil Engineers, pp. 769-772 (in Korean).
  20. Takahashi, T. (2007). Debris flow: Mechanics, Prediction and Countermeasures, Taylor & Francis Group, London, UK.

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