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

Korean Geo-Environmental Society (한국지반환경공학회)
권호 표지
DOI QR코드

DOI QR Code

The Study of Sediment Volume Concentration in Liquefied-Layer of Debris Flow

토석류 유동층에서 토사체적 농도 특성에 관한 연구

  • Kim, Sungduk (Department of Civil Engineering, Chung-Ang University)
  • Received : 2014.09.13
  • Accepted : 2014.11.04
  • Published : 2014.12.01
Download PDF
⟨ Previous Next ⟩

Abstract

The purpose of this study is to estimate the sediment volume concentration of the liquified-solid mixture which is included fine sediment fractions, according to the variance of the channel slope and the water supply. The numerical model was performed by using the Finite Differential Element Method (FDM) based on the equation for the mass conservation, momentum conservation and the equation of coarse sediment an fine sediment. In comparison of varying the channel slope, the deeper the channel slope, the inflection point of the sediment concentration was occurred rapidly. In comparison of variance of the water supply, as the water supply increases fluctuation with high sediment concentration. In this situation, debris flow changes to the turbulent flow and the sediment becomes to be floated. In comparison varying the length paved saturated sediment, the longer the length, the high concentration of sediment occurred, for the safety of the slope it is needed to check the possibility of the erosion in the slope by debris flow. The results of this study will provide useful information in predicting of the disaster by the liquified-solid mixture and in prevention of the debris flow with various the slope in the mountain side.

본 연구의 목적은 산지에서 세립사가 포함된 유동체 혼합물이 다양한 경사 각도를 갖는 수로에서 공급유량의 변화에 따른 토사체적농도를 분석한 것이다. 수치모델은 질량보존 및 운동량 보존에 관한 방정식 그리고 세립토와 조립토 방정식에 기초하여 유한차분법을 이용하여 수행되었다. 비탈 경사면 각도 변화에 따른 토사농도 비교에서 경사가 급할수록 토사체적 농도의 급격한 변곡점이 나타났다. 공급유량의 변화에서는 공급유량이 많을수록 Fluctuation이 발생하였고, 토석류의 상태가 난류형으로 변하여 토사가 부유사 형태로 변화되었다. 이는 토석류의 이동속도가 빠르게 됨을 알 수 있다. 포화된 조립토의 변화에 따른 비교에서는 그 길이가 길수록 고농도가 발생하였으므로 사면 안정을 위해서는 사면에서의 침식 가능 여부를 먼저 판단해야 된다. 본 연구의 결과는 강우 변화에 따른 비탈면 하류단에서의 유동체 혼합물의 토석류에 의한 재해를 예측 및 다양한 경사의 비탈면을 갖는 산지 밑에서의 토석류에 의한 재해에 대한 정보를 제공할 것이다. 또한 사면 안정 시 효율적인 사면 경사각도로 설치하는 것과 사면에서의 침식 방지등에 있어 토석류와의 관계성 분석 및 토석류 재해를 막기 위한 다양한 대책을 세우는 데 효과적인 정보를 제공할 것이다.

Keywords

References

  1. Armanini, A., Fraccarollo, L. and Rosatti, G. (2009), Twodimensional simulation of debris flows in erodible channels. Computers & Geosciences, Vol. 35, pp. 993-1006. https://doi.org/10.1016/j.cageo.2007.11.008
  2. Calligaris, C., Boniello, M. A. and Zini, L. (2008), Debris flow modeling in Julian Alps using FLO-2D, Monitoring, Simulation, Prevention and Remediation of Dense Debris Flows II, WIT, pp. 76-83.
  3. Chen, H., Dadson, S. and Chi, Y. G. (2006), Recent rainfallinduced landslides and debris flow in northern Taiwan, Geomorphology, Vol. 77, pp. 112-125. https://doi.org/10.1016/j.geomorph.2006.01.002
  4. Crosta, G. B. (2001), Failure and flow development of a complex slide: the 1993 Sesa, landslide, Engineering Geology, Vol. 53, pp. 173-199.
  5. Egashira, S., Miyamoto, K. and Itoh, T. (1997), Constitutive equation of debris flow and their applicability, 1st International ConferenceonDebris-Flow Hazards Mitigation, ASCE, pp. 340-349.
  6. Jun, B. H., Jun, K. W. and Lee, S. C. (2014), Analysis of the erosion/deposition in debris flow using terrestrial Lidar data, Koren Review of Crisis & Emergency Management, Vol. 10, No. 3, pp. 61-71 (in Korean).
  7. Kim, S. D., Oh, S. W. and Lee, H. J. (2013), The study of relationship between berm width and debris flow at the slope, Journal of the Korean Geoenvironmental Society, Vol. 14, No. 11, pp. 5-12 (in Korean). https://doi.org/10.14481/jkges.2013.14.12.005
  8. Kim, S. D., Yoon, I. R., Oh, S. W., Lee, H. J. and Bae, W. S. (2012), Numerical simulation for behavior of debris flow according to the variances of slope angle, Journal of the Korean Geoenvironmental Society, Vol. 13, No. 6, pp. 59-66 (in Korean).
  9. Martinez, C., Miralles-Wilhelm, F. and Garcia-Martinez, R. (2008), Verification of a 2D finite element debris flow model using Bingham and cross rheological formulations, Monitoring, Simulation, Prevention and Remediation of Dense Debris Flows II, WIT, pp. 56-64.
  10. McDougall, T., Donley, H. F. and Howard, T. R. (2003), On debris flow/avalanche California, in debris flows/avalanches: Process, Recognition and Mitigation, Reviews in Engineering Geology, Geol. Soc. AM. VII, pp. 223-236.
  11. Nakatani, K., Wada, T., Satofuka, Y. and Mizuyama, T. (2008), Development of "Kanko 2D (Ver. 2.00)", a user-friendly one-and two- dimensional debris flow simulator equipped with a graphical user interface, International Journal of Erosion Control Engineering, Vol. 1, No. 2, pp. 62-72. https://doi.org/10.13101/ijece.1.62
  12. O'Brien, J. S., Julien, P. Y. and Fullerton, W. T. (1993), Twodimensional water flood and mudflow simulation, Journal of Hydraulic Engineering, Vol. 119, No. 2, pp. 244-266. https://doi.org/10.1061/(ASCE)0733-9429(1993)119:2(244)
  13. Paik, J. C. and Park, S. D. (2009), Numerical modeling and field measurement of 1D debris flows, Poceeding of the Korean Society of Civil Engineers, pp. 695-698 (in Korean).
  14. Swantson, D. N. and Swantson, F. J. (1974), Timber harvesting, mass erosion, and steepland forest geomorphology in the Pacific Northwest. In: Geomorphology and Engineering. Edited by D.R. Coates. Dowden, Hutchinson, and Ross. Inc., Stroudsburg, pp. 199-221.
  15. Takahashi, T., Nakagawa, H., Harada, T. and Yamashiki, Y. (1992), Routing debris flows with particle segregation, Journal of Hydraulic Engineering, Vol. 118, No. 11, pp. 1490-1507. https://doi.org/10.1061/(ASCE)0733-9429(1992)118:11(1490)
  16. Takahashi, T. and Tsujimoto, H. (1984), Mechanics of granular flow in inclined chute. Journal of Hydraul. Coast. Environment Engineering, JSCE, Vol. 565, No.2-39, pp. 57-71 (in Japanese).
  17. Wang, N. S., Yi, R. H. and Liu, D. (2008), A solution method to the problem proposed by Wang in voting systems, Journal of Computational and Applied Mathematics, Vol. 221, pp. 106-113. https://doi.org/10.1016/j.cam.2007.10.006