Journal of Mountain Science

, Volume 10, Issue 2, pp 233–238 | Cite as

Influence of fine sediment on the fluidity of debris flows

  • Norifumi Hotta
  • Takahiro Kaneko
  • Tomoyuki Iwata
  • Haruo Nishimoto
Article

Abstract

Debris flows include a great diversity of grain sizes with inherent features such as inverse grading, particle size segregation, and liquefaction of fine sediment. The liquefaction of fine sediment affects the fluidity of debris flows, although the behavior and influence of fine sediment in debris flows have not been examined sufficiently. This study used flume tests to detect the effect of fine sediment on the fluidity of laboratory debris flows consisting of particles with various diameters. From the experiments, the greatest sediment concentration and flow depth were observed in the debris flows mixed with fine sediment indicating increased flow resistance. The experimental friction coefficient was then compared with the theoretical friction coefficient derived by substituting the experimental values into the constitutive equations for debris flow. The theoretical friction coefficient was obtained from two models with different fine-sediment treatments: assuming that all of the fine sediments were solid particles or that the particles consisted of a fluid phase involving pore water liquefaction. From the comparison of the friction coefficients, a fully liquefaction state was detected for the fine particle mixture. When the mixing ratio and particle size of the fine sediment were different, some other cases were considered to be in a partially liquefied transition state. These results imply that the liquefaction of fine sediment in debris flows was induced not only by the geometric conditions such as particle sizes, but also by the flow conditions.

Keywords

Debris flow Fine sediment Friction coefficient Liquefaction Open channel Reynolds stress 

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References

  1. Arattano M, Franzi L (2004) Analysis of different water-sediment flow processes in a mountain torrent. Natural Hazard and Earth System Sciences 4: 783–791.CrossRefGoogle Scholar
  2. Egashira S, Ashida K, Yajima H, Takahama J (1989) Constitutive equations of debris flow. Annals of the Disaster Prevention Research Institute, Kyoto University 32(B-2): 487–501. (In Japanese with English summary)Google Scholar
  3. Egashira S, Miyamoto K, Itoh T (1997) Constitutive equations of debris flow and their applicability. In: Proceedings of the 1st International Conference on Debris-Flow Hazards Mitigation, San Francisco, California, US, 7–9 August 1997. pp 340–349.Google Scholar
  4. Hotta N, Miyamoto K (2008) Phase classification of laboratory debris flows over a rigid bed based on the relative flow depth and friction coefficients. International Journal of Erosion Control Engineering 1(2): 54–61.Google Scholar
  5. Hotta N (2012) Basal interstitial water pressure in laboratory debris flows over a rigid bed in an open channel. Natural Hazards and Earth System Sciences 12: 2499–2505.CrossRefGoogle Scholar
  6. Itoh T, Egashira S (1999) Comparative study of constitutive equations for debris flows. Journal of Hydroscience and Hydraulic Engineering 17(1): 59–71.Google Scholar
  7. Nishiguchi Y, Uchida T, Tamura K, Satofuka Y (2011) Prediction of run-out process for a debris flow triggered by a deep rapid landslide. In: Genevois R, et al. (eds.), Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment. Casa Editrice Universita La Sapienza, Roma. pp 477–485.Google Scholar
  8. Rickenmann D (1991) Hyperconcentrated flow and sediment transport at steep slopes. Journal of Hydraulic Engineering 117(11): 1419–1439.CrossRefGoogle Scholar
  9. Takahashi T (1977) A mechanism of occurrence of mud-debris flows and their characteristics in motion. Annals of the Disaster Prevention Research Institute, Kyoto University 20(B-2): 405–435. (In Japanese with English summary)Google Scholar
  10. Takahashi T, Kobayashi K (1993) Mechanics of the viscous type debris flow. Annals of the Disaster Prevention Research Institute, Kyoto University 36(B-2): 433–449. (In Japanese with English summary)Google Scholar
  11. Tsubaki T, Hashimoto H, Suetsugi T (1982) Grain stresses and flow properties of debris flows. In: Proceedings of the Japan Society of Civil Engineers 317: 79–91. (In Japanese)CrossRefGoogle Scholar

Copyright information

© Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Norifumi Hotta
    • 1
  • Takahiro Kaneko
    • 2
  • Tomoyuki Iwata
    • 3
  • Haruo Nishimoto
    • 1
  1. 1.Faculty of Life and Environmental SciencesUniversity of TsukubaIbarakiJapan
  2. 2.Faculty of AgricultureThe University of TokyoTokyoJapan
  3. 3.Graduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan

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