Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Rheological Models for Describing Fine-laden Debris Flows: Grain-size Effect

세립토 위주의 토석류에 관한 유변학적 모델: 입자크기 효과

  • Received : 2011.04.29
  • Accepted : 2011.06.23
  • Published : 2011.06.30
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Abstract

This paper presents the applicability of rheological models for describing fine-laden debris flows and analyzes the flow characteristics as a function of grain size. Two types of soil samples were used: (1) clayey soils - Mediterranean Sea clays and (2) silty soils - iron ore tailings from Newfoundland, Canada. Clayey soil samples show a typical shear thinning behavior but silty soil samples exhibit the transition from shear thinning to the Bingham fluid as shear rate is increased. It may be due to the fact that the determination of yield stress and plastic viscosity is strongly dependent upon interstructrual interaction and strength evolution between soil particles. So grain size effect produces different flow curves. For modeling debris flows that are mainly composed of fine-grained sediments (<0.075 mm), we need the yield stress and plastic viscosity to mimic the flow patterns like shape of deposition, thickness, length of debris flow, and so on. These values correlate with the liquidity index. Thus one can estimate the debris flow mobility if one can measure the physical properties.

본 연구는 토석류의 유통성과 관련하여 세립토의 흐름특성, 유변학적 모델들의 적용가능성 및 액성상태 의존성 유변학적 특성들을 비교 분석하였다. 입자크기에 따른 유변학적 특성을 살펴보고자 점토질이 풍부한 지중해 해저점토와 실트질이 풍부한 캐나다 동부 뉴펀들랜드 와부시 호수에서 채취한 광미에 대한 물성특성을 분석하였다. 점토질이 풍부한 세립토의 경우 전형적인 전단담화(shear thinning) 거동을 보이는 반면, 실트질 광미의 경우는 전단담화와 Bingham 유체 거동을 함께 보인다. 후자의 경우, 전단변형률속도를 높임에 따라 Bingham 유체처럼 거동하였다. 이러한 현상학적 차이는 입자크기에 따른 유동특성곡선의 차이에서 기인한 것이다. 항복응력과 소성점도의 결정은 전단변형에 의한 유동 입자들의 구조적 변화와 응력상태와 관련되기 때문이다. 세립토(< 0.075mm)를 다량 함유한 토석류의 유동성을 역해석하고자 할 때, 퇴적형상(흐름 양상, 퇴적층의 모양, 두께 및 길이 등)은 항복응력과 소성점도에 의해 결정된다. 항복응력과 소성점도는 액성지수의 함수로 나타낼 수 있으므로, 토석류의 발생가능지역에서 액성상태에 따른 토석류의 유동성을 평가할 지표로 활용할 수 있다.

Keywords

References

  1. Barnes, H.A. (1999), "The yield stress-a review or '${\pi}{\alpha}{\nu}{\tau}$ ${\rho}{\epsilon}{\iota}$'- everything flows?", Journal of Non-Newtonian Fluid Mechanics, Vol.81, pp.133-178. https://doi.org/10.1016/S0377-0257(98)00094-9
  2. Coussot, P., Nguyen, G.D., Huynh, H.T., and Bonn, D. (2002), "Viscosity bifurcation in thixotropic, yielding fluids", J. Rheol., Vol.46, pp.573-589. https://doi.org/10.1122/1.1459447
  3. Coussot, P., and Piau, J.-M. (1994), "On the behavior of fine mud suspensions", Rheol. Acta., Vol.33, pp.175-184. https://doi.org/10.1007/BF00437302
  4. Coussot, P. (2007), The mechanics of yield stress fluids: similarities, specificities and open questions, 16thAustralasian Fluid Mech. Conf., Crown Plaza, Gold Coast, Australia, pp.54-58.
  5. Imran, J., Parker, G., Locat, J., and Lee, H. (2001), "1D numerical model of muddy subaqueous and subaerial debris flows", J. Hydr. Eng., Vol.127, pp.959-968. https://doi.org/10.1061/(ASCE)0733-9429(2001)127:11(959)
  6. Jeong, S.W. (2006), Influence of physico-chemical characteristics of fine-grained sediments on their rheological behavior, PhD Thesis, Laval University, Quebec, Canada.
  7. Jeong, S.W., Leroueil, S. and Locat, J. (2009), "Applicability of power law for describing the rheology of soils of different origins and characteristics", Can. Geotech. J., Vol.46, pp.1011-1023. https://doi.org/10.1139/T09-031
  8. Jeong, S.W., Locat, J., Leroueil, S., and Malet, J.-P. (2010), "Rheological properties of fine-grained sediments: the roles of texture and mineralogy", Can. Geotech. J., Vol.47, pp.1085-1100. https://doi.org/10.1139/T10-012
  9. Jeong, S.W. (2010), "Grain size dependent rheology on the mobility of debris flows", Geosciences J., Vol.14, pp.359-369. https://doi.org/10.1007/s12303-010-0036-y
  10. Lastras, G., Canals M., Urgeles R., Amblas D., Ivanov M., Droz L., Dennielou B., Fabres J., Schoolmeester, T., Akhmetzhanov, A., Orange, D., and Garcia-Garcia, A. (2007), "A walk down the Cap de Creus canyon, Northwestern Mediterranean Sea: Recent processes inferred from morphology and sediment bedforms", Mar. Geol., Vol.246, pp.176-192. https://doi.org/10.1016/j.margeo.2007.09.002
  11. Leroueil, S. (2006), The Isotache Approach. Where are we 50 years after its development by Professor Suklje? 2006 Prof. Suklje's Memorial Lecture, Proceedings of the XIII Danube-European Conference on Geotechnical Engineering, Ljubljana, Slovenia, 29-31 May 2006. Slovenian Geotechnical Society, Ljubljana, Slovenia, Vol.1, pp.55-88.
  12. Locat, J., and Demers, D. (1988), "Viscosity, yield stress, remoulded strength, and liquidity index relationships for sensitive clays", Can. Geotech. J., Vol.25, pp.709-806.
  13. Locat, J. (1997), "Normalized rheological behaviour of fine muds and their flow properties in a pseudoplastic regime", Proc. 1stInt. Conf. on Debris-Flow Hazards Mitigation, San Francisco, ASCE, New York, pp.260-269.
  14. Locat, J., Lee, H.J., Locat, P. and Imran, J. (2004), "Numerical analysis of the mobility of the Palos Verdes debris avalanche, California, and its implication for the generation of tsunamis", Mar. Geol., Vol.203, pp.269-280. https://doi.org/10.1016/S0025-3227(03)00310-4
  15. Locat, J., and Lee H.J. (2009), "Submarine Mass Movements and Their Consequences: An Overview", Sassa, K. and Canuti, P. (eds.), Landslides-Disaster Risk Reduction, Springer-Verlag, (ch. 6), pp. 115-142.
  16. Malet, J.P., Remaitre, A., Maquaire, O., Ancey, C., and Locat, J. (2003), "Flow susceptibility of heterogeneous marly formations. Implications for torrent hazard control in the Barcelonnette basin (Alpes-de-Haute-Provence, France)", Proceedings of the 3rd International Conference on Debris-Flow Hazards Mitigation, Rickenmann, D. and Chen, C.L. (eds.), Millpress, Rotterdam, pp.351-362.
  17. Papanastasiou, T.C. (1987), "Flows of materials with yield", J. Rheol., Vol.31, pp.385-404. https://doi.org/10.1122/1.549926
  18. Sansoucy, M., Locat, J., Lee, H., Orange, D., and Jeong, S.W. (2005), "Preliminary analysis of the geotechnical and rheological properties of Capde Creus sediments with some consideration on slope in stability issues", Joint EUROSTRATA FORM, Annual Meeting, Salamanca, 24-27 Oct., 2005.
  19. Turmel, D., Locat, J., Cauchon-Voyer, G., Lavoie, C., Simpkin, P., Parker, G., and Lauzière, P. (2010), "Morphodynamic and Slope Instability Observations at Wabush Lake, Labrador", Submarine Mass Movements and Their Consequences, Advances in Natural and Technological Hazards Research, 2010, Volume 28, II, pp.435-446.
  20. Torrance, J.K. (1987), "Shear resistance of remoulded soils by viscometric and fall-cone methods: a comparison for the Canadian sensitive marine clays", Can. Geotech. J., Vol.24, pp.318-322. https://doi.org/10.1139/t87-037

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