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Journal of Mountain Science

, Volume 7, Issue 4, pp 361–366 | Cite as

Initiation and development of water film by seepage

  • Xiaobing LuEmail author
  • Peng Cui
  • Kaiheng Hu
  • Xuhui Zhang
Article

Abstract

When water seeps upwards through a saturated soil layer, the soil layer may become instability and water films occur and develop. Water film serves as a natural sliding surface because of its very small friction. Accordingly, debris flow may happen. To investigate this phenomenon, a pseudo-three-phase media is presented first. Then discontinuity method is used to analyze the expansion velocity of water film. Finally, perturbation method is used to analyze the case that a water flow is forced to seep upwards through the soil layer while the movement of the skeleton may be neglected relative to that of water. The theoretical evolutions of pore pressure gradient, effective stress, water velocity, the porosity and the eroded fine grains are obtained. It can be seen clearly that with the erosion and re-deposited of fine grains, permeability at some positions in the soil layer becomes smaller and smaller and, the pore pressure gradient becomes bigger and bigger, while the effective stress becomes smaller and smaller. When the effective stress equals zero, e.f. liquefaction, the water film occurs. It is shown also that once a water film occurs, it will be expanded in a speed of (U)(t)/(1 − ɛ).

Keywords

Slope Seepage Debris flow Water film 

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Copyright information

© Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Xiaobing Lu
    • 1
    Email author
  • Peng Cui
    • 2
  • Kaiheng Hu
    • 2
  • Xuhui Zhang
    • 1
  1. 1.Institute of MechanicsChinese Academy of SciencesBeijingChina
  2. 2.Institute of Mountain Hazards & EnvironmentChinese Academy of SciencesChengduChina

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