Mechanism of Debris Flows in Mountain Streams

Abstract:

This paper suggests the mechanism of occurrence of debris flow in mountain streams. It is found that the sliding of the undermined stream banks follows the exponential probability distribution function. This indicates that the major amount of debris is from an intensive sliding in the initial stage of flood flow development. This can be otherwise proved by the viscous flow boundary layer theory such as the shear stresses on the wall are initially very large. Through a relative dimensional analysis, a special dimensionless parameter K is grouped which has a very important effect on the occurrence of the acceleration of the heavy debris by the flow. It interprets, during the flood flow development, the amount of debris on the stream bed can only be accelerated when the kinetic energy of the flow is greater than the apparent work of the debris against the flow. Of course, as a transient behavior, once it starts, the sudden acceleration of a huge amount of debris flow bore will usually cause an unpredictable downstream disaster.

• Periodical: Applied Mechanics and Materials (Volume 419)
• Pages: 883-888
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.419.883
• Online since: October 2013
• Authors: Chang Huan Kou, Shih Wei Ma, Meng Wei Lai
• Keywords: Debris Flow, Debris Flow Bore, Dimensional Analysis, Mechanism, Stochastic Approach, Transient Behavior

References

[1] H. Rouse: Advanced Mechanics of Fluids, first ed., Wiley, New York (1959), p.340.

[2] Y. P Kou: Fluid dimensional analysis and tensor analysis, World Book, Taipei (1973).

[3] Y. P Kou, Y.F. Lin and A.P. Wang: Zhuoshui River Turbulence Qualities and River Management, First Hydraulic Engineering Conference (1982).