Author(s): An-Ping Shu; Le Wang; Zhi-Dong Zhang
Linked Author(s):
Keywords: Non-homogeneous debris flow; Solid and liquid phases; Hydraulic energygradient; The critical diameter; Velocity expression
Abstract: Debris flow with a large amount of solid particles from clay or silt to boulder in the mountainous area of the west China frequently behaves characteristics of non-homogeneous flow. According to the principle of the minimum energy dissipation, a critical diameter between the coarse and fine particles in non-homogeneous flow was determined, and the coarse particles are regarded as solid phase with the more critical diameter, the fine particles with the diameter less critical diameter and water are composed of liquid phase. Based the concept of the critical diameter, non-homogeneous debris flow may be divided into solid and liquid two-phase flow. A new velocity expression for liquid phase flow may be derived from the modified manning's formula based on theoretical analysis and our experimental data. Furthermore, the velocity of solid phase flow has been established from the law of mass conservation of solid and liquid phases. It has been verified that that calculating value using the velocity formulas of solid and liquid two-phase flow is basically corresponding to the measured data from Jiangjia gully, Yunnan Province, China. There comes to some meaningful conclusions, for example velocity of solid phase is more than one of liquid phase due to the specific gravity higher than 2.234of debris flow, whereas velocity of solid phase is usually less than one of liquid phase. These results are very significant for both developing dynamical model for non-homogeneous debris flow and designing of control engineering for debris flow disasters.
Year: 2009