The influence of slurry viscosity on the resistance characteristics of debris flow

<p>The slurry viscosity has significant influence on the movement of debris flow by affecting the resistance characteristics of the debris flow. Slurry viscosity affects several dimensionless parameters that characterize the debris flow regime, such as Bagnold number, Darcy number, and Reynolds number. Slurry viscosity also affects dimensionless parameters that characterize the scale of the debris flow. Manning’s roughness coefficient is an important parameter to characterize the resistance of debris flow. However, the values ​​of these dimensionless parameters related to slurry viscosity in natural gullies and its influence on roughness coefficients are still unclear. Through the analysis of the observation data of Jiangjia Ravine debris flow in Dongchuan, Yunnan Province, China, this study studied the value range of dimensionless numbers related to slurry viscosity and the relationship between debris flow roughness coefficient and slurry viscosity. The results showed that the roughness coefficient of debris flow gradually increased with an increase in the slurry viscosity. Slurry viscosity enhanced resistance in the macroscopic sense. The calculation formula of roughness coefficient considering slurry viscosity improved the precision in calculating the roughness coefficient of debris flow with high slurry viscosity. The research results can provide a reference for choosing slurry viscosity in the small model tests, and provide new method for the calculation of debris flow roughness coefficient in engineering practice.</p>