Dynmic characteristics of debris flow based on the granularmetric analysis of the value of φ

The authors predicted the dynamic characteristics of the debris flow. First, the granularmetric analysis was carried out and the qualitative judgment of the sedimentary environment was recognized. Then the granularmetric analysis on the accumulation zone of the debris flow was accomplished with the graphic method and the preliminary judgment of the dynamic characteristics was described. Finally, the force balance equation of the grain during the debris motion process was setup. The features of the debris flow accumulation zone of Fangshanguo along the Jinshajiang river was analyzed and conclusions were come out: the debris flow is composed of the gravel generally and poor in sorting, it made with the use of pulling and rolling of the gravity slope. Base on it, the velocity of Fangshanguo gully was calculated as ub=8.67 m/s.