阵性泥石流的平均流速与加速效应

Average Velocity and Acceleration Effects of Intermittent Debris Flows

本文讨论了泥石流的定义和分类 ,分析了不同形式泥石流运动方程的结构特点 ,认为泥石流平均流速公式与曼宁公式结构相似。考虑了粗颗粒平均粒径、泥石流龙头泥位、体积比浓度、不稳定层厚度、泥面相对比降等因素对平均流速的影响 ,并用蒋家沟实测资料和实验室资料进行了验证。最后通过初步实验说明两阵泥石流迭加过程中出现超载孔隙水压力 ,孔隙水压力突然增加 ,且不能及时消散 ,减小了泥石流龙头的阻力 ,出现泥浆飞溅的加速运动。从而可以解释在缓坡 ( 5°～ 1 0°)上泥石流流速能够达到每秒十几米的成因。

In this paper,the authors discussed the definition and classification of debris flows, and studied the characteristics of different equation forms of debris flow motion. The authors considered that the average velocity formulas of debris flows accord with the Manning's formula.By using the annual observed data in Jiangjia channel,the authors analysed and verified the effect factors of the average velocity formulas of debris flows,such as the average coarse grain size, the concentration by volume, the thickness of unsteady layer,and relative gradient of slope,etc. Finally, the superimpose effect on the moving process of intermittent debris flows was diccussed.The authors pointed out that the supernormal pore water pressure between debris flows and underlay reduces resistance between debris flows and underlay,and accelerates debris flows,thereby the velocity of debris flows on mild slope can reach 15m/s.