洪水起动泥石流沟床物质形成泥石流的试验

以研究震后强震区泥石流起动的临界水力条件为目的,在实验室内模拟了洪水起动沟床物质形成泥石流的条件,对比前人研究的颗粒起动的临界水流速度条件后得出：泥石流形成时的颗粒起动条件介于少量起动和大量起动之间,临界起动概率为0.05,约为少量起动的2倍,大量起动的1/3；泥石流形成的临界流速随起动颗粒中值粒径的增加而增加,随沟床坡度的增加而减小；颗粒的不均匀系数越大,起动所需要的临界流速也越大；修正的泥沙起动和泥石流起动公式适用于较大的泥沙颗粒粒径和泥沙不均匀系数的泥沙起动条件.

Experiment on the Initiation of Debris Flow by Flood

were large landslides and rock falls in the debris flow gully in the earthquake area during Wen- chuan Earthquake. The initiation condition of debris flow was changed greatly. To find out the critical velocity of flood for initiating debris flow, experiments of critical hydraulic conditions for initiating particles and debris flows were conducted in the laboratory. The conclusions are that the critical condition of initiation of debris flow is between the conditions of initiation of a little particle and abundance particle. The probability of critical initi- ation is 0. 05, two times as much as the probability of initiation of a little particle, one third of initiation proba- bility of abundance particle. The critical velocity of initiation of particle and debris flow increases with the me- dian particle size and asymmetrical coefficient of sediment. It decreases with the bed slope. The revised equa- tion of initiating velocity of particle and debris flow can be used in the calculation of initiating velocity of coarse particle and large asymmetrical coefficient of sediment.