基于流速衰减特征的泥石流冲出距离预测方法

泥石流冲出距离的确定是泥石流灾害评价及防治中的关键环节。基于泥石流在堆积区流速的变化特征,提出了泥石流流速"衰减系数"的概念。通过对泥石流流速衰减系数的定义和计算公式的推导,提出了一种基于泥石流流速衰减系数来确定泥石流冲出距离的新方法,并以四川省泸定县干沟泥石流为实例进行计算和验证。研究结果表明:当干沟泥石流在堆积区的流速大于初始(沟口)流速的15%时,流速的衰减程度极为显著;而当堆积区流速小于初始速度的15%时,流速的衰减极为缓慢。研究结果对泥石流灾害的危险性评价及防灾减灾具有一定的理论和实践意义。

Debris Flow Run Out Distance Prediction Based on the Velocity Decreasing Coefficient

The prediction of debris-flow rum out distance is crucial to it’s hazards assessment and mitigation planning.Based on the phenomenon of debris flow velocity decreasing in inundate area,this paper give the general idea of attenuation coefficient.After the definition interpreting and the formula constructing of attenuation coefficient,this paper put forward a method to debris flow run out distance prediction based on the definition of velocity attenuation coefficient.Finally,take Gangou debris flow which locate in Luding country(Sichuan province) as an example to calculating it’s run out distance.The result show that when the velocity of debris flow is higher than 15% of beginning velocity,the decreasing degree of debris flow velocity is obvious,and when the velocity of debris flow is lower than 15% of beginning velocity,the decreasing degree of debris flow velocity is slow.This research is significance to debris flow hazards assessment and mitigation.