冰碛湖溃决型泥石流演化过程试验研究

目的]分析冰湖溃决型泥石流演化过程中运动参数的变化特征,为冰湖溃决型泥石流的防治提供理论依据。方法]采用水槽试验,探讨冰碛湖溃决型泥石流形成和演化过程。结果]冰碛湖溃决泥石流属于典型的水力类泥石流;根据水沙两相流容重的变化,冰碛湖溃决型洪水演化为泥石流的过程可以概括为挟沙水流—泥石流—挟沙水流的演变,相对应的泥石流的粒径从粉砂到砾石,再到粉沙的变化过程;泥石流容重越大,一次泥石流过程中颗粒粒径越粗。从不同组次的试验结果来看,冰碛湖溃决泥石流粒径与其容重也存在正相关关系。结论]泥石流的运动和演化过程本质上取决于冰碛湖溃决型洪水功率和沟床堆积物的粒径特征。

Experimental Study on Evolution of Debris Flow Induced by Moraine Lake Outburst Floods

Objective] Studying the characteristics of motion and evolution parameters of debris flow induced by glacier lake outburst floods(GLOFs) in order to provide countermeasures for debris flows prevention of this type. Methods] Base on flume tests, the formation and evolution of debris flow due to moraine lake outburst floods were studied. Results] The debris flow evolved from GLOFs was attributed to hydraulic reasons, the forming process could be divided into 5 phases. According to unit weight of water-sediment flow, the evolution process of debris flow could be summarized by successive sediment-laden flow, debris flow, sediment-laden flow. Correspondingly, The grain sizes of debris flow evolved from silts to gravels, and to silts in sequence. The outcomes from different sets of the test also showed that the grain sizes of the debris flow positively correlated to the unit weigh of the debris flow. Conclusion] The motion processes of debris flow depend both on the hydraulic power of the GLOFs and on the grain sizes of bed materials.