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冰碛补给型泥石流是发育在高海拔冰缘山区的一种特殊灾害地貌过程,以其物源“非粗化层”和不同粒径土体同时启动的特点区别于一般水力类泥石流。冰碛土作为该类泥石流主要的启动物源,具有储量丰富、集中分布、地貌部位高的特点。发育于贡嘎山东坡的小河子沟是典型的高地貌部位冰碛补给型泥石流,其物源汇集过程可分为以下3个阶段:沟道汇集阶段、土体粗化阶段和循环冻融阶段。这类泥石流的启动主要受前期持续降雨加短时强降雨激发,启动后具有放大效应显著、致灾能力强的特点。本文以小河子沟泥石流为例,提出了高地貌部位冰碛补给型泥石流的启动机制,研究成果将在此类泥石流防治及风险控制方面提供理论支撑。
The moraine recharge debris flow is a special disastrous geomorphology process developed in the ice edge mountain area of high altitude, which is distinguished from the general hydraulic debris flow by its source “non-coarsening layer ” and the simultaneous start-up of different particle size soils. As the main source of this kind of debris flow, moraine soil has the characteristics of abundant reserves, concentrated distribution and high landform. The Xiaohezi Gully, which is developed on the east slope of Gongga Mountain, is a typical moraine recharge debris flow with high geomorphology. The process of provenance pooling can be divided into the following three stages: trench collection stage, soil roughening stage and cyclic freeze-thaw stage . The start-up of such debris flow is mainly triggered by strong rainfall when the rainfall is shortened in the early period, which has the characteristics of significant amplification effect and strong disaster-causing ability after start-up. Taking Xiaohezi gully debris flow as an example, this paper puts forward the starting mechanism of moraine replenishment type debris flow in high geomorphological part. The research results will provide theoretical support for such debris flow prevention and risk control.