帕隆藏布江特大型泥石流的成灾模式及防治对策——以扎木镇-古乡段为例

Hazard model and countermeasure to super-large debris-flow in Parlung River——Case study of the section from Zamu Town to Guxiang Gully

文章通过对雅鲁藏布江的Ⅰ级支流—帕隆藏布江扎木镇-古乡段辫状水系地貌的研究,认为其与两岸支谷发育的泥石流群有关。通过对位于该河段下游的古乡沟和上游的地质弄巴泥石流特征的重点剖析,发现了特大型泥石流发育的2个重要特征,即支谷上游冰蚀围谷中赋存大量巨厚古今冰碛物和支谷中游峡谷段大型崩塌滑坡坝溃决。提出了特大型泥石流的成灾模式,并以该成灾模式解释了2000年易贡巨型滑坡堵江事件。最后,提出了基于上述成灾模式的帕隆藏布江流域特大型泥石流灾害防治的原则和方法。

Sichuan-Tibet highway has been seriously destroyed and endangering by super-large debris flows. Based on the study of the plait river of the segment from Zamu town to Guxiang gully in Parlung River, the first branch of Yarlu River, it is believed that the plait river is related to the large debris-flow fans from the tributary gullies of Parlung River. Based on the analysis to the 1953 super-large debris flow of Guxiang Gully and the super-large ancient debris flow of Dizhinongba Gully, it is discovered that the development of super-large debris flows in the segment has two important and common characteristics. That is, the large amount and huge thick glacial tills in the glacial cirque, and large avalanche and landslide clam-breach in the middle canyon of the tributaries of the Parlung River. The model of super-large debris-flow hazards is put forwards, and it is utilized to interpret Yigong Super-large Landslide in 2000 which is larger than the debris flow of Guxiang Gully in 1953 in scale, in the end, the paper puts forwards the principles and methods of preventing and countermeasure the super-large debris flow hazards in Parlung River or along Sichuan-Tibet highway.