云南小江流域泥石流堆积扇研究

RESEARCH ON THE DEPOSITION FANS IN XIAOJIANG WATERSHED,YUNNAN PROVINCE

泥石流堆积扇是判别泥石流性质、发育阶段和危险度的重要依据。通过对小江流域泥石流堆积扇的调查和观测,阐述了泥右流堆积过程和扇形地形成模式,并对泥石流扇群横向、平面组合类型及变形方式进行了分析。研究结果表明:小江流域泥石流堆积扇发育典型,类型齐全,扇群组合复杂,且呈现一定的规律性。

Deposition fan of debris flow is an important indication to discriminate tile characteristics, development and risk extent of debris flows. The research on the deposition fans is also significant to understand debris flow process and plan countermeasures against the disasters. This article demonstrates the distribution of debris fans and catologs 13 the types of fans. The dynamic depo-sitional properties and formational model of confined and transit confined debris flows are generalized according to investigation and observations to some typical fans. The initial stage of fan in horizontal is similar to ellipse and the middle and later stage evolved to typical fans. Fans in Xiao-jiang Watershed grouped complicately but show some kind of law mat,for one riverbank,, there are apexs related, apex- wing related, wings related and depression broken four types ; for two banks,there are right opposited,skew opposited,four fans right opposited and two fans right oppo-sited. Transformations are usually occurred owing to the neotectonic activities in the ways of mosaic,superimposition,wing-mosaic and beadlike.