中文摘要：

泥石流扇形地是山地居民生产生活的重要场所,也是泥石流泛滥危害的场地。科学评估泥石流扇形地的危险性,对扇形地开发具有重要意义。本文以对小江流域大白泥沟为研究对象,通过野外实地调查与成灾分析,结合泥石流扇形地形态特征和泥石流危害频率两个要素,建立了以距扇顶距离、与扇主轴夹角和危害频率为变量的定量扇形地危险性分布模型。结果表明：（1）泥石流扇形地上距离泥石流出山口越远,与主流线夹角越大的位置,受泥石流危害越小。（2）本模型在大白泥沟应用的计算结果与现场勘察验证结论相吻合,表明评估模型比较合理。（3）该模型所涉及的参数——距扇顶的长度、与扇主轴的夹角、危害频率,均可通过GIS和遥感分析得到,简单实用,为泥石流扇形地危险性评估工作提供了一种原理简单、计算方便的新方法。

英文摘要：

In the mountainous areas it is quite common for people to settle on the stretch of alluvial fans consisted primarily of debris flow sedimentation, where specific settlements are highly vulnerable than other places in case of debris flow strike. A scientific risk assessment of the alluvial fan would be of great significance in the later commer- cial exploitation of the fan. Aimed to Dabaini Gully of Xiaojiang basin, Yunnan as a case study, this research com- pleted field surveys and performed an integrated analysis of disaster formations, and then two factors, the morpho- logical characteristics of debris flow alluvial fan with occurrence frequency of debris flow were combined to introduce a quantitative risk distribution model of the fan, which depended on three variable parameters, the distance from fan apex, the angle between fan＇s main axis and the occurrence frequency. Results confirmed： （1） Damages in- curred by debris flow strike lied in the relative position of the settlement to the debris flow gully. Settlements located at a site far from the gully mouth, or at a larger separation angle with the mainstream line of debris flow would be less danger; （2） The application of the model to Dabaini Gully verified that a fine agreement between the field ob- servation with the modeling was established, justifying the validation of the model ; （3） Involved parameters of the model referred to the distance from fan apex, the included angle from fan axis and occun＇ence frequency, where all those values can be readily acquired by remote sensing and GIS analysis. The work provided a simple and conven- ient calculation method for risk assessment of debris flow fan.