安徽省黟县“621”型泥石流特征及形成机制

Charactrerstics and formation mechanism of the "6.21" debris flow in Yi County, Anhui Province

在野外调查的基础上,通过对黟县北部地区(柯村、美溪、宏潭)泥石流灾害产生的特征、分布、危害及形成规律的研究分析,论述了黟县"6 21"型泥石流产生的地质环境条件及主要控制性因素。认为:区内山高坡陡,地势陡竣、河谷狭窄呈"V"字型,人类工程活动强烈,而且降雨集中、强度大,易产生控制面积小、历时短、强度大而且能激发泥石流产生的暴雨量("6 12"型降雨),是安徽省比较典型的泥石流灾害易发区。预测分析表明,黟县北部地区不仅具备泥石流产生的地形、构造及岩性条件,而且16条支沟内松散固体物质储量丰富(沟谷的松散固体物质储量一般均大于1 0×104m3 km2),泥石流的产生具备丰富的固体物源基础。同时,区内也是安徽省强降雨中心之一,暴雨或大暴雨均发生于每年的6月中旬,类似于2002年"6 21"型的大暴雨。产生周期约为10～15年一遇。因此,预测黟县北部地区16条支谷泥石流发生的频率为10～15年一遇。

Based on the analysis of the feature, distribution and harm of the debris flow in the northern part of Yi County (Kecun. Meixi and Hongtan), this paper introduced the debris flow happend on 21th June,2002s.The authors thought the northern part of Yi County is a typical susceptible area to debris flow where the geologic erosion is high, man activity is severe and torrential rain is concentrated.In this paper,the authors analyzed the formation conditions, basic characteristics, triggering factors,formation and evolution of the kind of debris flows which happened on June 21th. 2002s in Yixian, Anhui Prorince. Evaluated the slope stability of the debris flow gully and made a scientific prediction for the trend of the debris flow activity.