白龙江流域泥石流活动趋势预测研究——以舟曲—武都角弓段为例

Trend Prediction of Debris Flow in Bailong River Basin

以白龙江流域21条典型泥石流沟为研究对象,将采用定性方法——集对分析法得出的评价结果作为泥石流当前活动性状态,与定量方法——地貌信息熵理论得出的评价结果进行比对,定性、定量相结合动态预测未来泥石流的活动趋势。结果表明:研究区除石阏子沟、化马沟、武都关沟、寨子沟4条泥石流沟属于中度易发,双沟属于极度易发外,其余16条泥石流沟均属于重度易发;除双沟、大沟头沟、百草坝沟、庙沟、河南大沟等5条泥石流沟处于幼年期地貌,红土湾沟、大沟里沟、拓石沟等3条泥石流沟处于壮年期地貌外,其余13条泥石流沟均处于壮年偏幼期地貌;在未来活动趋势会上升的有大沟头沟、百草坝沟、河南大沟等13条泥石流沟;当前活动等级为中度的大沟头沟、百草坝沟、河南大沟等3条泥石流沟属于高隐蔽性泥石流,在区域泥石流活动性评价时容易忽略其危险性;另外,从地貌信息熵值也可以初步判别该区域泥石流的活动性,以地貌信息熵界限值0.1,可大致将泥石流活动性划分为极度(≤0.1)、中度或重度(>0.1)2个等级。

Taking 21 typical debris flow gullies in Bailong River basin as objects of study,the paper used the evaluation results obtained by qualitative method( set pair analysis method) as the current activity state of debris flow to compare with the evaluation results obtained by quantitative method( geomorphic information entropy theory) and dynamically predicted the future tendency of debris flow activity by the qualitative and quantitative combination. The outcomes show that a) except the 4 gullies of Shiyanzi,Huama,Wuduguan and Zhaizi belonging to moderate occurrence and Shuanggou belonging to extremely easy to happen debris flow in the studied area,the remaining 16 gullies all belong to severe and easy to occur debris flow; b) except the 5 gullies of Shuanggou,Dagoutou,Baicaoba,Miaogou and He'nandagou in the juvenile geomorphology and 3 gullies of Hongtuwan,Dagouli and Tuoshi in the maturity geomorphology,the remaining13 gullies all belong to young maturity geomorphology; c) there 13 debris flow gullies,including Dagoutou,Baicaoba and He'nandagou have upward trend of activity in the future; d) the 3 gullies of Dagoutou,Baicaoba and He'nandagou that the current activity belonging to moderate belong to the ones of high concealment and the risk is easy to overlook when evaluate the regional debris flow activity and; e) in addition,we can preliminarily determine the activity of the regional debris flow from the geomorphologic information entropy value. Taking the geomorphologic information entropy threshold value as 0.1,it can roughly divide the debris flow susceptibility into two grades of extreme( ≤0.1) and moderate or severe( >0.1).