摘要
2011年贵州省望谟县打易镇的大范围浅层滑坡诱发的沟谷泥石流提供了研究这类泥石流地形和降雨条件的机会。在地质条件一致和小区域内的降雨条件基本一致的情况下,地形条件就是这些泥石流暴发与否的唯一决定因素。对比一些重要的地形因素与泥石流暴发的关系,得出了由流域面积、沟床纵比降和25°～45°山坡坡度面积比组成的泥石流综合地形因子T。在地形因子T的基础上,研究获得了由前期降雨量、1 h降雨强度、年平均降雨量等组成的降雨因子R。由地形因子T和降雨因子R获得的临界条件P可以判断该区域的泥石流暴发。由于研究工作部分基于泥石流的形成机理,研究成果还可用于其他区域的泥石流形成预测,为泥石流的预测预报提供了一个较好的方法。
The large number of debris flow events in the Dayi area,Guizhou,China,due to a large rainfall event in June 2011 provided a good opportunity to study the influence of topographical factors and rainfall factors on the triggering of debris flows by shallow landslides. The triggering mechanism for these debris flows is the transport of sediment provided by shallow landslides into the channel. During the heavy rainfall event in 2011,37 gully type debris flows caused by shallow landslides were triggered. In some catchments no such debris flows were triggered even though these catchments were in the vicinity of gullies with debris flows. We isolated and analyzed the influence of the topography on the formation of debris flows in gullies with almost identical hydrological and geological conditions and propose a new T-factor as a topographical indicator which is a combination of the catchment surface area,the percentage of the catchment area with a slope of 25—45 degree,and the average gradient of the drainage channel in the catchment. Additionally a new R-factor is proposed as a rainfall indicator which is a combination of the rainfall in 1-hour before the debris flow was triggered,the cumulative rainfall before the debris flow was triggered,and the annual rainfall. The relationship of the T factor and the R factor gives a primary threshold P for this kind of debris flow. The primary probability factor P is the combination of T and R,which gives an indication of the probability of debris flow formation.
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2016年第4期542-550,共9页
Advances in Water Science
基金
国家自然科学基金资助项目(41372366)~~
关键词
地形因子
降雨因子
泥石流
浅层滑坡
topographical factor
rainfall factor
gully type debris flow
shallow landslide
