摘要
为了预警泥石流的发生,需要判断泥石流的易发程度。在地质和降雨条件都大致相同的条件下,因地形条件的不同,导致一个区域的沟谷暴发泥石流的频率有着明显不同,显然地形条件是控制泥石流发育的关键因素之一。以研究岷江流域上游典型沟谷为例,通过分析地形条件对泥石流发育的影响,选用岷江流域上游典型沟谷的形成区流域面积A0、形状系数F0以及沟床纵比降J03个重要参数进行研究,比较三者相互之间的关系特征而得到一个综合的地形因子G。对比研究岷江流域典型区域以及甘肃舟曲、台湾陈有兰溪地区沟谷泥石流的暴发频率和G值,比较验证后得出:在地质和降雨条件都相近的情况下,沟谷G值越大,则越利于暴发泥石流。因此,可运用地形因子G划分某区域内沟谷泥石流的易发等级。对于岷江流域典型区域的沟谷:G≥0.21极容易暴发泥石流;0.14<G<0.21较容易暴发泥石流;G≤0.14不容易暴发泥石流。由于地质条件和降雨情况的差异,不同地区泥石流易发等级所对应的G值也将不同。
There are three groups of factors related to topography ,geology and hydrology which have influence on the formation of gully type debris flow s .In this study ,a single representative factor （G-factor） for the topography is proposed ,which can be used to give threshold values for debris flow formation .The study was carried out in the upper reaches of Minjiang River ,which is located in the Wenchuan earthquake area .During some rainfall events after the earthquake ,some gully type debris flows were triggered in some catchments .In some catchments no debris flows were triggered even though these catchments were in the vicinity of gullies with triggered debris flows .We isolated and＆amp;nbsp;analyzed the influence of the topography on the formation of debris flows because during these rainfall events the hydrological conditions were almost the same in the investigated gullies . We could also neutralize the influence of the geological factors by selecting groups of neighboring catchments located in areas with the same geological characteristics . A new G-factor is proposed in this study as a topographical indicator G ,in w hich F0 is the form factor of formation area , J0 is the average slope of formation area ,A0 is the area of formation area ,and A ＊ is the unit area （=1 km2 ） .Higher G-factor values are generally related to higher probabilities of debris flow formation .The roles of G-factor are analyzed in other areas such as Zhouqu ,Gansu ,and Chenyoulan River Watershed ,Taiwan .It shows that the higher G-factor values ,the higher probabilities of debris flow formation are in generally .In the typical areas of Minjian River areas ,it is very high probabilities of debris flow formation when G≥0 .21 . T he probabilities of debris flow formation is very low w hen G≤0 .14 .
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2014年第1期268-277,共10页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(41372366)
关键词
地形条件
泥石流
暴发频率
岷江流域
topographical factor
debris flow
gully type
Minjiang River
