云南东川蒋家沟泥石流形成内因初探

Study of internal factors for debris flow occurrence in Jianjia Ravine,Dongchun of Yunnan

泥石流形成的因素众多,不仅与地形地貌、降雨特征、地震、人类活动等外部因素有关,还与泥石流岩土体自身的黏土矿物成分、颗粒级配、化学成分、土体分散性、地下水环境等内部因素密切相关。在室内对蒋家沟泥石流源区土体进行黏土矿物分析、颗粒分析、化学成分定量分析、分散度和ESP值测试、地下水分析,初步探讨了蒋家沟泥石流形成的内在原因,得到:蒋家沟泥石流体的黏土矿物成分以伊利石为主,占30%,其化学成分也与伊利石接近;ESP值、分散度平均值分别达到24.6%、59.1%,属于高分散性土,且土壤贫瘠;地下水矿化度高,硬度大,破坏了岩土体自身的结构和稳定性,形成大量松散物质,为泥石流的形成提供丰富的物源。

Debris flow is characteristics of rainfall, caused by many factors; it is earthquake and human activity, distribution, chemical composition, soil dispersion degree minerals analysis, grain size distribution analysis, chemical not only related to external factors such as topographical features, but also to internal factors; for example, clay minerals, grain size and groundwater. Indoor experiments are carried out including clay composition quantitative analysis, dispersion degree and exchangeable sodium percentage （ESP） test, ground water analysis. As a result, it is found that the Illite is the main clay mineral in the soil mass of Jiangjia Ravine （occupied 30 percent of the soil mass）; the chemical composition of soil mass in Jiangjia Ravine is similar to Illite, it＇s average value of ESP and dispersion degree are 24.6 % and 59.1%, respectively; it is high dispersive soil and barren; the structure and stability of rock and soil mass in Jiangjia Ravine is destroyed by the high salinity and high hardness groundwater; a large number of loose material is produced and a wealth of source material for debris flow is orovided.