黄土高原泥流灾害成因及特征  

Formation Causes and Features of Mudflows in the Loess Plateau, China

作　　者：马东涛[1] 崔鹏[1] 张金山[1] 李鸿琏[2] 

机构地区：[1]中国科学院水利部成都山地灾害与环境研究所,四川成都610041 [2]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《干旱区地理》2005年第4期435-440,共6页Arid Land Geography

基　　金：国家自然科学基金项目西部重大研究计划(No.90202007)成都山地所人才引进项目(Y1006)资助

摘　　要：黄土泥流是黄土地区一类重要的灾害地貌过程,是泥石流的一个特殊类型,是水土流失的一种特殊形式,也是山地环境恶化、水土流失极严重的标志。本文在对黄土泥流这一黄土高原特有的严重水土流失现象的分布、成因、物质组成、动静力学性质、堆积形态等全面系统研究的基础上,对其和一般泥石流与高含沙水流做了初步对比和分析,揭示了黄土泥流灾害的形成规律、运动机制和沉积特征。Triggered by outburst flood, mudflow is an indicator of the most serious soil erosion process a kind of debris flow and also a form of soil erosion, and it is in the Loess Plateau. More than 98% of the solid contents in the fluid are composed of sand, silt and clay grains, the average grain size of which is 0.025 mm. Mudflow occurs mainly in the northwest Shanxi, north Shaanxi, east and west Gansu, the 4 main regions in the Loess Plateau, and mudflow also occurs dispersedly in the marginal zones of the Qinghai-Tibet Plateau and the Mongolia Plateau. The occurrence of mudflow is based on the plentiful Quaternary loess deposits, heavy rainfall and extensively distributed gullies and ravines. Moreover, reclamation on steep slopes, deforestation, excessive pasturing and others irrational human activities also trigger a great number of artificial mudflows in the Loess Plateau. According to the physical and mechanical properties, mudflows can be classified into semi-viscous, viscous and plastic categories. The higher the fine-grain soil content in the mudflow fluid is, the greater the viscosity and static stress of mudflow fluid will be. Composition of solid materials in mudflow fluid is homogeneous because of the homogeneous loess deposits. Velocity of mudflows varies in a range from 1.32 m/s to 5.59 m/s, but it is only 0.073 m/s in some mudflows with high density and viscous-plastic fluid. The discharge of mudflows is several to several ten times higher than that of outburst floods in the same ravine. Mudflow deposits are generally composed of loess with little sand, pebbles and Ca nodules, so the granularity distribution is similar to that of loess. In the course of motion, mudflows erode and polish ravine beds and bank slopes, and some polishing faces form on their surfaces. A great number of mud-pebble balls and loess pieces are deposited at ravine beds and mudflow alluvial fans. Mudflows can result in the dangers and disasters to agriculture, cities, towns, mining areas, main traffic lines in the plateau and the

关 键 词：黄土高原 泥流 形成条件 特征 

分 类 号：P642.23[天文地球—工程地质学]