摘要
通过对云南蒋家沟流域上游泥石流形成源区的长时间雨季观测,分析了短历时暴雨条件下沟岸坡体的重力侵蚀过程以及上游支沟泥石流的形成过程。结果表明:尽管蒋家沟源区沟岸坡体坡度较大,但由于土体密实,且大部分处于非饱和状态,受基质吸力的影响,土体强度较高,坡体整体是稳定的。降雨过程中,由于短历时暴雨的降水入渗只能影响坡体表层的含水量,对坡体的整体稳定性影响较小;上游支沟中的洪水和泥石流冲刷坡脚、掏蚀沟床产生了大量的滑塌,是上游沟岸坡体重力侵蚀的主要方式,重力侵蚀使得原来密实的沟岸坡体变得松散,强度大大降低,为泥石流的暴发提供了固体物质基础。在暴雨过程中,这些松散堆积物饱和并在其自身重力和沟道径流的作用下启动,形成上游的支沟泥石流。
The gravitational erosion and the debris flow initiation process under the condition of short duration rainstorm are analyzed by continuous observing the rainy season in the headstream area of Jiangjia ravine. The results show that although the bank slope is steep, the strength of the soil is high for the reason of matrix suction, the bank slope is rather stable. Short duration rainstorm can only influence the water content of soil of shallow layer of the slope, and has little influence on the global stability of the slope. At the same time, the floods and debris flows in the gully down cut the gully bed, and scour the foot of the bank slope, It is the main type of gravitational erosion, The gravitational erosion makes the dense dry gravel soil of bank slope become loose and its shear strength become decline, which provides large amounts of solid materials for the eruption of debris flows. Under the condition of high intensity rainfall, those loose solid materials in the branch gully are saturated and initiate to form the debris flows in the headstream area of Jiangjia ravine.
出处
《安徽农业科学》
CAS
北大核心
2008年第8期3319-3322,共4页
Journal of Anhui Agricultural Sciences
关键词
重力侵蚀
支沟泥石流
土体含水量
滑塌
启动
Gravitational erosion
Debris flow
Water content
Collapse
Initiation
