摘要
文章从泥石流起动条件、形成过程、固体物质起动方式、相的划分及搬运方式、阵发性和龙头等方面对黄土地区暴雨型泥石流的动力学特征进行了研究 ,并对其成因机制进行了探讨。认为 :泥石流的形成须有一定厚度的饱和土层和一定深度的地表径流 ,对于干旱、半干旱的黄土地区 ,由于土壤较干燥 ,须有大量水分下渗才能形成一定厚度的饱和土层 ,因此该区泥石流对 1h降雨量较为敏感 ;该地区泥石流固体物质起动方式较为复杂 ,部分按纯粘性土规律起动 ,部分按粘性土夹砂和无粘性砂规律起动 ;该区泥石流液相往往包括粘粒、细砂和粉砂等成分 ,所占比例较大 ,而固相所占比例较小 ;由于黄土地区多稀性泥石流 ,且沟壑密度大 ,流域支沟发育 ,经叠加作用后 ,在主沟内往往不具阵发性 ,其过程曲线近似洪水的单峰过程曲线 ;另外 ,由于该区泥石流往往不具阵发性或阵发性不明显 ,沟道内卵石之类的大颗粒数量有限 。
The paper studied dynamic feature of debris flow caused by storm in loess area and discussed its genetic mechanism from such aspects as starting conditions,development process,starting mode of solid material,phase'division and transporting mode,intermittent flow,debris flow head and so on.The following conclusions were drawn:The occurrance of debris flow required certain thickness of saturated soil layer and some depth of radial flow water.Certain thickness of saturated soil layer only formed by a quantity of water seepage(in arid and semiarid loess area) due to its drier soil.Therefore,the debris flow in this area is sensitive to one\|hour rainfall.The starting mode of solid material in debris flow is rather complicated.Part of which followed clay movement regularity and also partly followed that of sandy clay and sand.Liquid phase accounts for larger percentage of debris flow which includes clay,fine sand and silt etc,and its solid phase accounts for less percentage.Most debris flow is dilute flow which usually is not of the intermittent property in major channel after overlap action because of densely developed valley and branches of river basin in loess area.Its process graph is similar to that of single\|peak flood.In addition,there is usually no ability to form the head,because of the shortage of intermittent property and little amount of larger grains such as gravel.
出处
《中国地质灾害与防治学报》
CSCD
2002年第3期29-33,共5页
The Chinese Journal of Geological Hazard and Control
