浙江省泥石流形成及成灾特点

浙江地处我国东南沿海,近几年频繁遭受泥石流等山地灾害的危害。由于所处地理地质和气候环境,发育的泥石流有其独特的地域特征。从泥石流的发育特征、形成过程等探讨了浙江泥石流形成的机理,分析了其成灾特点。结果表明,浙江省泥石流为滑坡、崩塌转化型泥石流,泥石流的形成机理及过程主要为:强降雨下滑坡、崩塌发生,持续强降雨使得滑坡、崩塌松散物流化从而形成泥石流。滑坡、崩塌转化型泥石流在流域特征上表现为形成区坡度大,易发滑坡、崩塌,水力条件充分等。泥石流灾害具有低频性、群发性、并发性、突发性、夜发性、危害大等特点。

Cause and Damaging Characteristic of Debris Flow in Zhejiang Province

Zhejiang is a coastal province in southeastern China,and over the past few years,it is frequently suffered damages caused by mountain hazards such as debris flows and so on.Because of specific geological,geographical and climatic characteristics of the region,debris flow in Zhejiang is different from the ones in western and northern China on the features of watershed,geological environment and water source.This paper looked into the damage pattern of debris flow in Zhejiang Province,and analyzed the mechanism of debris formation according to the development characteristics and process of debris flow.The results showed that the debris flow in Zhejiang Province was transformed from landslide-collapse,which occurred when landslide and collapse took place under the triggering heavy rainfall,and the mass were fluidized into debris flow under the continuous heavy rainfall.The watersheds with highly occurrences of debris flow hazards are always the ones with steep channels,highly occurrences of landslides and collapses,and appropriate hydrological conditions.The characteristics of debris flow include: low frequency,simultaneity,recurrence,outburst,occurrence at night,and severe damages.