泥石流的形成条件及灾害评估方法——以大寨沟流域泥石流灾害评估为例

首先从形成条件来看,大寨沟堆积物储量丰富、谷深坡陡、流水丰富,为泥石流的形成提供了良好的条件.然后从以下3个方面对泥石流灾害进行评估:(1)按照谭炳炎建立的数量化综合评判方法对该泥石流沟严重(易发)程度进行了数量化综合评判,结果评分为77,为轻微等级,易发程度低;(2)对不同频率下泥石流爆发时泥石流的流量、流速和规模等泥石流的关键特征值进行了计算和确定;(3)根据最新的泥石流危险度评价成果对危险度进行了计算,为0.56,属于中度危险,利用刘希林提出的多次泥石流冲出堆积模型计算,位于沟口的水电站枢纽区处在危险范围之中.

The Formation Condition and Disaster Assessment of Debris Flow——Take Dazhaigou Valley as an Example

The ditch of dazhaigou valley locate within spillway tube and infall in the neighborhood of baihetan hydropower station which has been planned to constructed on the lower reaches of the jinsha river.Debris flow,however,is active in this valley,a great threat to the construction of hydropower station there.Own and evaluate debris flow disaster in dazhaigou valley,which is very importment to countermeasures research for baihetan hydropower station.As far as the formation condition,it have hundards of accumulaion materials and a great deal of rain,the sloping fields of the ditch valley is steep,provided the good condition for the formation of the debris flow.Then evaluate the debris flow from four aspects of the following:(1) According to numerical marks of debris flow gully's seriousness which was established by Tan Bin-yan,the result of assessment is 77 which Belongs to a slight grade;(2) Calculate the characteristic number as Discharge,current velocity and scale to debris flow in different frequency;(3)According to the latest developments for the assessment method,hazard degree is 0.56 which belongs to a middle grade,according to model of debris flow's accumulation which was established by Liu Xi-lin,the flat estimate map of the biggest dangerous range is acquired.