冻融条件下冰碛补给型泥石流物源汇集过程与灾变初探

Source Converge Process and Hazards of Moraine-supply Debris Flow under the Condition of Freezing and Thawing

冻融作用在高寒山区以冰碛作为物源补给的泥石流形成及演化过程中起着重要的作用。针对冻融条件下冰碛补给型泥石流物源的汇集特征,结合泥石流物源区沟道岸坡的微地貌特征,通过分析冻融条件下松散物源汇集的影响因素、汇集阶段及汇集过程与暴发频率的关系,认为冻融条件下冰碛补给型泥石流的物源汇集过程可分为三种汇集方式(循环式冻融汇集、季节性冻融汇集及坡向式冻融汇集)和三个连续阶段(物源空旷阶段、物源丰富阶段及物源充足阶段)。在冰碛补给型泥石流物源汇集阶段划分的基础上,对在不同阶段泥石流发生灾变的可能性进行了分析和预测,并根据不同灾变阶段提出了相应的防灾减灾对策。

Freezing and thawing plays quite an important role in the formation and evolution of moraine-supply debris flow in alpine areas.According to source converge characteristics of moraine-supply debris flow under the condition of freezing and thawing,combining with the micro-topography of specific sites in the source areas,by analyzing influencing factors and converge stages of loose source converge under the condition of freezing and thawing,and the relationship between converge process and frequency,the source converge process is discussed to be of 3 types（circular converge,seasonal converge and slope-direction converge） and 3 stages（clear source stage,abundant source stage and sufficient source stage）.Based on the stage division,the probability of debris flow outburst in different source converge stages are analyzed and predicted,and corresponding mitigating plans are put forward according to the different stages.