【摘要】 2019年6月27日20时30分许,四川省金川县曾达乡曾达沟(流域面积125.53 km~2)暴发特大型泥石流灾害,造成房屋、基础设施、农业、公益设施损失约1.51亿元。本文通过现场勘察、室内实验、模型计算,对曾达沟泥石流的成灾机制、运动特征及过程进行分析,阐明了前期累计降雨对泥石流形成产生的影响。研究结果表明:(1)曾达沟泥石流容重为1.7 g/cm~3,平均流速为8.55 m/s,峰值流量为1 567.56 m~3/s;(2)前期累计降雨与短历时强降雨共同作用导致此次泥石流形成;(3)前期累计降雨诱发曾达沟内崩塌、滑坡和坡面坍塌发生,为泥石流的暴发创造了良好的物源条件。据估算,崩塌、滑坡物源总量约为528.2×10~4 m~3,占总物源的50%;(4)工程治理与非工程治理相结合在此次泥石流灾害中发挥良好作用,有效的避免了人员伤亡。更多还原

【Abstract】 About 20:30 on June 27, 2019, a large-scale debris flow occurred in Zengdag gully(the basin of 125.53 km~2), Zengda Township, Jinchuan County, Sichuan Province, causing a direct economic loss of about 151 million yuan in housing, infrastructure, agriculture, and public welfare facilities. The disaster mechanism, movement characteristics and process of debris flow in Zengda gully are analyzed by means of field investigation, laboratory experiment and model calculation, and the influence mechanism of early accumulated rainfall on the formation of debris flow is expounded. The results prove that:(1) The bulk density of the debris flow in Zengda gully is 1.7 g/cm~3, the average velocity is 8.55 m/s, and the peak flow discharge is 1 567.56 m~3/s;(2) The combined effect of previous accumulated rainfall and short-duration heavy rainfall led to the formation of this debris flow;(3) Collapse, landslide and slope collapse in Zenda gully were induced by accumulated rainfall in the early stage, which created good material source conditions for the outbreak of debris flow. It is estimated that the total amount of material source of collapse and landslide is about 528.2 × 10~4 m~3, accounting for 50% of the total material source;(4) The combination of engineering measures and non-engineering measures played a good role in the debris flow disaster, effectively avoiding casualties.更多还原