大流域泥石流成灾特征与形成机制——以金川县曾达沟“6.27”特大型泥石流为例  

Characteristics and formation mechanism of debris flow in large watershed:Take the “6.27” super large debris flow in Zengda gully,Jinchuan County as an example

作　　者：黄洪 陈宁生[1,2] 胡桂胜[1,2] 刘恩龙[4] 倪化勇[5] HUANG Hong;CHEN Ningsheng;HU Guisheng;LIU Enlong;NI Huayong(Institute of Mountain Hazards and Environment,Chinese Academy of Sciences&Ministry of Water Conservancy,Chengdu 610041,China;Key Lab of Mountain Hazards and Surface Processes,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 10049,China;State Key Laboratory of Hydraulics and Mountain River Engineering,College of Water Resources and Hydropower,Sichuan University,Chengdu 610065,China;Chengdu Center,China Geological Survey,Chengdu 610081,China)

机构地区：[1]中国科学院、水利部成都山地灾害与环境研究所,四川成都610041 [2]中国科学院山地灾害与地表过程重点实验室,四川成都610041 [3]中国科学院大学,北京100049 [4]四川大学水利水电学院,四川成都610065 [5]中国地质调查局成都地质调查中心,四川成都610081

出　　处：《自然灾害学报》2021年第5期207-216,共10页Journal of Natural Disasters

基　　金：国家重点研发计划课题-复杂山区泥石流物源量估算与判断关键技术(2018YFC1505202);国家自然基金国际(地区)合作与交流项目-多尺度滑坡泥石流灾害链发生机制与风险韧性管控(41861134008);中国科学院青年创新促进会项目(2020367)。

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1567.56 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。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.

关 键 词：曾达沟 泥石流 形成机制 前期累计降雨 工程治理 非工程治理 

分 类 号：P642.23[天文地球—工程地质学] X14[天文地球—地质矿产勘探]