从黄土灾害链看溃决型泥石流形成——以叶城柯克亚乡六村为例  

From Geohazard Chain in loess to Outburst Debris Flow,taking the No.6 Village of Kekeya Town,Yecheng County as an Example

作　　者：尚彦军[1,2] 金维浚[2] 高强 李坤 帕尔哈提.祖努 魏思宇[2] Shang Yanjun;Jin Weijun;Gao Qiang;Li Kun;Parhat Zunu;Wei Siyu(Xinjiang Institute of Engineering,Urumqi,Xinjiang,830023,China;Institute of Geology and Geophysics, Chinese Academy of Sciences,Beijing,100029,China;China Institute of Geo-Environment Monitoring, China Geological Survey, Beijing,100081,China;General Institute of Water Resources and Hydropower Planning and Design,Beijing,100120,China)

机构地区：[1]新疆工程学院,新疆乌鲁木齐830023 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国地质环境监测院自然资源部地质灾害防治技术指导中心,北京100081 [4]水利部水利水电规划设计总院,北京100120

出　　处：《新疆地质》2019年第1期116-123,共8页Xinjiang Geology

基　　金：自治区重点专业建设项目;科技厅国际合作项目(20166017);国家自然基金面上项目(41772320);地质灾害防治与地质环境保护国家重点实验室项目(SKLGP2017K021)

摘　　要：集中分布于昆仑山北坡2 500～4 000 m高度上的风积土因形成时代新、搬运距离短、成壤作用弱而多为松散多孔的灰黄色粉土或黄土状土。造成重大人员伤亡的叶城"7.6泥石流事件"为近年来日益重视的黄土灾害链发生机理研究提供了一个独特案例。采用遥感影像分析、现场调查、走访、高密度电法勘探等技术方法,研究发现该事件从斜坡高位长达10～15 a发育弧形张拉裂缝开始,短时强降雨诱发破坏,产生浅层远距离滑坡,堵塞河沟成堰塞湖,土坝溃决形成稀性泥石流乃至下游洪水。本文所揭示的柯克亚乡黄土地质灾害链发生机理在南疆较常见,或可称叶城模式。研究发现,突发破坏以滑坡而非水土流失形式,缘于中高山区斜坡上的风积土厚度一般小于20 m、坡脚与侧蚀河床距离有限。本研究解释了下游河谷突然断流,次日突发洪水现象原因:中上游堰塞湖形成、滞后溃决和瞬时泥石流、洪水损害环链生性灾害。The aeolian soils in southern Xinjiang concentrated at 2 500~4 000 m height on the northern slope of Kunlun Mountains are mostly gray- yellow silt or loess- like soils due to their newly occurrence,short migration distance and weak soil formation.Yecheng 7.6 debris flow event provides a rare case for disclose the mechanism of geohazard chain in loess,which has been paid more and more attention in recent years.It was found that the event began with the development of arc tension cracks at the high slope for 10~15 years.Short-term rainstorm induced damage,resulted in shallow long-distance landslides,blocked rivers and became dammed lakes,and caused outburst debris flow and afterwards floods in the downstream.The mechanism of loess geohazard chain within Kekeya Town revealed in this paper is more common in South Xinjiang, or it can be called Yecheng Model.It is also found that the sudden slope failure is in the form of landslide rather than soil erosion, because the thickness of eolian soil on the high slopes in middle and high mountain areas is generally less than 20 m,and the distance between the foot of the slope and the scoured side-eroded river bed is limited. This paper studies and explains the causes of outburst debris flow in the gully and sudden flood in the lower reaches of the next day:formation of barrier lakes in the upper and middle reaches,delayed outburst of the landslide dam,instantaneous debris flow and afterwards floods.

关 键 词：灾害链 叶城 风积土 冻融 暴雨 

分 类 号：P642.2[天文地球—工程地质学]