震区泥石流物源与冲出量的关系--以四川汶川县簇头沟为例  

Relationship Between Debris Flow Sediments and Amount of Debris Flow Discharges in Earthquake Affected Region:A Case Study of the Cutougou Valley in Wenchuan County,Sichuan Province,China

作　　者：胡旭东 沈已桐[3] 胡凯衡 张晓鹏[2] 许文年 HU Xudong;SHEN Yitong;HU Kaiheng;ZHANG Xiaopeng;XU Wennian(Key Laboratory of Geological Hazardson ThreeGorges Reservoir Area(China Three Gorges University),MinistryofEducation,China Three GorgesUn iversity,Yichang443002,Hubei,China;College of Civil Engineering and Architecture,China Three Gorges University,Yichang443002,Hubei,China;College of Hydraulic and Environment Engineering,China Three Gorges University,Yichang443002,Hubei,China;Institute of Mountain Hazards and Environment,Chinese Academy of Sciences and Ministry of Conservancy,Chengdu610041,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002 [3]三峡大学水利与环境学院,湖北宜昌443002 [4]中国科学院、水利部成都山地灾害与环境研究所,成都610041

出　　处：《山地学报》2022年第3期369-383,共15页Mountain Research

基　　金：国家自然科学基金(42001002);中国科学院山地灾害与地表过程重点实验室开放基金(KLMHESP-20-02);长江科学院开放研究基金(CKWV2021888/KY);湖北省教育厅科学技术研究计划重点项目(D20201205)。

摘　　要：汶川地震诱发的崩滑体不断地动态演变,为泥石流提供了丰富的松散固体物源,造成震后数年间暴发多次群发性泥石流灾害。分析震区崩滑体(物源)时空上的变化以及与泥石流规模(冲出量)大小的关系,可为震后灾害链的长期效应和防灾减灾提供科学依据。目前,冲出量多基于单次泥石流或多次泥石流后形成的堆积物进行估算,利用遥感技术结合现场踏勘来确定泥石流冲出物的相关研究不多。本文选取汶川震区簇头沟流域为研究对象,通过野外调查、遥感解译和冲出量计算模型构建相结合的方法,分析流域内物源动态演变特征,探究沟道内崩滑体物源量变化与簇头沟多次泥石流冲出量的关系。结果表明:(1)簇头沟下游支沟物源量在2013年泥石流后不断减少,而上游支沟内物源量自2019年泥石流后增加显著;(2)三次泥石流的物源量与冲出量呈现一定的线性关系,而总冲出量相对于流域内总物源量的占比不足5%,仍有大量物源堆积于沟道内;(3)主沟道拦沙坝的拦蓄能力逐年下降,需继续加强清淤力度,且上部沟道和支沟亦应增加相应的防治措施。本研究有助于认识震区崩滑体演变特征及其对震后泥石流的影响,并为优化泥石流灾害防治工程选址提供理论指导。Massive landslide mass(sediments)generated by the Wenchuan Earthquake are constantly evolving dynamically,typically for years providing a rich source of loose geo-materials for debris flow motivation,resulting in group-occurring of post-shock debris flows.It is quite necessary in science to analyze the temporal and spatial patterns of these landslide mass(sediment)in the post-shock areas and determine their geophysical association with debris flow scale(the amount of debris flow discharges),undoubtedly by which it can provide scientific basis for evaluation of long-term effects of post-quake geohazard chain,as well as for policymaking of post-shock geohazard control.Research on calculation of the amount of debris flow discharges was mostly estimated based on the accumulation formed by a single debris flow or multiple debris flows;there was still a lack of research using remote sensing technology and field survey to determine it.In this study,the Cutougou valley lied in the quake-hit area was selected as research target.Research approaches,including field investigation,remote sensing interpretation and improved numerical calculation were combined to investigate the dynamic variation of the landslide mass conformation in the valley,and the association between the change of sediment storages in the gully with multiple debris flow discharges.Following facts are obtained:(1)The storage of landslide mass in lower branch of the Cutougou valley had decreased after debris flow events in 2013 while in the upper branch there were noticeable increments in sediments after debris flow events in 2019.(2)There was a certain linear relationship between the storage of landslide mass and debris flow discharges;and the total amount of debris flow discharges accounted for less than 5%of the total storage of landslide mass,still abundant sediments to be remained in the gully.(3)The retaining capacity of check dam decreased year by year,so it is necessary to dredge the dam continually;and consequent prevention and control measures are

关 键 词：泥石流 物源 动态变化 泥石流冲出量 地震 遥感解译 汶川 簇头沟 

分 类 号：P954[天文地球—自然地理学]