节点文献
5.12汶川地震对岷江上游河道的影响——以都江堰—汶川河段为例
River Channel Change of the Upper of Minjiang River by 5.12 Wenchuan Earthquake:A Case Study of the Section of Dujiangyan-Wenchuan
【摘要】 5.12汶川地震造成灾区地质灾害广泛发育,土壤侵蚀剧烈,极大地破坏了灾区环境,改变了灾区自然环境演化的进程。通过实地调查与观测,并结合遥感资料数据,分析了岷江上游都江堰—汶川河段地质灾害的发育特征,揭示了崩塌、滑坡、泥石流、堰塞湖及工程建设对岷江上游河道的影响形式,分析了上游河道的变化趋势。研究表明,震后崩塌、滑坡单侧挤占河道使岷江干流河宽普遍压缩5~10 m,顶冲挤占使河道一般变窄20~30 m,最窄处仅为原河道的1/3(30~40 m)。泥石流堆积物进入河道而淤积河道,甚至阻断岷江而形成堰塞湖,造成河床上升,河曲加剧,工程建设及灾害点处置使河宽变窄。在多重因素的共同作用下,今后10~20 a,尤其震后5 a内,汶川-映秀河段,河道变窄,河曲加剧,河床升高,河床比降呈增大趋势,映秀—紫坪铺河段淤积明显,河床升高。从长期变化来看,地震次生山地灾害加速了岷江上游高山峡谷区河道的自然演化进程,河床升高并展宽,河床比降降低,河谷逐渐向宽谷形态演化,河床趋于稳定。
【Abstract】 This paper discusses the river channel change of the upper of Minjiang River by geo-hazards induced by 5.12 Wenchuan Earthquake,including collapse,landslide,debris flow,geo-hazard dam lake and so on.It also studies the characteristics of geo-hazards distributed in Dujiangyan-Wenchuan Highway and establishes the mechanisms of river channel change by geo-hazards on the basis of the field observations and the remote sensing image analysis.After this earthquake,most Minjiang River channel width decreased by 5-10 m due to the deposition of collapses and landslides,somewhere by 20-30 m,and the narrowest remaining only 30-40 m.Debris flow delivered quantity of solid materials into the River and deposited on the river channel,blocked the river and generated geo-hazards dam lake,resulting in the rise of the riverbed and the increase of the river curve.Generally,in the coming 10-20 years,especially the next 5 years,the river channel of Wenchuan-Yingxiu would become narrower with more curves and higher riverbed slope.While the riverbed of Yingxiu-Zipingpu would rise rapidly because of the deposition of sediments from the upper Minjiang River.In the long term,the geo-hazards by this earthquake will accelerate the natural evolvement of the upper reaches of the Minjiang River and induce riverbed rise and extension,riverbed slope reduction and gorge expansion.
【Key words】 Wenchuan Earthquake; created geo-hazard; Minjiang River upper; river channel change;
- 【文献出处】 地质科技情报 ,Geological Science and Technology Information , 编辑部邮箱 ,2009年02期
- 【分类号】P694
- 【被引频次】10
- 【下载频次】384