汶川县映秀镇红椿沟特大型泥石流形成机制及堵江机理研究
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摘要
2010年8月14日,汶川县映秀镇红椿沟因连日强降雨,发生灾害性特大泥石流,完全中断都汶公路的交通,并冲入岷江形成堰塞体,致使河水改道,冲进映秀新区使数十幢房屋成为孤岛,严重危胁到灾后重建的胜利成果。研究红椿沟泥石流的基本特征、变形破坏机制、类型规模及防治对策,对防治高地震烈度泥石流灾害、确保灾后重建成果具有重要意义。以红椿沟特大型泥石流为例,在研究地质灾害形成的地质背景及条件、基本特征的基础上,分析了泥石流的形成机理及断路堵江的具体原因,预测了泥石流发展的趋势,对重要物源点进行了稳定性分析,提出了红椿沟泥石流的形成及堵江除丰富的震后松散物源、强降雨外,还与其独特的地形地貌密切相关。研究表明,红椿沟特大泥石流是从其上游甘溪铺支沟开始启动、汇集溃决,随后带动主沟物源冲入岷江,与岷江上游烧房沟泥石流冲入江中物质在江中汇集,形成堵江。红椿沟内物源丰富,必须加强防治,防止泥石流的再次危害。
On August 14,2009,a catastrophic giant debris flow occurred at Hongchun gully in Yingxiu town,Wenchuan County due to continuous heavy rainfall.It completely interrupted the traffic the Du-Wen highway and rushed to the Minjiang River and dammed the river.The river is diverted to the Yingxiu town and dozens of houses in the newly built area of Yingxiu became an island,which seriously threatened the achievements of post-disaster rehabilitation and reconstruction.The study of basic characteristics,the deformation and failure mechanisms,the types and countermeasures is of importance for control of debris flow disasters in high seismic intensity area.Taking the giant debris flow occurred at Hongchun gully as an example,the formation mechanism of the debris flow and the causes of highway and river blocking are discussed,the development trend of debris flow is predicted and the stability of key places of material sources is analyzed based on a study of geological background and conditions and basic features of geological hazards.It is pointed out that the formation and river blocking of the debris flow at Hongchun gully is not only related to loose material sources and heavy rainfall,but also closely related to the unique landform and topography.The results show that the giant debris flow at Hongchuan gully started from upstream Ganxipu branch ditch,the materials became dam and burst,then rushed into the Minjiang river together with the materials of the main ditch and converged with the materials from debris flow of upstream Shaofang gully in the Mingjiang river.So the river was dammed.The material sources in the Hongchun gully are rich.The countermeasures must be strengthened to prevent the recurrence of debris flow disasters there.
On August 14,2009,a catastrophic giant debris flow occurred at Hongchun gully in Yingxiu town,Wenchuan County due to continuous heavy rainfall.It completely interrupted the traffic the Du-Wen highway and rushed to the Minjiang River and dammed the river.The river is diverted to the Yingxiu town and dozens of houses in the newly built area of Yingxiu became an island,which seriously threatened the achievements of post-disaster rehabilitation and reconstruction.The study of basic characteristics,the deformation and failure mechanisms,the types and countermeasures is of importance for control of debris flow disasters in high seismic intensity area.Taking the giant debris flow occurred at Hongchun gully as an example,the formation mechanism of the debris flow and the causes of highway and river blocking are discussed,the development trend of debris flow is predicted and the stability of key places of material sources is analyzed based on a study of geological background and conditions and basic features of geological hazards.It is pointed out that the formation and river blocking of the debris flow at Hongchun gully is not only related to loose material sources and heavy rainfall,but also closely related to the unique landform and topography.The results show that the giant debris flow at Hongchuan gully started from upstream Ganxipu branch ditch,the materials became dam and burst,then rushed into the Minjiang river together with the materials of the main ditch and converged with the materials from debris flow of upstream Shaofang gully in the Mingjiang river.So the river was dammed.The material sources in the Hongchun gully are rich.The countermeasures must be strengthened to prevent the recurrence of debris flow disasters there.
引文
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[9]陈兴长,崔鹏、斐来政,等.溪洛渡坝区下游癞了沟泥石流发育特征及堵江可能性分析[J].灾害学,2010,25(1):45-49.
[10]宋志,巴仁基,刘守杰.磨西河特大型泥石流堵塞大渡河分析[J].灾害学,2010,25(2):73-75.
[2]四川省地质矿产勘查开发局,成都理工大学,四川省地质环境监测总站,等.国道213线都江堰至汶川公路抢通保通工程地质灾害应急调查报告[R].2008.
[3]许强,黄润秋.5.12汶川大地震诱发大型崩滑灾害动力特征初探[J].工程地质学报,2008,16(6):721-729.
[4]Takashi Koi,Norifumi Hotta,Ituro Ishigaki,et al.Prolongedimpact of earthquake-induced landslides on sediment yield in amountain watershed:The Tanzawa region,Japan[J].Geomor-phology,2008,101(3):692-702.
[5]Ashby J A.Sliding and toppling modes of failure in model andjointed rock slope[D].London:Imperial College Royal School ofMines,1971.
[6]甘建军,黄润秋,范崇荣,等.都江堰-汶川公路边坡地震破坏模式研究[J].水文地质工程地质,2011,38(3):59-65.
[7]黄润秋.汶川地震地质灾害研究[M].北京:科学出版社,2009.
[8]胡卸文,吕小平,黄润秋,等.唐家山堰塞湖大水沟泥石流发育特征及堵江危害性研究[J].岩石力学与工程学报,2009,28(4):850-858.
[9]陈兴长,崔鹏、斐来政,等.溪洛渡坝区下游癞了沟泥石流发育特征及堵江可能性分析[J].灾害学,2010,25(1):45-49.
[10]宋志,巴仁基,刘守杰.磨西河特大型泥石流堵塞大渡河分析[J].灾害学,2010,25(2):73-75.
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