汶川地震触发文家沟高速远程滑坡-碎屑流成因机理分析
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摘要
文家沟高速远程滑坡-碎屑流位于映秀—北川断裂带与灌县—安县断裂带夹持的文家沟向斜断块中,地震断裂的强烈活动引起的振动效应是形成滑坡的先决条件。滑坡源区顶端与文家沟沟口高差约1360m,突兀山体下临深切峡谷的地形使地震动荷载在山脊部位的放大效应显著,并直接导致坡体破坏;滑坡源区的地震动加速度3分量峰值分别为aEW=2.4g,aNS=2.3g,aUP=1.2g。D2gn观雾山组石灰岩斜坡具有强度渐进式分层结构,坡体表层以下约50m内的结构相对松散的残坡积层~新鲜岩体上部无法抵抗地震纵横波的周期性拉压与剪切耦合作用,被切割成为初始滑体;滑体在第八级台地边缘高位剪出后,在文家沟上游地区最高滑移速度约介于93m.s-1~122m.s-1之间。滑体上部的干碎屑流在两处路径转折端瞬间压缩沟谷内的圈闭气体,形成明显的"气垫效应",滑体下部泥石流底层液化和颗粒有效动摩擦系数随剪切速度增大而减小的效应都是导致碎屑流体高速远程滑移的关键;同时,碎屑物流通过程中还伴有明显的岸坡铲刮与翻越效应、以及树木摧削效应。汶川地震后截至2009年9月,降雨诱发碎屑堆积物形成多次泥石流,反映了地震地质灾害的链生性和长期性。
The seismic geological context,morphology,formation mechanism and evolution of Wenjiagou high-speed and long-runout debris avalanche are introduced.The debris avalanche was located at Wenjiaogou syncline block between Yingxiu-Beichuan fault and Guanxian-Anxian fault of which severe activity provided precondition for the debris avalanche.The peak of debris avalanche source area was 1360m higher than Wenjiagou valley mouth.Seismic load showed remarkable amplification effect at the ridge due to the terrain of towering hill with deep valley at the foot,and directly results in the landslide.The peak values of ground motion acceleration in 3 directions in the ridge were aEW=2.4g,aNS=2.3g,aUP=1.2g(g: the acceleration of gravity).The Guanwushan formation(D2gn)limestone slope had layered structure with progressive strength.About 50m below the slope surface was loose structural Qel+dl~upper part of fresh rock,which was cut into initial landslide mass results from the tension-compression and shear coupling effect due to seismic P-wave and S-wave.The sliding mass sheared out from edge of the 8th platform;the maximum traveling velocity of sliding mass was accelerated up to 93~122m·s-1 in Wenjiagou valley upstream.Trapped air inside of the valley was compressed by upper part of landslide mass,the dry debris flow,at 2 turnings of Wenjiagou valley;distinct"air cushion effect"was generated.Besides,the bottom layer of debris flow was liquefied;effective dynamic friction coefficient was decreased with increasing of shearing velocity;all of these effects led to the high-speed and long-runout traveling of debris flow.Simultaneously,the valley slope was scraped and crossed;the trees were cut as debris flow passed.After Wenchuan earthquake and before Sept.2009,rainfall triggered several debris flows,which indicated the continuity and long-term nature of seismic geohazard.
引文
[1]殷跃平.汶川八级地震滑坡特征分析[J].工程地质学报,2009,(1):29~38.Yin Yueping.Features of landslides triggered by the Wenchuanearthquake.Journal of Engineering Geology,2009,17(1):29~38.
    [2]Highland,L.M.,P.Bobrowsky,The Landslide Handbook—AGuide to Understanding Landslides.2008,U.S.Geological SurveyCircular 1325:Reston,Virginia.p.129.
    [3]黄润秋,裴向军,李天斌.汶川地震触发大光包巨型滑坡基本特征及形成机理分析[J].工程地质学报,2008,16(6):730~741.Huang Runqiu,Pei Xiangjun,Li Tianbin.The basic characteristicsand formation mechanism of Daguangbao large-scale landslide trig-gered by Wenchuan earthquake.Journal of Engineering Geology,2008,16(6):730~741.
    [4]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.Xu Qiang,Hu Runqiu.Kinetics characteristics of large landslidestriggered by May12th Wenchuan earthquake.Journal of Engineer-ing Geology,2008,16(6):721~729.
    [5]Heim,A.,Bergsturz und Menschenleben.Fretz und Wasmuth,Zu¨rich,1932,218.
    [6]Kent,P.E.,The transport mechanism in catastrophic rock falls.J.Geol,1966,74:79~83.
    [7]Shreve,R.L.,The Blackhawk landslide.Geol.Soc.Am.Spec.Pap.,1968,108:1~47.
    [8]Shreve,R.L.,Leakage and fluidisation in air-layer lubricated ava-lanches.Geol.Soc.Am.Bull.,1968b,79:653~658.
    [9]Voighta,B.,J.Sousa,Lessons from Ontake-san:A comparative a-nalysis of debris avalanche dynamics Engineering Geology,1994,38(3~4):261~297.
    [10]Sassa,K.Access to the dynamics of landslides during earth-quakes by a new cyclic loading high-speed ring shear apparatus.in 6th Int.Symp.Landslides.1992.Christchurch:Balkema,Rotterdam.
    [11]Davies,T.R.H.,Spreading of rock avalanche debris by mechani-cal fluidization Rock Mechanics and Rock Engineering,1982,15(1):9~24.
    [12]Campbell,C.S.,P.W.Cleary,M.Hopkins,Large-scale landslidesimulations:global deformation,velocities and basal friction.J.Geophys.Res.,1995,100:8267~8273.
    [13]胡广韬.滑坡动力学[M].北京:地质出版社,1995.Hu Guangtao.Landslide Dynamics.Beijing:Geology Press,1995.
    [14]胡厚田,刘涌江,邢爱国,等.高速远程滑坡流体动力学理论的研究[M].成都:西南交通大学出版社,2003.Hu Houtian,Liu Yongjiang,Xing Aiguo,et al.Study on fluid dy-namics theory of high-speed and long-runout landslide.Chengdu:Southwest Jiaotong University Press,2003.
    [15]程谦恭,彭建兵,胡广韬,等.高速岩质滑坡动力学[M].成都:西南交通大学出版社,1999.Cheng Qiangong,Peng Jianbing,Hu Guangtao,et al.High-speedrock landslide dynamics.Chengdu:Southwest Jiaotong UniversityPress,1999.
    [16]熊传祥,龚晓南,王成华,高速滑坡临滑变形能突变模型的研究[J].浙江大学学报(工学版),2000,34(4):443~447.Xiong Chuanxiang,Gong Xiaonan,Wang Chenghua.A deforma-tion energy catastrophic model of high-speed landslide before slid-ing.Journal of Zhejiang University(Engineering Science),2000,34(4):443~447.
    [17]肖盛燮,周小平,杨海清,等.二维高速滑坡力学模型[J].岩石力学与工程学报,2006,25(3):456~461.Xiao Shengxie,Zhou Xiaoping,Yang Haiqing,et al.Two-dimen-sional mechanical model of high-speed landslides.Chinese Jour-nal of Rock Mechanics and Engineering,2006,25(3):456~461.
    [18]刘涌江,胡厚田,白志勇.大型高速滑坡体运动的空气动力学研究[J].西南交通大学学报,2002,37(1):6~9.Liu Yongjiang,Hu Houtian,Bai Zhiyong.Aerodynamic Effect ofLarge-Scale and High-Speed Landslide.Journal of SouthwestJiaotong University,2002,37(1):6~9.
    [19]赵晓彦,胡厚田,齐明柱.云南头寨沟大型岩质高速滑坡碰撞模型试验[J].自然灾害学报,2003,12(3):99~103.Zhao Xiaoyan,Hu Houtian,Qi Mingzhu.Model experiment ofhigh-speed collision of landslide rock masses in Touzhai Gully,Yunnan.Journal of Natural Disasters,2003,12(3):99~103.
    [20]殷跃平.西藏波密易贡高速巨型滑坡特征及减灾研究[J].水文地质工程地质,2000,(4):8~11.Yin Yueping.Features and hazard mitigation of Yigong rapidhuge landslide,Bomi,Tibet.Hydrogeology and engineering geolo-gy,2000,(4):8~11.
    [21]黄润秋,中国西部地区典型岩质滑坡机理研究[J].地球科学进展,2004,19(3):443~450.Huang Runqiu.Mechanism of large scale landslides in westernChina.Advance in earth sciences,2004,19(3):443~450.
    [22]刘忠玉,马崇武,苗天德,等.高速滑坡远程预测的块体运动模型[J].岩石力学与工程学报,2000,19(6):742~746.Liu Zhongyu,Ma Chongwu,Miao Tiande,et al.Kinematic blockmodel of long run-out prediction for high-speed landslides.Chi-nese Journal of Rock Mechanics and Engineering,2000,19(6):742~746.
    [23]黄润秋,裴向军,张伟锋,等.再论大光包滑坡特征与形成机制[J].工程地质学报,2009,17(6):725~736.Huang Runqiu,Pei Xiangjun,Zhang Weifeng,et al.Further ex-amination on characteristics and formation mechanism of Da-guangbao landslide.Journal of Engineering Geology,2009,17(6):725~736.
    [24]王涛,马寅生,龙长兴,等.四川汶川地震断裂活动和次生地质灾害浅析[J].地质通报,2008,27(11):1913~1922.Wang Tao,Ma Yinsheng,Long Changxing,et al.Fault activity ofthe Wenchuan earthquake in Sichuan,China and seismic second-ary geohazards.Geological Bulletin of China,2008,27(11):1913~1922.
    [25]张倬元,王士天,王兰生.工程地质分析原理[M].北京:地质出版社,1994.Zhang Zhuoyuan,Wang Shitian,Wang Lansheng.Principles ofengineering geology analysis.Beijing:Geology Press,1994.
    [26]Li,X.,Z.Zhou,H.Yu,et al.Strong motion observations and re-cordings from the great Wenchuan Earthquake.Earthquake Engi-neering and Engineering Vibration,2008,7(3):235~246.
    [27]中华人民共和国建设部,建筑抗震设计规范(GB 50011-2001)[S].北京:中国建筑科学研究院,2001.The People s Republic of China Ministry of Construction.Codefor Seismic Design of Buildings(GB 50011-2001).Beijing:China Academy of Building Research,2001.
    [28]崔芳鹏,胡瑞林,殷跃平,等.地震纵横波时差耦合作用的斜坡崩滑效应研究[J].工程地质学报,2009,17(4):455~462.Cui Fangpeng,Hu Ruilin,Yin Yueping,et al.Numerical simula-tion of slope collapsing and sliding due to single or combined ac-tions of seismic p-and s-waves with time difference.Journal ofEngineering Geology,2009,17(4):455~462.

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