大光包滑坡工程地质研究
|
摘要
大光包滑坡是5·12汶川M_s8.0级特大地震触发的规模最大的滑坡。滑坡位于汶川地震发震断裂上盘,距发震断裂直线距离3.0~4.5km,覆盖面积7.12km~2,体积11.59×10~8m~3,是我国有史料记载以来规模最大的滑坡,也是目前世界上已知为数不多的几个10×10~9m~3以上的超大规模滑坡之一。本文作者自2011以来,在过去工作基础上,对该滑坡开展了1:2000滑坡工程地质测绘,结合物探、坑槽探及浅孔钻探等工作,编制了滑坡工程地质系列图件,从而进一步查明了大光包滑坡的平面和空间形态、滑体结构、滑面位置和堆积特征等,获得了较为完整的滑坡要素定量数据。研究成果还原了大光包滑坡发生时的真实场景;揭示了滑坡堆积地貌特征、植被分布、岩性分布以及堆积体结构特征等,认为大光包滑坡是受强震和特定地形条件、岩体结构条件(层间剪切断层和两组陡裂结构面)控制的"楔形体"失稳。在此基础上,根据滑坡的要素组成和运动堆积特征,对滑坡进行了分区,分为滑坡断壁区、主滑堆积区和次滑堆积区3个大区,进一步划分为10个小区,分析阐明了各区特征。最后,对大光包滑坡的发生过程和形成机理进行了概要分析,将其概括为5个主要阶段:即强震拉裂阶段、锁固段剪断及"楔形体"失稳阶段、高速滑动和"急刹车"运动堆积阶段、拆离滑动阶段、断壁崩滑阶段。研究还发现:强震作用下滑带的进一步碎裂化,以及可能出现的水击作用可能是滑坡骤然启动的主要原因。
Daguangbao landslide with an area of 7.12km~2 and a volume of 1.159 billion m is the largest landslide triggered by the Wenchuan M_s8.0 Earthquake occurred on May 12~(th),2008,and also is the largest one in China and one of the few giant landslides more than one billion m~3 in the world.It is located in the hanging wall of the seismogenic fault of the Wenchuan earthquake,and 3.0-4.5km away from it.The authors' team has conducted a engineering geological survey including mapping,geophysical exploration,pitting and boreholes with a scale of1:2000 since 2011.According to the data,we finished a series of geological maps including a comprehensive plane map and 25 sections.The spatial shape of the landslide,pre- and post-failure structures,slip surface and its characteristics were further investigated and a set of quantitative data about Daguangbao landslide features was obtained.We found it was a huge " wedge" failure with a strike slipping sliding along a bedded shear fault.According to the description of witnesses and structures of the accumulation,we rebuilt the experience of the slope failure and sliding process during the strong quaking.Basically,it can be divided into five stages;shattering-tensile cracking,cutting through of the front locking section, "suddenly braking" and napping motion,detaching sliding on both sides of the accumulation and finally secondary sliding of the scarp cliff.The accumulation can be divided into three area and ten sub-areas.They are the main scarp area,the accumulation area,and tine back depression area,which corresponding to three,four and three sub-areas respectively.
Daguangbao landslide with an area of 7.12km~2 and a volume of 1.159 billion m is the largest landslide triggered by the Wenchuan M_s8.0 Earthquake occurred on May 12~(th),2008,and also is the largest one in China and one of the few giant landslides more than one billion m~3 in the world.It is located in the hanging wall of the seismogenic fault of the Wenchuan earthquake,and 3.0-4.5km away from it.The authors' team has conducted a engineering geological survey including mapping,geophysical exploration,pitting and boreholes with a scale of1:2000 since 2011.According to the data,we finished a series of geological maps including a comprehensive plane map and 25 sections.The spatial shape of the landslide,pre- and post-failure structures,slip surface and its characteristics were further investigated and a set of quantitative data about Daguangbao landslide features was obtained.We found it was a huge " wedge" failure with a strike slipping sliding along a bedded shear fault.According to the description of witnesses and structures of the accumulation,we rebuilt the experience of the slope failure and sliding process during the strong quaking.Basically,it can be divided into five stages;shattering-tensile cracking,cutting through of the front locking section, "suddenly braking" and napping motion,detaching sliding on both sides of the accumulation and finally secondary sliding of the scarp cliff.The accumulation can be divided into three area and ten sub-areas.They are the main scarp area,the accumulation area,and tine back depression area,which corresponding to three,four and three sub-areas respectively.
引文
[1]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.Basic characteristics and formation mechanism of the largest scale landslide at Daguangbao occurred during the Wenchuan earthquake[J].Journal of Engineering Geology,2008,16(6):730~741.
[2]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 examination on characteristics and formation mechanism of Daguangbao landslide[J].Journal of Engineering Geology,2009,17(6):725~736.
[3]Huang R Q,Li W.Analysis of the geo-hazards triggered by the 12May 2008 Wenchuan Earthquake,China[J].Bulletin of Engineering Geology and the Enviroment,2009,68(3):363~371.
[4]许强,裴向军,黄润秋,等.汶川地震大型滑坡研究[M].北京:科学出版社,2009,53~91.Xu Qiang,Pei Xiangjun,Huang Runqiu,et al.Large-scale landslides induced by the Wenchuan earthquake[M].Beijing:Science Press,2009,53~91.
[5]Huang R Q,Pei X J,Fan X M,et al.The characteristics and failure mechanism of the largest landslide triggered by the Wenchuan earthquake,May 12,2008,China[J].Landslides,2012,9(1):131~142.
[6]殷跃平,成余粮,王军,等.汶川地震触发大光包巨型滑坡遥感研究[J].工程地质学报,2011,19(5):674~684.Yin Yueping,Yu Chengliang,Wang Jun,et al.Remote sensing research on Daguangbao gigantic rockslide triggered by Wenchuan earthquake[J].Journal of Engineering Geology,2011,19(5):674~684.
[7]殷跃平,王猛,李滨,等.汶川地震大光包滑坡动力响应特征研究遥感研究[J].岩石力学与工程学报,2012,31(10):1969~1982.Yin Yueping,Wang Meng,Li Bin,et al.Dynamic response characteristics of Daguangbao landslide triggered by Wenchuan earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(10):1969~1982.
[8]许向宁,李胜伟,王小群,等.安县大光包滑坡形成机制与运动学特征讨论[J].工程地质学报,2013,21(2):269~281.Xu Xiangning,Li Shengwei,Wang Xiaoqun,et al.Characteristics of formation mechanism and kinematics of Daguangbao landslide caused by Wenchuan earthquake Sichuan China[J].Journal of Engineering Geology,2013,21(2):269~281.
[9]Satoshi T,Kyoji S,Osamu N.Simulation of the largest landslide caused by the 2008 Wenchuan earthquake by rapid-landslidemovement simulation[J].Earthquake-Induced Landslides,2013,575~582.
[10]Zhang Y B,Chen G Q,Zheng L,et al.Numerical analysis of the largest landslide induced by the Wenchuan earthquake,May 12,2008 using DDA[J].Earthquake-Induced Landslides,2013,617~626.
[11]中华人民共和国地质图说明书(比例尺:1∶50000)清平幅[S].四川省地质矿产局化探队,1995.Geological map specificaton of the People's Republic of China(Scale:1:50000)Qingping serial[S].Geochemical Exploration Brigade of Geology&Mineral Resources Exploration&Development Bureauof Sichuan,1995.
[12]张倬元,董孝壁,刘汉超.世界滑坡目录工作组建议的滑坡术语[J].地质灾害与环境保护,1995,6(1):1~6.Zhang Zhuoyuan,Dong Xiaobi,Liu Hanchao.The multilingual landslides glossary suggested by WP/WLI[J].Journal of Geological Hazards and Environment Preservation,1995,6(1):1~6.
[13]孙广忠.岩体结构力学[M].北京:科学出版社,1988.Sun Guangzhong.Rockmass structural mechanics[M].Beijing:Science Press,1988.
[14]黄润秋.岩石高边坡稳定性工程地质分析[M].北京:科学出版社,2012.Huang Runqiu.Engineering geology for high rock slopes[M].Beijing:Science Press,2012.
[15]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 of engineering geological analysis[M].Beijing:Geological Publishing House,1994.
[16]黄润秋,余嘉顺.软弱夹层特性对地震波强度影响的模拟研究[J].工程地质学报,2003,11(3):312~317.Huang Runqiu,Yu Jiashun.Modelling of the effects of properties of a buried weak layer on seismic waves[J].Journal of Engineering Geology,2003,11(3):312~317.
[2]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 examination on characteristics and formation mechanism of Daguangbao landslide[J].Journal of Engineering Geology,2009,17(6):725~736.
[3]Huang R Q,Li W.Analysis of the geo-hazards triggered by the 12May 2008 Wenchuan Earthquake,China[J].Bulletin of Engineering Geology and the Enviroment,2009,68(3):363~371.
[4]许强,裴向军,黄润秋,等.汶川地震大型滑坡研究[M].北京:科学出版社,2009,53~91.Xu Qiang,Pei Xiangjun,Huang Runqiu,et al.Large-scale landslides induced by the Wenchuan earthquake[M].Beijing:Science Press,2009,53~91.
[5]Huang R Q,Pei X J,Fan X M,et al.The characteristics and failure mechanism of the largest landslide triggered by the Wenchuan earthquake,May 12,2008,China[J].Landslides,2012,9(1):131~142.
[6]殷跃平,成余粮,王军,等.汶川地震触发大光包巨型滑坡遥感研究[J].工程地质学报,2011,19(5):674~684.Yin Yueping,Yu Chengliang,Wang Jun,et al.Remote sensing research on Daguangbao gigantic rockslide triggered by Wenchuan earthquake[J].Journal of Engineering Geology,2011,19(5):674~684.
[7]殷跃平,王猛,李滨,等.汶川地震大光包滑坡动力响应特征研究遥感研究[J].岩石力学与工程学报,2012,31(10):1969~1982.Yin Yueping,Wang Meng,Li Bin,et al.Dynamic response characteristics of Daguangbao landslide triggered by Wenchuan earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(10):1969~1982.
[8]许向宁,李胜伟,王小群,等.安县大光包滑坡形成机制与运动学特征讨论[J].工程地质学报,2013,21(2):269~281.Xu Xiangning,Li Shengwei,Wang Xiaoqun,et al.Characteristics of formation mechanism and kinematics of Daguangbao landslide caused by Wenchuan earthquake Sichuan China[J].Journal of Engineering Geology,2013,21(2):269~281.
[9]Satoshi T,Kyoji S,Osamu N.Simulation of the largest landslide caused by the 2008 Wenchuan earthquake by rapid-landslidemovement simulation[J].Earthquake-Induced Landslides,2013,575~582.
[10]Zhang Y B,Chen G Q,Zheng L,et al.Numerical analysis of the largest landslide induced by the Wenchuan earthquake,May 12,2008 using DDA[J].Earthquake-Induced Landslides,2013,617~626.
[11]中华人民共和国地质图说明书(比例尺:1∶50000)清平幅[S].四川省地质矿产局化探队,1995.Geological map specificaton of the People's Republic of China(Scale:1:50000)Qingping serial[S].Geochemical Exploration Brigade of Geology&Mineral Resources Exploration&Development Bureauof Sichuan,1995.
[12]张倬元,董孝壁,刘汉超.世界滑坡目录工作组建议的滑坡术语[J].地质灾害与环境保护,1995,6(1):1~6.Zhang Zhuoyuan,Dong Xiaobi,Liu Hanchao.The multilingual landslides glossary suggested by WP/WLI[J].Journal of Geological Hazards and Environment Preservation,1995,6(1):1~6.
[13]孙广忠.岩体结构力学[M].北京:科学出版社,1988.Sun Guangzhong.Rockmass structural mechanics[M].Beijing:Science Press,1988.
[14]黄润秋.岩石高边坡稳定性工程地质分析[M].北京:科学出版社,2012.Huang Runqiu.Engineering geology for high rock slopes[M].Beijing:Science Press,2012.
[15]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 of engineering geological analysis[M].Beijing:Geological Publishing House,1994.
[16]黄润秋,余嘉顺.软弱夹层特性对地震波强度影响的模拟研究[J].工程地质学报,2003,11(3):312~317.Huang Runqiu,Yu Jiashun.Modelling of the effects of properties of a buried weak layer on seismic waves[J].Journal of Engineering Geology,2003,11(3):312~317.