大光包滑坡岩体碎裂特征及其工程地质意义
详细信息 本馆镜像全文    |  推荐本文 | | 获取馆网全文
摘要
"5·12"汶川地震发生六年以来,对地震诱发最大的大光包滑坡开展了工程地质测绘、声波检测、钻孔取芯、电镜扫描等一系列工作,研究表明该滑坡滑带产生于震旦系灯影组三段(Zd3)白云岩的层内错动带。综合研究揭示滑床岩体碎裂化宏观特征如下:滑面以下0~1 m岩体呈砂土状,砂粒含量占到60%以上;1 m以下岩体平均声波波速2 500~3 000 m/s,完整性指数趋于0.15~0.77,岩体损伤程度总体上随滑床深度增加而减小,而滑面下同一深度岩体损伤程度随滑床高程的增加而增大,局部有差异性破碎。另一方面,微观研究揭示滑带岩体压剪晶体沿解理面折扭断裂,穿晶裂纹发育,表现为部分晶体松动架立,晶间连接丧失。研究揭示的工程地质意义:(1)滑带岩体性质主要受控于层内挤压错动的泥质花斑状白云岩,该层成分复杂,风化程度高,节理发育,完整性差;(2)"5·12"地震使滑带岩体产生强烈的剪切破坏(拉张和压剪破坏)和翼裂纹扩展,岩体的抗剪强度指标及完整性系数剧降,岩体质量劣化,在启动后巨厚滑体的碾压与揉搓作用下,滑带岩体的摩阻力进一步降低。综上,大光包滑坡滑带岩体损伤碎裂化是地震荷载作用下岩体内部缺陷动态演化的累进过程,滑带所在的地层岩性及岩体结构特征为其主要内因,强震荷载是其关键的外在诱因。
Over the past six years after"5·12"Wenchuan earthquake,we have carried out engineering geological surveying,acoustic detection,coring-drilling,electron microscope scanning and other works to the Daguangbao landslide,which is the largest landslide induced by Wenchuan earthquake. Studies showed that the sliding zone of this landslide occurred in dolomite intraformational disturbed zone which was located in the third section of Denying group of Sinian system(Zd3). Comprehensive studies reveal the macroscopic characteristics of the fragmentation rock of slide bed as follows:the rock presents sandy soil within the 0–1 m depth below sliding surface,which the sand content occupy more than 60%;1m below the sliding surface,the average rock acoustic velocity is range in 2 500–3 000 m/s,in addition the integrity index of the rock tends to 0.15–0.77. On the whole,the damage degree of the rock mass generally decrease with the depth increase of slip bed,but under the same depth those increase with the elevation increasing,except the local difference broken. On the other hand,microscopic study reveals that the compression-shear crystal of rock mass of slip zone is fold and torsional fracture with lots of transgranular crack,which shows parts crystal loose and intergranular connection loss. Study reveals the significance of engineering geology as follows:(1) Property of the rock mass in sliding zone mainly controlled by argillaceous graniphyric dolomite of intraformational extrusion dislocation,which the composition of this layer is complicate with the high degree of weathering,joint development and poor integrity;(2) Under "5·12"Wenchuan earthquake,the rock mass of slide zone generated strong shear failure(tensile and compressive shear failure) and wing crack extend,which caused sharp drop of the rock shear strength index and the integrity coefficient,thus deterioration of the rock mass. Furthermore,the rolling and rubbing action of thick sliding body afther starting further promote frictional resistance reducing in the sliding zone rock mass. In summary,the fragmentation of rock mass damage of Daguangbao sliding zone is a dynamicly progressive evolution process of rock internal defects under seismic load,the lithology and rock structural characteristics of slide zone are the main intrinsic factors,earthquake loads are its key external incentives.
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制分析[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 Dagungbao occurred during the Wenchuan earthquake[J].Journal of Engineering Geology,2008,16(6):730–741.(in Chinese))
    [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 formatiom mechanism of daguangbao landslide[J].Journal of Engineering Geology,2009,17(6):725–736.(in Chinese))
    [3]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,CHENG Yuliang,WANG Jun,et al.Remote sensing research on daguangbao gigantic rock-slide triggered by Wenchuan earthquake[J].Journal of Engineering Geology,2011,19(5):674–684.(in Chinese))
    [4]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[J].岩石力学与工程学报,2012,31(10):1 969–1 982.(YIN Yueping,WANG Meng,LI Bin,et al.Dynamic response characteristics of daguangbao landslide triggered by Wenchuan earthquake[J].Chinses Journal of Rock Mechanics and Engineering Geology,2012,31(10):1 969–1 982.(in Chinese))
    [5]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[J].Journal of Engineering Geology,2013,21(2):269–281.(in Chinese))
    [6]马艳波.强震条件下巨型滑坡滑带岩体损伤特性研究—以大光包滑坡为例[硕士学位论文][D].成都:成都理工大学,2012.(MA Yanbo.Study on damage features of the rock mass in the sliding belt of the giant landslide under the strong earthquake-A case of Daguangbao landslide[M.S.Thesis][D].Chengdu:Chengdu University of Technology,2012.(in Chinese))
    [7]王小林,胡文瑄,陈琪,等.塔里木盆地柯坪地区上震旦统藻白云岩特征及其成因机理[J].地质学报,2010,84(10):1 479–1 494.(WANG Xiaolin,HU Wenxuan,CHEN Qi,et al.Characteristics and formation mechanism of upper sinian algal dolomite at the Kalpin area,Tarim Basin,Nw China[J].Acta Geologica Sinica,2010,84(10):1 479–1 494.(in Chinese))
    [8]李先炜,兰勇瑞,邹俊兴.岩石断口分析[J].中国矿业学报,1983,(1):18–24.(LI Xianwei,LAN Yongrui,ZOU Junxing.A study of rock fractures[J].Journal of China University of Mining and Technology,1983,(1):18–24.(in Chinese))
    [9]杨主恩,俞理宝,鲍秀英.扫描电镜与微观地质研究[M].北京:学苑出版社,1999:5–190.(YANG Zhuen,YU Libao,BAO Xiuying.Microgeology research in scanning electron microscopy[M].Beijing:Academy Press,1999:5–190.(in Chinese))
    [10]胡玲,刘俊来,纪沫,等.变形显微构造识别手册[M].北京:地质出版社,2009:59–96.(HU Ling,LIU Junlai,JI Mo,et al.Deformation microstructures identity manual[M].Beijing:Geological Publishing House,2009:59–96.(in Chinese))
    [11]王瑞珣.显微构造地质学[M].北京:北京大学出版社,1988:5–158.(WANG Rixun.Microscopic structural geology[M].Beijing:Peking University Press,1988:5–158.(in Chinese))
    [12]胡玲.显微构造地质学概论[M].北京:地质出版社,1998:1–221.(HU Ling.Introduction to microscopic structural geology[M].Beijing:Geological Publishing House,1998:1–221.(in Chinese))
    [13]许强,裴向军,黄润秋.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.Large-scale landslides induced by the Wenchuan Earthquake[M].Beijing:Science Press,2009:53–91.(in Chinese))
    [14]PRéAT A,KOLO K,PRIAN J,et al.A peritidal evaporite environment in the Neoproterozoic of South Gabon(Schisto-Calcaire Subgroup,Nyanga Basin)[J].Precambrian Research,2010,177(3):253–265.
    [15]福里格.碳酸盐岩微相–分析、解释及应用[M].马永生,译.北京:地质出版社,2006:1–480.(Flugel.Carbonate microfacies-analysis,interpretation and application[M].Translated hy MA Yongsheng.Beijing:Geological Publishing House,2006:1–480.(in Chinese))
    [16]张倬元,王士天,王兰生,等.工程地质分析原理[M].北京:地质出版社,2009:278–296.(ZHANG Zhuoyuan,WANG Shitian,WANG Lansheng,et al.Principles of engineering geological analysis[M].Beijing:Geological Publishing House,2009:278–296.(in Chinese))
    [17]朱志刚,魏云杰,陶连金,等.北京燕家台碎裂岩体的成因机制及其工程地质意义[J].工程地质学报,2010,18(增l):71–75.(ZHU Zhigang,WEI Yunjie,TAO Lianjin,et al.Formation mechanism of Yanjiatai cracked rock mass and engineering geological significance in Beijing[J].Journal of Engineering Geology,2010,18(Supp.l):71–75.(in Chinese))
    [18]四川省地质矿产勘查开发局化探队.中华人民共和国区域地质图说明书[R].德阳:[s.n.],1995.(Geochemical Exploration Brigade of Geology and Mineral Resources Exploration and Development Bureau of Sichuan.Geological map specification of the Peoples Republic of China[R].Deyang:[s.n.],1995.(in Chinese))

版权所有:© 2023 中国地质图书馆 中国地质调查局地学文献中心