大光包滑坡层间错动带液化特性及滑坡启动成因探讨
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摘要
大光包滑坡是2008年汶川地震触发的最大规模滑坡,其剪滑破坏发生在斜坡先期构造层间错动带内,该带主要由糜棱化、角砾化的构造碎裂物质组成,且具有显著地下水赋存与运移特征。为探讨强震过程地下水参与下该错动带动力学行为及对大光包滑坡启动的可能影响,取错动带材料,室内开展系列饱水静三轴、单向和双向动三轴试验,分析该材料液化特性。试验结果表明:材料具有较强的潜在液化能力;单向和双向动载作用下材料均能液化,但双向振动液化速率更快,且动强度比单向降低约20%;双向振动下材料液化速率随循环偏应力和径向循环应力增大而加快,相位差180o比0o液化速率更快。研究表明,对于产状倾斜(N2°W/NE/30°)的大光包滑坡层间错动带,双向动三轴试验动力条件可能更接近实际应力状态;强震过程,该错动带液化可能是大光包滑坡突然启动原因。
The Daguangbao(DGB) landslide was the largest landslide triggered by the 2008 Wenchuan earthquake. Its shear-slip failure occurred in the pre-structural interlayer dislocation zone of the slope, which is mainly composed of mylonitized and brecciated tectonic fragments, and has obvious characteristics of groundwater occurrence and movement. In order to study the dynamic behavior of the dislocation zone and its possible influence on the start-up of Daguangbao landslide under the participation of groundwater during strong earthquakes, a series of triaxial tests including hydrostatic triaxial, unidirectional and bi-directional dynamic triaxial tests was conducted in the laboratory on the materials sampled from dislocation zone to analyze the liquefaction characteristics of the materials. The experimental results show that the material has strong potential liquefaction capacity; under unidirectional and bi-directional dynamic loads, the material can liquefy, but the liquefaction rate of bi-directional vibration is faster, and the dynamic strength decreases by about 20% than that of unidirectional vibration. Under bi-directional vibration, the liquefaction rate of material increases with the increase of cyclic deviating stress and radial cyclic stress, and the liquefaction rate under the phase difference 180ois faster than that under the phase difference 0o. The dynamic condition of bi-directional triaxial test may be closer to the actual stress state for the interlaminar staggered zone of Daguangbao landslide with inclined occurrence(N2 o W/NE/30 o); liquefaction of the staggered zone may be the cause of the sudden start of Daguangbao landslide during the strong earthquake.
The Daguangbao(DGB) landslide was the largest landslide triggered by the 2008 Wenchuan earthquake. Its shear-slip failure occurred in the pre-structural interlayer dislocation zone of the slope, which is mainly composed of mylonitized and brecciated tectonic fragments, and has obvious characteristics of groundwater occurrence and movement. In order to study the dynamic behavior of the dislocation zone and its possible influence on the start-up of Daguangbao landslide under the participation of groundwater during strong earthquakes, a series of triaxial tests including hydrostatic triaxial, unidirectional and bi-directional dynamic triaxial tests was conducted in the laboratory on the materials sampled from dislocation zone to analyze the liquefaction characteristics of the materials. The experimental results show that the material has strong potential liquefaction capacity; under unidirectional and bi-directional dynamic loads, the material can liquefy, but the liquefaction rate of bi-directional vibration is faster, and the dynamic strength decreases by about 20% than that of unidirectional vibration. Under bi-directional vibration, the liquefaction rate of material increases with the increase of cyclic deviating stress and radial cyclic stress, and the liquefaction rate under the phase difference 180ois faster than that under the phase difference 0o. The dynamic condition of bi-directional triaxial test may be closer to the actual stress state for the interlaminar staggered zone of Daguangbao landslide with inclined occurrence(N2 o W/NE/30 o); liquefaction of the staggered zone may be the cause of the sudden start of Daguangbao landslide during the strong earthquake.
引文
[1]殷跃平.汶川八级地震地质灾害研究[J].工程地质学报,2008,16(4):433-444.YIN Yue-ping.Researches on the geo-hazards triggered by Wenchuan earthquake,Sichuan[J].Journal of Engineering Geology.2008,16(4):433-444.
[2]BURCHFIEL B C,ROYDEN L H,VAN DER HILST RD,et al.A geological and geophysical context for the Wenchuan earthquake of 12 May 2008,Sichuan,People’s Republic of China[J].GSA Today.2008,18(7):4-11.
[3]LI Y Q,JIA D,SHAW J H,et al.Structural interpretation of the coseismic faults of the Wenchuan earthquake:three-dimensional modeling of the Longmen Shan fold-and-thrust belt[J].Journal of Geophysical Research,2010,115(B04317):1-26.
[4]GORUM T,FAN X M,VAN WESTEN C J,et al.Distribution pattern of earthquake-induced landslides triggered by the 12 May 2008 Wenchuan earthquake[J].Geomorphology,2011,133(3):152-167.
[5]DAI F C,XU C,YAO X,et al.Spatial distribution of landslides triggered by the 2008 Ms 8.0 Wenchuan earthquake,China[J].Journal of Asian Earth Sciences,2011,40(4):883-895
[6]许强,李为乐.汶川地震诱发大型滑坡分布规律研究[J].工程地质学报,2010,18(6):818-826.XU Qiang,LI Wei-le.Distribution of large-scale landslides induced by the Wenchuan earthquake[J].Journal of Engineering Geology,2010,18(6):818-826.
[7]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 Run-qiu,PEI Xiang-jun,LI Tian-bin.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.
[8]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):1969-1982.YIN Yue-ping,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.
[9]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,2013,2:269-281.XU Xiang-ning,LI Sheng-wei,WANG Xiao-qun,et al.Characteristics of formation mechanism and kinematics of Daguangbaolandslide caused by Wenchuan earthquake,Sichuan,China[J].Journal of Engineering Geology,2013,2:269-281.
[10]ZHANG H,LIU S G,WANG W,et al.A new DDAmodel for kinematic analyses of rockslides on complex3-D terrain[J].Bulletin of Engineering Geology&the Environment,2016:1-17.
[11]SONG Y,HUANG D,CEN D.Numerical modeling of the 2008 Wenchuan earthquake-triggered Daguangbao landslide using a velocity and displacement dependent friction law[J].Engineering Geology,2016,215:50-68.
[12]WU J H,DO T N,CHEN C H,et al.New geometric restriction for the displacement-constraint points in discontinuous deformation analysis[J].International Journal of Geomechanics.2016,17(5):E4016002.
[13]裴向军,黄润秋,崔圣华,等.大光包滑坡岩体碎裂特征及其工程地质意义[J].岩石力学与工程学报,2015,34(增刊1):3106-3115.PEI Xiang-jun,HUANG Run-qiu,CUI Sheng-hua,et al.The rock mass cataclastic characteristics of Daguangbao landslide and its engineering geological significance[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Suppl.1):3106-3115.
[14]YANG C M,CHENG H Y,TSAO C C,et al.The kinematics and initiation mechanisms of the earthquake-triggered Daguangbao landslide[C]//EGUGeneral Assembly Conference.EGU General Aseembly Conference Abstracts.[S.l.]:[s.n.].2015.
[15]黄润秋,裴向军,崔圣华.大光包滑坡滑带岩体碎裂特征及其形成机制研究[J].岩石力学与工程学报,2016,35(1):1-15.HUANG Run-qiu,PEI Xiang-jun,CUI Sheng-hua.Cataclastic characteristics and formation mechanism of the rock mass in sliding zone of Daguangbao landslide[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(1):1-15.
[16]CUI S H,PEI X J,HUANG R Q.Effects of geological and tectonic characteristics on the earthquake-triggered Daguangbao landslide,China[J].Landslides,2017(8):1-19.
[17]张晓超,黄润秋,许模,等.石碑塬滑坡黄土液化特征及其影响因素研究[J].岩土力学,2014,35(3):801-810.ZHANG Xiao-chao,HUANG Run-qiu,XU Mo,et al.Loess liquefaction characteristics and its influential factors of Shibeiyuan landslide[J].Rock and Soil Mechanics,2014,35(3):801-810.
[18]张开健,孙红,牛富俊,等.多年冻土区缓倾角土层斜坡的地震反应[J].岩土力学,2017,38(12):3469-3474.ZHANG Kai-jian,SUN Hong,NIU Fu-jun,et al.Seismic response of low-angle soil slope in permafrost regions[J].Rock and Soil Mechanics,2017,38(12):3469-3474.
[19]孙萍,殷跃平,吴树仁,等.东河口滑坡岩石微观结构及力学性质试验研究[J].岩石力学与工程学报,2010,29(增刊1):2872-2878.SUN Ping,YIN Yue-ping,WU Shu-ren,et al.Experimental study of microstructure and mechanical properties of rocks from Donghekou landslide[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(Suppl.1):2872-2878.
[20]WANG G H,HUANG R Q,CHIGIRA M,et al.Landslide amplification by liquefaction of runout-path material after the 2008 Wenchuan(Ms 8.0)earthquake,China[J].Earth Surface Processes and Landforms,2013,38(3):265-274.
[21]CUI S H,WANG G H,PEI X J,et al.On the initiation and movement mechanisms of a catastrophic landslide triggered by the 2008 Wenchuan(Ms 8.0)earthquake in the epicenter area[J].Landslides,2017,14(3):805-819.
[22]崔圣华,裴向军,王功辉,等.基于环剪试验的汶川地震大型滑坡启动机理探索[J].岩土工程学报,2017,39(12):2268-2277.CUI Sheng-hua,PEI Xiang-jun,WANG Gong-hui,et al.The initiation of a large landslide triggered by Wenchuan earthquake:based on ring shear tests[J].Chinese Journal of Geotechnical Engineering,2017,39(12):2268-2277.
[23]朱凌,裴向军,崔圣华,等.基于动三轴试验的层间错动带动孔压特性及能量分析[J].水文地质工程地质,2017,44(5):72-79.ZHU Ling,PEI Xiang-jun,CUI Sheng-hua,et al.Dynamic pore pressure of the bedding fault material within the basal layer and energy analysis based on the triaxial test[J].Hydrogeology&Engineering Geology,2017,44(5):72-79.
[24]黄润秋,张伟锋,裴向军.大光包滑坡工程地质研究[J].工程地质学报,2014,22(4):557-585.HUANG Run-qou,ZHANG Wei-feng,PEI Xiang-jun.Engineering geological study on Daguangbao landslide[J].Journal of Engineering Geology,2014,22(4):557-585.
[25]谷川,蔡袁强,王军.地震P波和S波耦合的变围压动三轴试验模拟[J].岩土工程学报,2012,34(10):1903-1909.GU Chuan,CAI Yuan-qiang,WANG Jun.Coupling effects of P-waves and S-waves based on cyclic triaxial tests with cyclic confining pressure[J].Chinese Journal of Geotechnical Engineering,2012,34(10):1903-1909.
[26]孙磊,蔡袁强,王军,等.循环围压对饱和软黏土永久变形的影响[J].岩土力学,2015,36(2):437-443.SUN Lei,CAI Yuan-qiang,WANG Jun,et al.Effects of cyclic confining pressure on permanent deformation of saturated soft clay[J].Rock and Soil Mechanics,2015,36(2):437-443.
[27]CASTRO G.Liquefaction of sands[R].Cambridge:Harvard University,1969.
[28]吕玺琳,赖海波,黄茂松.饱和土体静态液化失稳理论预测[J].岩土力学,2014,35(5):1329-1333+1339.LüXi-lin,LAI Hai-bo,HUANG Mao-song.Theoretically predicting instability of static liquefaction of saturated soils[J].Rock and Soil Mechanics,2014,35(5):1329-1333+1339.
[29]朱建群,孔令伟,钟方杰.南京砂强度特征与静态液化现象分析[J].岩土力学,2008,27(6):1461-1465+1470.ZHU Jian-qun,KONG Ling-wei,ZHONG Fang-jie.Analysis of strength characteristics of Nanjing sand and mechanism of static liquefaction[J].Rock and Soil Mechanics,2008,27(6):1461-1465+1470.
[30]SEED H B,LYSMER J,MARTIN P P.Pore-water pressure changes during soil liquefaction[J].Journal of the Geotechnical Engineering Division,1976,102(4):323-346.
[31]牛琪瑛,张素姣.地基土液化机理的研究[J].太原理工大学学报,2002,33(3):246-248+256.NIU Qi-ying,ZHANG Su-jiao.Study on the mechanism of liquefaction of foundation soil[J].Journal of Taiyuan University of Technology,2002,33(3):246-248+256.
[32]陈国兴.岩土地震工程学[M].北京:科学出版社,2007.CHENG Guo-xin.Geotechnical earthquake engineering[M].Beijing:Science Press,2007.
[33]王洪瑾,沈瑞福,马奇国.双向振动下土的动强度[J].清华大学学报(自然科学版),1996,36(4):93-98.WANG Hong-jin,SHEN Rui-fu,MA Qi-guo.Dynamic strength of soil under multi-direction loading[J].Journal of Tsinghua University(Sci.&Tech.),1996,36(4):93-98.
[34]RASCOL E.Cyclic properties of sand:dynamic behavior for seismic applications[D].Lausanne:Swiss Federal Institute of Technology in Lausanne,2009.
[2]BURCHFIEL B C,ROYDEN L H,VAN DER HILST RD,et al.A geological and geophysical context for the Wenchuan earthquake of 12 May 2008,Sichuan,People’s Republic of China[J].GSA Today.2008,18(7):4-11.
[3]LI Y Q,JIA D,SHAW J H,et al.Structural interpretation of the coseismic faults of the Wenchuan earthquake:three-dimensional modeling of the Longmen Shan fold-and-thrust belt[J].Journal of Geophysical Research,2010,115(B04317):1-26.
[4]GORUM T,FAN X M,VAN WESTEN C J,et al.Distribution pattern of earthquake-induced landslides triggered by the 12 May 2008 Wenchuan earthquake[J].Geomorphology,2011,133(3):152-167.
[5]DAI F C,XU C,YAO X,et al.Spatial distribution of landslides triggered by the 2008 Ms 8.0 Wenchuan earthquake,China[J].Journal of Asian Earth Sciences,2011,40(4):883-895
[6]许强,李为乐.汶川地震诱发大型滑坡分布规律研究[J].工程地质学报,2010,18(6):818-826.XU Qiang,LI Wei-le.Distribution of large-scale landslides induced by the Wenchuan earthquake[J].Journal of Engineering Geology,2010,18(6):818-826.
[7]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 Run-qiu,PEI Xiang-jun,LI Tian-bin.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.
[8]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):1969-1982.YIN Yue-ping,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.
[9]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,2013,2:269-281.XU Xiang-ning,LI Sheng-wei,WANG Xiao-qun,et al.Characteristics of formation mechanism and kinematics of Daguangbaolandslide caused by Wenchuan earthquake,Sichuan,China[J].Journal of Engineering Geology,2013,2:269-281.
[10]ZHANG H,LIU S G,WANG W,et al.A new DDAmodel for kinematic analyses of rockslides on complex3-D terrain[J].Bulletin of Engineering Geology&the Environment,2016:1-17.
[11]SONG Y,HUANG D,CEN D.Numerical modeling of the 2008 Wenchuan earthquake-triggered Daguangbao landslide using a velocity and displacement dependent friction law[J].Engineering Geology,2016,215:50-68.
[12]WU J H,DO T N,CHEN C H,et al.New geometric restriction for the displacement-constraint points in discontinuous deformation analysis[J].International Journal of Geomechanics.2016,17(5):E4016002.
[13]裴向军,黄润秋,崔圣华,等.大光包滑坡岩体碎裂特征及其工程地质意义[J].岩石力学与工程学报,2015,34(增刊1):3106-3115.PEI Xiang-jun,HUANG Run-qiu,CUI Sheng-hua,et al.The rock mass cataclastic characteristics of Daguangbao landslide and its engineering geological significance[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Suppl.1):3106-3115.
[14]YANG C M,CHENG H Y,TSAO C C,et al.The kinematics and initiation mechanisms of the earthquake-triggered Daguangbao landslide[C]//EGUGeneral Assembly Conference.EGU General Aseembly Conference Abstracts.[S.l.]:[s.n.].2015.
[15]黄润秋,裴向军,崔圣华.大光包滑坡滑带岩体碎裂特征及其形成机制研究[J].岩石力学与工程学报,2016,35(1):1-15.HUANG Run-qiu,PEI Xiang-jun,CUI Sheng-hua.Cataclastic characteristics and formation mechanism of the rock mass in sliding zone of Daguangbao landslide[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(1):1-15.
[16]CUI S H,PEI X J,HUANG R Q.Effects of geological and tectonic characteristics on the earthquake-triggered Daguangbao landslide,China[J].Landslides,2017(8):1-19.
[17]张晓超,黄润秋,许模,等.石碑塬滑坡黄土液化特征及其影响因素研究[J].岩土力学,2014,35(3):801-810.ZHANG Xiao-chao,HUANG Run-qiu,XU Mo,et al.Loess liquefaction characteristics and its influential factors of Shibeiyuan landslide[J].Rock and Soil Mechanics,2014,35(3):801-810.
[18]张开健,孙红,牛富俊,等.多年冻土区缓倾角土层斜坡的地震反应[J].岩土力学,2017,38(12):3469-3474.ZHANG Kai-jian,SUN Hong,NIU Fu-jun,et al.Seismic response of low-angle soil slope in permafrost regions[J].Rock and Soil Mechanics,2017,38(12):3469-3474.
[19]孙萍,殷跃平,吴树仁,等.东河口滑坡岩石微观结构及力学性质试验研究[J].岩石力学与工程学报,2010,29(增刊1):2872-2878.SUN Ping,YIN Yue-ping,WU Shu-ren,et al.Experimental study of microstructure and mechanical properties of rocks from Donghekou landslide[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(Suppl.1):2872-2878.
[20]WANG G H,HUANG R Q,CHIGIRA M,et al.Landslide amplification by liquefaction of runout-path material after the 2008 Wenchuan(Ms 8.0)earthquake,China[J].Earth Surface Processes and Landforms,2013,38(3):265-274.
[21]CUI S H,WANG G H,PEI X J,et al.On the initiation and movement mechanisms of a catastrophic landslide triggered by the 2008 Wenchuan(Ms 8.0)earthquake in the epicenter area[J].Landslides,2017,14(3):805-819.
[22]崔圣华,裴向军,王功辉,等.基于环剪试验的汶川地震大型滑坡启动机理探索[J].岩土工程学报,2017,39(12):2268-2277.CUI Sheng-hua,PEI Xiang-jun,WANG Gong-hui,et al.The initiation of a large landslide triggered by Wenchuan earthquake:based on ring shear tests[J].Chinese Journal of Geotechnical Engineering,2017,39(12):2268-2277.
[23]朱凌,裴向军,崔圣华,等.基于动三轴试验的层间错动带动孔压特性及能量分析[J].水文地质工程地质,2017,44(5):72-79.ZHU Ling,PEI Xiang-jun,CUI Sheng-hua,et al.Dynamic pore pressure of the bedding fault material within the basal layer and energy analysis based on the triaxial test[J].Hydrogeology&Engineering Geology,2017,44(5):72-79.
[24]黄润秋,张伟锋,裴向军.大光包滑坡工程地质研究[J].工程地质学报,2014,22(4):557-585.HUANG Run-qou,ZHANG Wei-feng,PEI Xiang-jun.Engineering geological study on Daguangbao landslide[J].Journal of Engineering Geology,2014,22(4):557-585.
[25]谷川,蔡袁强,王军.地震P波和S波耦合的变围压动三轴试验模拟[J].岩土工程学报,2012,34(10):1903-1909.GU Chuan,CAI Yuan-qiang,WANG Jun.Coupling effects of P-waves and S-waves based on cyclic triaxial tests with cyclic confining pressure[J].Chinese Journal of Geotechnical Engineering,2012,34(10):1903-1909.
[26]孙磊,蔡袁强,王军,等.循环围压对饱和软黏土永久变形的影响[J].岩土力学,2015,36(2):437-443.SUN Lei,CAI Yuan-qiang,WANG Jun,et al.Effects of cyclic confining pressure on permanent deformation of saturated soft clay[J].Rock and Soil Mechanics,2015,36(2):437-443.
[27]CASTRO G.Liquefaction of sands[R].Cambridge:Harvard University,1969.
[28]吕玺琳,赖海波,黄茂松.饱和土体静态液化失稳理论预测[J].岩土力学,2014,35(5):1329-1333+1339.LüXi-lin,LAI Hai-bo,HUANG Mao-song.Theoretically predicting instability of static liquefaction of saturated soils[J].Rock and Soil Mechanics,2014,35(5):1329-1333+1339.
[29]朱建群,孔令伟,钟方杰.南京砂强度特征与静态液化现象分析[J].岩土力学,2008,27(6):1461-1465+1470.ZHU Jian-qun,KONG Ling-wei,ZHONG Fang-jie.Analysis of strength characteristics of Nanjing sand and mechanism of static liquefaction[J].Rock and Soil Mechanics,2008,27(6):1461-1465+1470.
[30]SEED H B,LYSMER J,MARTIN P P.Pore-water pressure changes during soil liquefaction[J].Journal of the Geotechnical Engineering Division,1976,102(4):323-346.
[31]牛琪瑛,张素姣.地基土液化机理的研究[J].太原理工大学学报,2002,33(3):246-248+256.NIU Qi-ying,ZHANG Su-jiao.Study on the mechanism of liquefaction of foundation soil[J].Journal of Taiyuan University of Technology,2002,33(3):246-248+256.
[32]陈国兴.岩土地震工程学[M].北京:科学出版社,2007.CHENG Guo-xin.Geotechnical earthquake engineering[M].Beijing:Science Press,2007.
[33]王洪瑾,沈瑞福,马奇国.双向振动下土的动强度[J].清华大学学报(自然科学版),1996,36(4):93-98.WANG Hong-jin,SHEN Rui-fu,MA Qi-guo.Dynamic strength of soil under multi-direction loading[J].Journal of Tsinghua University(Sci.&Tech.),1996,36(4):93-98.
[34]RASCOL E.Cyclic properties of sand:dynamic behavior for seismic applications[D].Lausanne:Swiss Federal Institute of Technology in Lausanne,2009.