岩性及岩体结构对斜坡地震加速度响应的影响
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摘要
斜坡岩体的岩性及岩体结构是斜坡在地震作用下产生变形破坏的主要控制因素。基于振动台模型试验,对4个斜坡模型探讨了这2个因素对斜坡地震动力响应的影响。岩性包括强度相对较高的硬岩和强度相对较低的软岩,对这两种岩性的斜坡又分别考虑了不含结构面的均质斜坡和含水平层状结构面的斜坡。基于传感器采集到的大量数据,以主频相近的天然地震波和10 Hz正弦波加载为分析工况,获得了以下几点认识:(1)4个模型斜坡坡面和坡内的水平向加速度均具有高程放大效应,尤其是软岩斜坡坡顶放大效应最显著;(2)软岩斜坡对水平向加速度的高程放大效应强于硬岩斜坡,尤其是在均质斜坡中表现最显著,均质软岩斜坡的高程放大效应呈现出明显的非线性特征;(3)当加载方向与水平层面平行时,含水平层状结构面的斜坡比均质斜坡产生了更强的高程放大效应,且在软岩斜坡中体现最显著;(4)岩性差异对斜坡水平向加速度高程效应的影响比结构差异的影响更为显著。研究结果为岩质斜坡的抗震设计提供了一定参考。
Lithology and rock structure of a rock slope are two of the most important controlling factors on its deformation and failure process during earthquake.Four shaking table models of slopes are designed to explore the effects of the above two factors on slope seismic responses.Referring to lithology,hard rock with high strength and soft rock with low strength are modeled,at the same time,an isotropic slope and a horizontally layered slope are selected for each kind of lithology.Based on a large number of sensor recordings,results are analyzed under excitations of both the real waves and sine waves which have the similar predominant frequency.The main conclusions are drawn as follows:(1) The horizontal accelerations on the slope surface and inside the slope demonstrate topographic amplification effect for all the 4 model slopes;and the maximum amplification factor occuring at the crest of the soft rock slope model;(2) The topographic effects in soft rock slopes are stronger than those in hard rock slopes,which is more obvious in the two isotropic rock slopes,and the topographic effect in the isotropic and soft rock slope depict nonlinear change laws.(3) When the shaking direction accords with the horizontal structure surface just as in the present study,the layered slopes demonstrate stronger topographic amplification effect for horizontal accelerations,especially in soft rock slopes;(4) Lithology plays a more important role in topographic effect than discontinuity in a rock slope during earthquake.The results provide a reference for the seismic design of rock slopes.
Lithology and rock structure of a rock slope are two of the most important controlling factors on its deformation and failure process during earthquake.Four shaking table models of slopes are designed to explore the effects of the above two factors on slope seismic responses.Referring to lithology,hard rock with high strength and soft rock with low strength are modeled,at the same time,an isotropic slope and a horizontally layered slope are selected for each kind of lithology.Based on a large number of sensor recordings,results are analyzed under excitations of both the real waves and sine waves which have the similar predominant frequency.The main conclusions are drawn as follows:(1) The horizontal accelerations on the slope surface and inside the slope demonstrate topographic amplification effect for all the 4 model slopes;and the maximum amplification factor occuring at the crest of the soft rock slope model;(2) The topographic effects in soft rock slopes are stronger than those in hard rock slopes,which is more obvious in the two isotropic rock slopes,and the topographic effect in the isotropic and soft rock slope depict nonlinear change laws.(3) When the shaking direction accords with the horizontal structure surface just as in the present study,the layered slopes demonstrate stronger topographic amplification effect for horizontal accelerations,especially in soft rock slopes;(4) Lithology plays a more important role in topographic effect than discontinuity in a rock slope during earthquake.The results provide a reference for the seismic design of rock slopes.
引文
[1]黄润秋,李为乐.“5·12”汶川大地震触发地质灾害的发育分布规律研究[J].岩石力学与工程学报,2008,27(12):2585-2592.HUANG Run-qiu,LI Wei-le.Research on development and distribution rules of geohazards induced by Wenchuan earthquake on 12th May,2008[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(12):2585-2592.
[2]许强.汶川大地震诱发地质灾害主要类型与特征研究[J].地质灾害与环境保护,2009,20(2):86-93.XU Qiang.Main types and characteristics of the geo-hazards triggered by the Wenchuan earthquake[J].Journal of Geological Hazards and Environment Preservation,2009,20(2):86-93.
[3]YIN YUEPING,WANG FAWU,SUN PING.Landslide hazards triggered by the 2008 Wenchuan earthquake,Sichuan,China[J].Landslides,2009,6(2):139-152.
[4]CHIGIRA MASAHIRO,WU XIYONG,INOKUCHI TAKASHI,et al.Landslides induced by the 2008 Wenchuan earthquake,Sichuan,China[J].Geomorphology,2010,118(3-4):225-238.
[5]黄润秋.汶川8.0级地震触发崩滑灾害机制及其地质力学模式[J].岩石力学与工程学报,2009,28(6):12391249.HUANG Run-qiu.Mechanism and geomechanical modes of landslide hazards triggered by Wenchuan 8.0 earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(6):1239-1249.
[6]TANG HUIMING,JIA HONGBIAO,HU XINLI,et al.Characteristics of landslides induced by the great Wenchuan earthquake[J].Journal of Earth Science,2010,21(1):104-113.
[7]QI SHENGWEN,XU QIANG,ZHANG BING,et al.Source characteristics of long runout rock avalanches triggered by the 2008 Wenchuan earthquake,China[J].Journal of Asian Earth Science,2011,40(4):896-906.
[8]WANG ZIFA.A preliminary report on the great Wenchuan earthquake[J].Earthquake Engineering and Engineering Vibration,2008,7(2):225-234.
[9]HARP E L,JIBSON R W.Anomalous concentrations of seismically triggered rock falls in Pacoima canyon:are they caused by highly susceptible slopes or local amplification of seismic shaking?[J].Bulletin of the Seismological Society of America,2002,92(8):31803189.
[10]KEEFER D K.Landslides caused by earthquakes[J].Geological Society of America Bulletin,1984,95(4):406-421.
[11]TUCKER B E,KING J L,HATZFELD D,et al.Observations of hard-rock site effects[J].Bulletin of the Seismological Society of America,1984,74(1):121136.
[12]SEPúLVEDA S A,MURPHY W,PETLEY D N.Topographic controls on coseismic rock slides during the 1999 Chi-chi earthquake,Taiwan[J].Quarterly Journal of Engineering Geology and Hydrogeology,2005,38(2):189-196.
[13]梁庆国,韩文峰,马润勇,等.强地震动作用下层状岩体破坏的物理模拟研究[J].岩土力学,2005,26(8):1307-1311.LIANG Qing-guo,HAN Wen-feng,MA Run-yong,et al.Physical simulation study on dynamic failures of layered rock masses under strong ground motion[J].Rock and Soil Mechanics,2005,26(8):1307-1311.
[14]艾畅,冯春,李世海,等.地震作用下顺层岩质边坡动力响应的试验研究[J].岩石力学与工程学报,2010,29(9):1825-1832.AI Chang,FENG Chun,LI Shi-hai,et al.Experimental research on dynamic response of consequent rock slope under seismic loading[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(9):1825-1832.
[15]王思敬.论岩石的地质本质性及其岩石力学演绎[J].岩石力学与工程学报,2009,28(3):433-450.WANG Si-jing.Geological nature of rock and its deduction for rock mechanics[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(3):433450.
[16]许强,刘汉香,邹威,等.斜坡加速度动力响应特性的大型振动台试验研究[J].岩石力学与工程学报,2010,29(12):2420-2428.XU Qiang,LIU Han-xiang,ZOU Wei,et al.Study on slope dynamic responses of accelerations by large-scale shaking table test[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(12):2420-2428.
[17]刘汉香,许强,范宣梅,等.地震动强度对斜坡加速度动力响应规律的影响[J].岩土力学,2012,33(5):1357-1365.LIU Han-xiang,XU Qiang,FAN Xuan-mei.Influence of ground motion intensity on dynamic response laws of slope accelerations[J].Rock and Soil Mechanics,2012,33(5):1357-1365.
[18]邹威,许强,刘汉香.强震作用下岩质斜坡动力响应特性的大型振动台试验方案设计[J].地质灾害与环境保护,2011,22(1):87-91.ZOU Wei,XU Qiang,LIU Han-xiang,et al.Designing the model for testing the dynamic response of rock slopes[J].Journal of Geological Hazards and Environment Preservation,2011,22(1):87-91.
[2]许强.汶川大地震诱发地质灾害主要类型与特征研究[J].地质灾害与环境保护,2009,20(2):86-93.XU Qiang.Main types and characteristics of the geo-hazards triggered by the Wenchuan earthquake[J].Journal of Geological Hazards and Environment Preservation,2009,20(2):86-93.
[3]YIN YUEPING,WANG FAWU,SUN PING.Landslide hazards triggered by the 2008 Wenchuan earthquake,Sichuan,China[J].Landslides,2009,6(2):139-152.
[4]CHIGIRA MASAHIRO,WU XIYONG,INOKUCHI TAKASHI,et al.Landslides induced by the 2008 Wenchuan earthquake,Sichuan,China[J].Geomorphology,2010,118(3-4):225-238.
[5]黄润秋.汶川8.0级地震触发崩滑灾害机制及其地质力学模式[J].岩石力学与工程学报,2009,28(6):12391249.HUANG Run-qiu.Mechanism and geomechanical modes of landslide hazards triggered by Wenchuan 8.0 earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(6):1239-1249.
[6]TANG HUIMING,JIA HONGBIAO,HU XINLI,et al.Characteristics of landslides induced by the great Wenchuan earthquake[J].Journal of Earth Science,2010,21(1):104-113.
[7]QI SHENGWEN,XU QIANG,ZHANG BING,et al.Source characteristics of long runout rock avalanches triggered by the 2008 Wenchuan earthquake,China[J].Journal of Asian Earth Science,2011,40(4):896-906.
[8]WANG ZIFA.A preliminary report on the great Wenchuan earthquake[J].Earthquake Engineering and Engineering Vibration,2008,7(2):225-234.
[9]HARP E L,JIBSON R W.Anomalous concentrations of seismically triggered rock falls in Pacoima canyon:are they caused by highly susceptible slopes or local amplification of seismic shaking?[J].Bulletin of the Seismological Society of America,2002,92(8):31803189.
[10]KEEFER D K.Landslides caused by earthquakes[J].Geological Society of America Bulletin,1984,95(4):406-421.
[11]TUCKER B E,KING J L,HATZFELD D,et al.Observations of hard-rock site effects[J].Bulletin of the Seismological Society of America,1984,74(1):121136.
[12]SEPúLVEDA S A,MURPHY W,PETLEY D N.Topographic controls on coseismic rock slides during the 1999 Chi-chi earthquake,Taiwan[J].Quarterly Journal of Engineering Geology and Hydrogeology,2005,38(2):189-196.
[13]梁庆国,韩文峰,马润勇,等.强地震动作用下层状岩体破坏的物理模拟研究[J].岩土力学,2005,26(8):1307-1311.LIANG Qing-guo,HAN Wen-feng,MA Run-yong,et al.Physical simulation study on dynamic failures of layered rock masses under strong ground motion[J].Rock and Soil Mechanics,2005,26(8):1307-1311.
[14]艾畅,冯春,李世海,等.地震作用下顺层岩质边坡动力响应的试验研究[J].岩石力学与工程学报,2010,29(9):1825-1832.AI Chang,FENG Chun,LI Shi-hai,et al.Experimental research on dynamic response of consequent rock slope under seismic loading[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(9):1825-1832.
[15]王思敬.论岩石的地质本质性及其岩石力学演绎[J].岩石力学与工程学报,2009,28(3):433-450.WANG Si-jing.Geological nature of rock and its deduction for rock mechanics[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(3):433450.
[16]许强,刘汉香,邹威,等.斜坡加速度动力响应特性的大型振动台试验研究[J].岩石力学与工程学报,2010,29(12):2420-2428.XU Qiang,LIU Han-xiang,ZOU Wei,et al.Study on slope dynamic responses of accelerations by large-scale shaking table test[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(12):2420-2428.
[17]刘汉香,许强,范宣梅,等.地震动强度对斜坡加速度动力响应规律的影响[J].岩土力学,2012,33(5):1357-1365.LIU Han-xiang,XU Qiang,FAN Xuan-mei.Influence of ground motion intensity on dynamic response laws of slope accelerations[J].Rock and Soil Mechanics,2012,33(5):1357-1365.
[18]邹威,许强,刘汉香.强震作用下岩质斜坡动力响应特性的大型振动台试验方案设计[J].地质灾害与环境保护,2011,22(1):87-91.ZOU Wei,XU Qiang,LIU Han-xiang,et al.Designing the model for testing the dynamic response of rock slopes[J].Journal of Geological Hazards and Environment Preservation,2011,22(1):87-91.
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