顺层岩质边坡地震动力响应及地震动参数影响研究
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摘要
利用FLAC2D建立顺层岩质边坡模型,分析其在地震作用下的动力响应规律,研究地震动参数对其动力响应的影响。结果表明:顺层岩质边坡在地震作用下失稳主要由结构面控制,位移主要发生在潜在滑移面上部岩体中;对地震波存在垂直向和临空面放大作用,其滤波作用没有土质边坡明显,不同岩层会对某一频率的波产生明显的放大效应;当振幅、卓越频率增加时,坡肩下方的加速度放大系数呈递减趋势,且在强度相对较低的岩体内较明显,但随着振幅增加,边坡动力响应增强;各处加速度放大系数受地震动持时影响较小,剪应变增量受其影响较大。当振幅、持时增加时,边坡位移呈增大趋势;当卓越频率增大时,边坡位移减小。同时,证实了地震边坡破坏由上部拉破坏与下部剪切破坏组成,研究结果有助于进一步揭示边坡在地震作用下的失稳机制。
A model of bedding rock slope is established using FLAC2D program,and the dynamic response laws and the influence of parameters of ground motion on the dynamic responses under earthquake action are analyzed.It is shown that the structural surface plays a main control role on the failure of bedding rock slopes,displacement mainly takes place in the rock mass which on the potential sliding surface.The seismic waves are amplified by the vertical direction and free face of the slopes;and the filter function of bedding rock slope is not as apparent as soil slope.Different rock formations produce a significant amplification at certain frequency.The amplification coefficients of acceleration below the crest of slope decrease when the amplitudes and frequencies of seismic waves increase.The phenomenon is obvious in rock mass with relatively low intensity,but the dynamic response of slope becomes serious.The amplification coefficients of acceleration are less affected by the duration,while the duration has a great influence on the shear strain increment.The maximum displacement of the slope evidently increases with the increasing amplitudes and duration of earthquakes ground motion,while the maximum displacement of the slope decreases with the increase of predominant frequencies.It is approved that the failure of slope under earthquake action consists of the tension failure in the upper part and the shear failure in the lower part.The study results are helpful to further researches on the mechanism of slope instability under earthquakes action.
A model of bedding rock slope is established using FLAC2D program,and the dynamic response laws and the influence of parameters of ground motion on the dynamic responses under earthquake action are analyzed.It is shown that the structural surface plays a main control role on the failure of bedding rock slopes,displacement mainly takes place in the rock mass which on the potential sliding surface.The seismic waves are amplified by the vertical direction and free face of the slopes;and the filter function of bedding rock slope is not as apparent as soil slope.Different rock formations produce a significant amplification at certain frequency.The amplification coefficients of acceleration below the crest of slope decrease when the amplitudes and frequencies of seismic waves increase.The phenomenon is obvious in rock mass with relatively low intensity,but the dynamic response of slope becomes serious.The amplification coefficients of acceleration are less affected by the duration,while the duration has a great influence on the shear strain increment.The maximum displacement of the slope evidently increases with the increasing amplitudes and duration of earthquakes ground motion,while the maximum displacement of the slope decreases with the increase of predominant frequencies.It is approved that the failure of slope under earthquake action consists of the tension failure in the upper part and the shear failure in the lower part.The study results are helpful to further researches on the mechanism of slope instability under earthquakes action.
引文
[1]刘汉龙,费康,高玉峰.边坡地震稳定时程分析方法[J].岩土力学,2003,24(4):553–556.(LIU Hanlong,FEI Kang,GAO Yufeng.Time history analysis method of slope seismic stability[J].Rock and Soil Mechanics,2003,24(4):553–556.(in Chinese))
[2]DAWSON E M,ROTH W H,DRESCHER A.Slope stability analysis by strength reduction[J].Geotechnique,1999,49(6):835–840.
[3]何蕴龙,陆述远.岩石边坡地震作用近似计算方法[J].岩土工程学报,1998,20(3):66–68.(HE Yunlong,LU Shuyuan.A method for calculating the seismic action in rock slope[J].Chinese Journal of Geotechnical Engineering,1998,20(3):66–68.(in Chinese))
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[5]张均峰,李正果.强地震荷载作用下含断层岩质边坡稳定性分析[J].力学与实践.2010,32(1):24-28.(ZHANG Junfeng,Ll Zhengguo.Stability analysis of fractured rock slope under strong seismic loading[J].Mechanics in Engineering,2010,32(1):24–28.(in Chinese))
[6]解联库,杨小聪,杨天鸿,等.顺层岩质边坡变形破坏规律的分析[J].有色金属,2007,5(2):75–78.(XIE Lianku,YANG Xiaocong,YANG Tianhong,et al.Analysis of distortion disciplinarian of bedding slope[J].Nonferrous Metals,2007,5(2):75–78.(in Chinese))
[7]余飞,陈善雄,余和平.顺层岩质边坡渐进破坏及失稳机制的数值模拟研究[J].岩土力学,2005,26(增2):36–40.(YU Fei,CHEN Shanxiong,YU Heping.Numerical simulation study on progressive destruction and failure mechanism of bedding rock slopes[J].Rock and Siol Mechanics,2005,26(Supp.2):36–40.(in Chinese))
[8]龚文惠,王平,陈峰.顺层岩质路堑边坡稳定性的敏感性因素分析[J].岩土力学,2007,28(4):812–816.(GONG Wenhui,WANG Ping,CHEN Feng.Analysis of sensitivity factors to stability of bedding rock cutting slope[J].Rock and Soil Mechanics,2007,28(4):812–816.(in Chinese))
[9]徐光兴,姚令侃,高召宁,等.边坡动力特性与动力响应的大型振动台模型试验研究[J].岩石力学与工程学报,2008,27(3):624–632.(XU Guangxing,YAO Lingkan,GAO Zhaoning,et al.Large-scale shaking table model test on the dynamic characteristics and seismic responses of slope[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(3):624–632.(in Chinese))
[10]郑颖人,叶海林,黄润秋.地震边坡破坏机制及其破裂面的分析探讨[J].岩石力学与工程学报,2009,28(8):1 714–1 723.(ZHENG Yingren,YE Hailin,HUANG Runqiu.Analysis and discussion of failure mechanism and fracture surface of slope under earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(8):1 714–1 723.(in Chinese))
[11]郑颖人,赵尚毅,张鲁渝.用有限元强度折减法进行边坡稳定分析[J].中国工程科学,2002,4(10):57–62.(ZHENG Yingren,ZHAO Shangyi,ZHANG Luyu.Slope stability analysis by strength reduction FEM[J].Engineering Science,2002,4(10):57–62.(in Chinese))
[12]徐光兴,姚令侃,李朝红,等.边坡地震动力响应规律及地震动参数影响研究[J].岩土工程学报,2008,30(6):918–923.(XU Guangxing,YAO Lingkan,LI Zhaohong,et al.Dynamic response of slopes under earthquakes and influence of ground motion parameters[J].Chinese Journal of Geotechnical Engineering,2008,30(6):918–923.(in Chinese))
[13]LIN M L,WANG K L.Seismic slope behavior in a large-scale shaking table model test[J].Engineering Geology,2006,86(2/3):118–133.
[2]DAWSON E M,ROTH W H,DRESCHER A.Slope stability analysis by strength reduction[J].Geotechnique,1999,49(6):835–840.
[3]何蕴龙,陆述远.岩石边坡地震作用近似计算方法[J].岩土工程学报,1998,20(3):66–68.(HE Yunlong,LU Shuyuan.A method for calculating the seismic action in rock slope[J].Chinese Journal of Geotechnical Engineering,1998,20(3):66–68.(in Chinese))
[4]祁生文.边坡动力响应分析及应用研究[博士学位论文][D].北京:中国科学院地质与地球物理研究所,2002.(QI Shengwen.Study on dynamic responses of slopes and its application[Ph.D.Thesis][D].Beijing:Institute of Geology and Geophysics,Chinese Academy of Sciences,2002.(in Chinese))
[5]张均峰,李正果.强地震荷载作用下含断层岩质边坡稳定性分析[J].力学与实践.2010,32(1):24-28.(ZHANG Junfeng,Ll Zhengguo.Stability analysis of fractured rock slope under strong seismic loading[J].Mechanics in Engineering,2010,32(1):24–28.(in Chinese))
[6]解联库,杨小聪,杨天鸿,等.顺层岩质边坡变形破坏规律的分析[J].有色金属,2007,5(2):75–78.(XIE Lianku,YANG Xiaocong,YANG Tianhong,et al.Analysis of distortion disciplinarian of bedding slope[J].Nonferrous Metals,2007,5(2):75–78.(in Chinese))
[7]余飞,陈善雄,余和平.顺层岩质边坡渐进破坏及失稳机制的数值模拟研究[J].岩土力学,2005,26(增2):36–40.(YU Fei,CHEN Shanxiong,YU Heping.Numerical simulation study on progressive destruction and failure mechanism of bedding rock slopes[J].Rock and Siol Mechanics,2005,26(Supp.2):36–40.(in Chinese))
[8]龚文惠,王平,陈峰.顺层岩质路堑边坡稳定性的敏感性因素分析[J].岩土力学,2007,28(4):812–816.(GONG Wenhui,WANG Ping,CHEN Feng.Analysis of sensitivity factors to stability of bedding rock cutting slope[J].Rock and Soil Mechanics,2007,28(4):812–816.(in Chinese))
[9]徐光兴,姚令侃,高召宁,等.边坡动力特性与动力响应的大型振动台模型试验研究[J].岩石力学与工程学报,2008,27(3):624–632.(XU Guangxing,YAO Lingkan,GAO Zhaoning,et al.Large-scale shaking table model test on the dynamic characteristics and seismic responses of slope[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(3):624–632.(in Chinese))
[10]郑颖人,叶海林,黄润秋.地震边坡破坏机制及其破裂面的分析探讨[J].岩石力学与工程学报,2009,28(8):1 714–1 723.(ZHENG Yingren,YE Hailin,HUANG Runqiu.Analysis and discussion of failure mechanism and fracture surface of slope under earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(8):1 714–1 723.(in Chinese))
[11]郑颖人,赵尚毅,张鲁渝.用有限元强度折减法进行边坡稳定分析[J].中国工程科学,2002,4(10):57–62.(ZHENG Yingren,ZHAO Shangyi,ZHANG Luyu.Slope stability analysis by strength reduction FEM[J].Engineering Science,2002,4(10):57–62.(in Chinese))
[12]徐光兴,姚令侃,李朝红,等.边坡地震动力响应规律及地震动参数影响研究[J].岩土工程学报,2008,30(6):918–923.(XU Guangxing,YAO Lingkan,LI Zhaohong,et al.Dynamic response of slopes under earthquakes and influence of ground motion parameters[J].Chinese Journal of Geotechnical Engineering,2008,30(6):918–923.(in Chinese))
[13]LIN M L,WANG K L.Seismic slope behavior in a large-scale shaking table model test[J].Engineering Geology,2006,86(2/3):118–133.
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