地震作用下顺层岩质边坡动力响应规律及变形机制研究
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摘要
运用有限差分软件FLAC3D,建立了某一含软弱夹层的顺层岩质边坡三维模型,首先对其在地震作用下的响应规律进行了研究,然后通过塑性区、位移时程,以及关键单元剪应变增量的变化分析了其变形机制。计算表明:地震作用下顺层岩质边坡坡面点水平向和垂向加速度峰值放大系数随高程增加均呈增大趋势,在结构面及坡顶处增幅较大;边坡顶点水平向和垂向加速度峰值放大系数自坡内向坡面方向呈增大趋势,在结构面处增幅较大;岩体对输入地震波存在垂直放大效应,其滤波作用没有土质边坡明显;顺层岩质边坡变形破坏主要受软弱夹层控制,表现为软弱结构面上部拉破坏与下部剪切破坏;给出了顺层岩质边坡滑移面位置的确定方法以及边坡失稳判定方法。研究结果对顺层岩质边坡动力作用下稳定性分析及抗震设计具有一定指导意义。
Seismic slope dynamic response and the deformation mechanism are the premises of analyzing the dynamic stability of slopes.The response regulation of a bedding rock slope under the seismic action is discussed by using the three-dimensional finite difference software FLAC3D.The deformation mechanism is analyzed through the plastic zone,displacement time-histories as well as changes of shear strain increment of key elements.The calculation shows that,under the seismic action,the amplification coefficients of the horizontal and vertical peak accelerations of the bedding rock slopes increase with the increasing elevation and come to the maximum at the structural plane and the top of the slope;those at the top of the slope increase with the decrease of the distance from the slope surface and come to the maximum at the structural plane;the rock mass has vertical amplification effect on the input seismic waves and its filtering effect is inferior to the soil slope;the deformation damage of rock slopes mainly comes from the weak structural plane,formed by upper tension failure and bottom shear failure;the research also gives the methods of determining the position of the sliding surface of bedding rock slope's and the judgment of slope instability.The results of the research have certain significance to analyzing the stability of bedding rock slopes and seismic design.
Seismic slope dynamic response and the deformation mechanism are the premises of analyzing the dynamic stability of slopes.The response regulation of a bedding rock slope under the seismic action is discussed by using the three-dimensional finite difference software FLAC3D.The deformation mechanism is analyzed through the plastic zone,displacement time-histories as well as changes of shear strain increment of key elements.The calculation shows that,under the seismic action,the amplification coefficients of the horizontal and vertical peak accelerations of the bedding rock slopes increase with the increasing elevation and come to the maximum at the structural plane and the top of the slope;those at the top of the slope increase with the decrease of the distance from the slope surface and come to the maximum at the structural plane;the rock mass has vertical amplification effect on the input seismic waves and its filtering effect is inferior to the soil slope;the deformation damage of rock slopes mainly comes from the weak structural plane,formed by upper tension failure and bottom shear failure;the research also gives the methods of determining the position of the sliding surface of bedding rock slope's and the judgment of slope instability.The results of the research have certain significance to analyzing the stability of bedding rock slopes and seismic design.
引文
[1]李海波,肖克强,刘亚群.地震荷载作用下顺层岩质边坡安全系数分析[J].岩石力学与工程学报,2007,26(12):2385–2394.(LI Hai-bo,XIAO Ke-qiang,LIU Ya-qun.Factor of safety analysis of bedding rock slope under seismicload[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(12):2385–2394.(in Chinese))
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[8]唐洪祥,邵龙潭.地震动力作用下有限元土石坝边坡稳定分析[J].岩石力学与工程学报,2004,23(8):1318–1324.(TANG Hong-xiang,SHAO Long-tan.Finite elementanalysis on slope stability of earth-rockdam underearthquakes[J].Chinese Journal of Rock Mechanics andEngineering,2004,23(8):1318–1324.(in Chinese))
[9]祁生文.单面边坡的两种动力反应形式及其临界高度[J].地球物理学报,2006,49(2):518–523.(QI Sheng-wen.Twopatterns of dynamic responses of single-free-surface slopesand their threshold height[J].Chinese Journal of Geophysics,2006,49(2):518–523.(in Chinese))
[10]胡聿贤.地震工程学[M].北京:地震出版社,1988.(HUYu-xian.Seismic enginering[M].Beijing:Earthquake Press,1988.(in Chinese))
[11]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 Guang-xing,YAO Ling-kan,LI Zhao-hong,et al.Dynamic response of slopes under earthquake and influence ofground motion parameters[J].Chinese Journal of GeotechnicalEngineering,2008,30(6):918–923.(in Chinese))
[12]黄润秋,余嘉顺.软弱夹层特性对地震波强度的影响的模拟[J].工程地质学报,2003,11(3):312–317.(HUANGRun-qiu,YU Jia-shun.Modeling of the effects of propertiesof a buried weak layer on seismic waves[J].Journal ofEngineering Geology,2003,11(3):312–317.(in Chinese))
[13]祁生文,伍法权,刘春玲,等.地震边坡稳定性的工程地质分析[J].岩石力学与工程学报,2004,23(16):2792–2797.(QI Sheng-wen,WU Fa-quan,LIU Chun-ling,et a1.Engineering geology analysis of stability of slope undereasthquake[J].Chinese Journal of RockMechanics andEngineering,2004,23(16):2792–2797.(in Chinese))
[2]殷跃平.汶川地质与滑坡灾害概论[M].北京:地质出版社,2009.(YIN Yue-ping.Introduction of seismic geology andlandslide hazard triggered by Wenchuan earthquake[M].Beijing:Geological Publishing House,2009.(in Chinese))
[3]SHOU K J,WANG C F.Analysis of the chiufengershanlandslide:triggered by the 1999 Chi-Chi earthquake inTaiwan[J].Engineering Geology,2003,68(3/4):237–250.
[4]李树德,任秀生,岳升阳,等.地震滑坡研究[J].水土保持研究,2001,8(2):24–25.(LI Shu-de,REN Xiu-sheng,YUESheng-yang,et al.Study on earthquake-landslide[J].Research of Soil and Water Conservation,2001,8(2):24–25.(in Chinese))
[5]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):1714–1723.(ZHENG Ying-ren,YE Hai-lin,HUANG Run-qiu.Analysis and discussion of failure mechanism and fracturesurface of slope under earthquake[J].Chinese Journal ofRock Mechanics and Engineering,2009,28(8):1714–1723.(in Chinese))
[6]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.(ZHENGYing-ren,ZHAO Shang-yi,ZHANG Lu-yu.Slope stabilityanalysis by strength reduction FEM[J].Engineering Science,2002,4(10):57–62.(in Chinese))
[7]毕忠伟,张明,金峰,等.地震作用下边坡的动态响应规律研究[J].岩土力学,2009,30(增刊):180–183.(BIZhong-wei,ZHANG Ming,JIN Feng,et al.Dynamicresponse of slopes under earthquake[J].Rock and SoilMechanics,2009,30(S):180–183.(in Chinese))
[8]唐洪祥,邵龙潭.地震动力作用下有限元土石坝边坡稳定分析[J].岩石力学与工程学报,2004,23(8):1318–1324.(TANG Hong-xiang,SHAO Long-tan.Finite elementanalysis on slope stability of earth-rockdam underearthquakes[J].Chinese Journal of Rock Mechanics andEngineering,2004,23(8):1318–1324.(in Chinese))
[9]祁生文.单面边坡的两种动力反应形式及其临界高度[J].地球物理学报,2006,49(2):518–523.(QI Sheng-wen.Twopatterns of dynamic responses of single-free-surface slopesand their threshold height[J].Chinese Journal of Geophysics,2006,49(2):518–523.(in Chinese))
[10]胡聿贤.地震工程学[M].北京:地震出版社,1988.(HUYu-xian.Seismic enginering[M].Beijing:Earthquake Press,1988.(in Chinese))
[11]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 Guang-xing,YAO Ling-kan,LI Zhao-hong,et al.Dynamic response of slopes under earthquake and influence ofground motion parameters[J].Chinese Journal of GeotechnicalEngineering,2008,30(6):918–923.(in Chinese))
[12]黄润秋,余嘉顺.软弱夹层特性对地震波强度的影响的模拟[J].工程地质学报,2003,11(3):312–317.(HUANGRun-qiu,YU Jia-shun.Modeling of the effects of propertiesof a buried weak layer on seismic waves[J].Journal ofEngineering Geology,2003,11(3):312–317.(in Chinese))
[13]祁生文,伍法权,刘春玲,等.地震边坡稳定性的工程地质分析[J].岩石力学与工程学报,2004,23(16):2792–2797.(QI Sheng-wen,WU Fa-quan,LIU Chun-ling,et a1.Engineering geology analysis of stability of slope undereasthquake[J].Chinese Journal of RockMechanics andEngineering,2004,23(16):2792–2797.(in Chinese))
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