黄土边坡动力响应的影响效应研究
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摘要
根据随机地震荷载作用下黄土动三轴试验的动剪切模量表达式和试验参数编制子程序,采用MSC.Marc软件建立有限元模型,并基于人工合成地震动时程对黄土边坡进行动力响应分析,研究输入地震波的卓越频率、幅值以及入射角变化,对黄土边坡位移、速度、应力的动力响应,分析对响应幅值、频谱的影响效应。由研究结果可见:边坡位移、速度等响应时程的卓越频率远小于地震输入波的卓越频率,边坡岩土介质对地震波的高频成分有过滤或吸收作用;边坡的动力响应幅值极大的受地震输入波卓越频率的影响,对于给定的边坡,它将对包含某一卓越频率成分的地震动时程的动力响应异常强烈;输入地震波幅值的变化,只引起边坡动力响应幅值的线性变化,不改变边坡中响应时程的频谱特征;当地震波以一定角度入射时,边坡动力应力响应时程包含了更多的高频成分,位移和速度响应幅值随入射角的增大而减小,且越靠近坡顶减速越快,而应力响应幅值在坡顶与坡腰、坡脚处具有不同的影响规律;另外,地震荷载作用方向的改变,还对边坡动力响应放大系数有较大影响,当作用力方向非竖直时,动力响应放大系数随地震波入射角的增大而减小。
This paper is based on dynamic shear modulus formula and correlative parameters of loess gained from three triaxial tests.The tests were acted by random seismic load.A subprogram of MSC.Marc was programmed.Finite element model acted by artificial earthquake wave was built to study dynamic response of loess slope.So,the displacement,velocity and stress transformation law of loess slope were analyzed when excellent frequency,amplitude and action direction of input seismic wave was changed.The results show that excellent frequency of slope displacement,velocity response time-history is much smaller than the input wave.A large number of high frequency wave was filtered when seismic wave transmit in slope soil.And dynamic response of loess slope was affected by the predominant frequency of seismic wave strongly.A giving slope was exceptional sensitive to certain seismic wave with predominant frequency.In addition,the changing of amplitude of seismic wave could alter the dynamic response amplitude of slope linearly,but couldn't transform the spectrum character of dynamic response of slope.The result also shows that the dynamic response time-history of slope contains more high frequency components when acting earthquake wave with certain action angle.Response amplitude of displacement and velocity reduced more quickly more close to the top when action angle increasing.Different effect law of stress response amplitude was shown in the top,middle and toe of slope.The changing of seismic wave acting direction affects dynamic response amplificatory coefficient also,which decreases with the increase of seismic wave acting angle when direction is un-vertical.
This paper is based on dynamic shear modulus formula and correlative parameters of loess gained from three triaxial tests.The tests were acted by random seismic load.A subprogram of MSC.Marc was programmed.Finite element model acted by artificial earthquake wave was built to study dynamic response of loess slope.So,the displacement,velocity and stress transformation law of loess slope were analyzed when excellent frequency,amplitude and action direction of input seismic wave was changed.The results show that excellent frequency of slope displacement,velocity response time-history is much smaller than the input wave.A large number of high frequency wave was filtered when seismic wave transmit in slope soil.And dynamic response of loess slope was affected by the predominant frequency of seismic wave strongly.A giving slope was exceptional sensitive to certain seismic wave with predominant frequency.In addition,the changing of amplitude of seismic wave could alter the dynamic response amplitude of slope linearly,but couldn't transform the spectrum character of dynamic response of slope.The result also shows that the dynamic response time-history of slope contains more high frequency components when acting earthquake wave with certain action angle.Response amplitude of displacement and velocity reduced more quickly more close to the top when action angle increasing.Different effect law of stress response amplitude was shown in the top,middle and toe of slope.The changing of seismic wave acting direction affects dynamic response amplificatory coefficient also,which decreases with the increase of seismic wave acting angle when direction is un-vertical.
引文
[1]邓龙胜.强震作用下黄土边坡的动力响应机理和动力稳定性研究[D].西安:长安大学,2010.Deng Longsheng.Study on the Response and Stability Mechanicsof Loess Slope in Environmeng of Strong Earthquake.Xi'an:Chang'an University,2010.
[2]祁生文,伍法权,孙进忠.边坡动力响应规律研究[J].中国科学(E辑),2003,33(增):28～40.Qi Shengwen,Wu Faquan,Sun Jinzhong.Study on the dynamicresponse characteristic of slope.Science in China,Ser.E,2003,33(S):28～40.
[3]艾畅,冯春,李世海,赵安平.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 Shihai,Zhao Anping.Experimental re-search on dynamic response of consequent rock slope under seismicloading.Chinese Journal of Rock Mechanics and Engineering,2010,29(9):1825～1832.
[4]姜彤,赵彦彦,王忠福.边坡动力响应的非线性特征分析[J].世界地震工程,2010,26(1):125～129.Jiang Tong,Zhao Yanyan,Wang Zhongfu.Analysis on nonlinearcharacteristics of a slope under seismic loads.World EarthquakeEngineering,2010,26(1):125～129.
[5]周永江,王开云,符文熹,何江达.高地震烈度区堆积体边坡动力响应时程特征分析[J].山地学报,2007,25(1):93～98.Zhou Yongjiang,Wang Kaiyun,Fu Wenxi,He Jiangda.Analysison time history dynamic response of a pockfall-type slope underhigh earthquake intensity.Journal of Mountan Science,2007,25(1):93～98.
[6]薄景山,徐国栋,景立平.土边坡地震反应及其动力稳定性分析[J].地震工程与工程振动,2001,21(3):116～120.Bo Jingshan,Xu Guodong,Jing Liping.Seismic response and dy-namic stability analysis of soil slopes.Earthquake Engineering andEngineering Vibration,2001,21(3):116～120.
[7]金亮星,李建.高速铁路路堑岩质边坡的动力响应分析[J].振动工程学报,2008,21(4):354～358.Jin Liangxing,Li Jian.Dynamic response analysis of cutting rockslope under high speed train vibration load.Journal of VibrationEngineering,2008,21(4):354～358.
[8]周剑,张路青,王学良.水平层状岩体边坡动力响应中的结构面效应研究[J].工程地质学报,2011,19(3):352～358.Zhou Jian,Zhang Luqing,Wang Xueliang.Effect of structuralplane on dynamic response of rock slopes with horizontal strata.Journal of Engineering Geology,2011,19(3):352～358.
[9]言志信,曹小红,张刘平,张海东.地震作用下黄土边坡动力响应数值分析[J].岩土力学,2011,(增2):610～614.Yan Zhixin,Cao Xiaohong,Zhang Liuping,Zhang Haidong.Nu-merical analysis of loess slope dynamic response under earthquake.Rock and Soil Mechanics,2011,(s2):610～614.
[10]DEL Gaudio V,Wasowski J.Advances and problems in under-standing the seismic response of potentially unstable slopes.Eng.Geol.2010,doi:10.1016/j.enggeo.2010.09.007.
[11]George D.Bouckovalas,Achilleas G.Papadomotriou.Numericalevaluation of slope topography effects on seismic ground motion.Soil Dynamics and Earthquake Engineering,2005,25(7～10):547～558.
[12]YQ Liu,HB Li,J Zhao.UDEC simulation for the dynamic re-sponse of a rock slope subject to explosions.International Journalof Rock Mechanics&Mining Sciences,2004,41:474.
[2]祁生文,伍法权,孙进忠.边坡动力响应规律研究[J].中国科学(E辑),2003,33(增):28～40.Qi Shengwen,Wu Faquan,Sun Jinzhong.Study on the dynamicresponse characteristic of slope.Science in China,Ser.E,2003,33(S):28～40.
[3]艾畅,冯春,李世海,赵安平.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 Shihai,Zhao Anping.Experimental re-search on dynamic response of consequent rock slope under seismicloading.Chinese Journal of Rock Mechanics and Engineering,2010,29(9):1825～1832.
[4]姜彤,赵彦彦,王忠福.边坡动力响应的非线性特征分析[J].世界地震工程,2010,26(1):125～129.Jiang Tong,Zhao Yanyan,Wang Zhongfu.Analysis on nonlinearcharacteristics of a slope under seismic loads.World EarthquakeEngineering,2010,26(1):125～129.
[5]周永江,王开云,符文熹,何江达.高地震烈度区堆积体边坡动力响应时程特征分析[J].山地学报,2007,25(1):93～98.Zhou Yongjiang,Wang Kaiyun,Fu Wenxi,He Jiangda.Analysison time history dynamic response of a pockfall-type slope underhigh earthquake intensity.Journal of Mountan Science,2007,25(1):93～98.
[6]薄景山,徐国栋,景立平.土边坡地震反应及其动力稳定性分析[J].地震工程与工程振动,2001,21(3):116～120.Bo Jingshan,Xu Guodong,Jing Liping.Seismic response and dy-namic stability analysis of soil slopes.Earthquake Engineering andEngineering Vibration,2001,21(3):116～120.
[7]金亮星,李建.高速铁路路堑岩质边坡的动力响应分析[J].振动工程学报,2008,21(4):354～358.Jin Liangxing,Li Jian.Dynamic response analysis of cutting rockslope under high speed train vibration load.Journal of VibrationEngineering,2008,21(4):354～358.
[8]周剑,张路青,王学良.水平层状岩体边坡动力响应中的结构面效应研究[J].工程地质学报,2011,19(3):352～358.Zhou Jian,Zhang Luqing,Wang Xueliang.Effect of structuralplane on dynamic response of rock slopes with horizontal strata.Journal of Engineering Geology,2011,19(3):352～358.
[9]言志信,曹小红,张刘平,张海东.地震作用下黄土边坡动力响应数值分析[J].岩土力学,2011,(增2):610～614.Yan Zhixin,Cao Xiaohong,Zhang Liuping,Zhang Haidong.Nu-merical analysis of loess slope dynamic response under earthquake.Rock and Soil Mechanics,2011,(s2):610～614.
[10]DEL Gaudio V,Wasowski J.Advances and problems in under-standing the seismic response of potentially unstable slopes.Eng.Geol.2010,doi:10.1016/j.enggeo.2010.09.007.
[11]George D.Bouckovalas,Achilleas G.Papadomotriou.Numericalevaluation of slope topography effects on seismic ground motion.Soil Dynamics and Earthquake Engineering,2005,25(7～10):547～558.
[12]YQ Liu,HB Li,J Zhao.UDEC simulation for the dynamic re-sponse of a rock slope subject to explosions.International Journalof Rock Mechanics&Mining Sciences,2004,41:474.
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