瑞利面波地形效应的数值模拟研究
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摘要
在地震工程中,经常观测到地震波受地表起伏的影响而产生地形效应.本文基于数值模拟,研究了地震远场区域起伏地形对地表瑞利面波传播影响和对应的地形效应特征.结果表明:起伏地形的转折点或面的散射或反射,产生反方向传播的反射RR波和向空间扩散传播的转换RS体波,导致通过地形的瑞利面波能量极大的减弱,地形总体表现出强的隔震效应.地形起伏与地震动的波长比越大,隔震效应越强.凹陷地形表现出远比隆起地形更大的隔震效应.起伏地形转折引起的地表张角变化,导致地震动能量分布密度改变,是地形出现局部放大或减弱特征的主要因素.地表张角小于180°,地震动放大,张角越小放大作用越明显.地表张角大于180°,地震动减弱,张角越大减弱作用越强.当地形对地震动产生放大作用时,地震动水平分量比垂直分量放大效果更明显,而当地形产生减弱作用时,相对于水平分量,垂直分量更容易被减弱.
In earthquake engineering,topographical effects on the ground motion caused by rugged terrain have been frequently observed. In the present paper, based on the numerical simulation, the effects of Rayleigh surface wave propagating along the rugged terrain are studied which are dominant in the far-field area. The results first show that due to the reflected RR and converted RS waves caused by the reflection,or diffraction of topographic turning point or surface, can greatly reduce the energy of propagating Rayleigh surface waves, all the topography show strong vibration isolation effects. With the increasing of the ratio of wavelength to topography scale, the vibration isolation effect increasing. The depression terrains show much strong vibration isolation effects than that bump terrains do. On the other hand, the energy density change caused by the varying surface angles of rolling topography turning point is the main factor for local vibration amplify, or reduce of the topography. When the angle is less than 180° the vibration amplitude increases with the angle deceasing.When the angle is large than 180°,the vibration amplitude decreases with the angle increasing.Moreover,for the topography amplify effects of the horizontal component is much higher than that of the vertical component, while the topography reduce effects of the vertical component is much stronger than that of the horizontal component.
In earthquake engineering,topographical effects on the ground motion caused by rugged terrain have been frequently observed. In the present paper, based on the numerical simulation, the effects of Rayleigh surface wave propagating along the rugged terrain are studied which are dominant in the far-field area. The results first show that due to the reflected RR and converted RS waves caused by the reflection,or diffraction of topographic turning point or surface, can greatly reduce the energy of propagating Rayleigh surface waves, all the topography show strong vibration isolation effects. With the increasing of the ratio of wavelength to topography scale, the vibration isolation effect increasing. The depression terrains show much strong vibration isolation effects than that bump terrains do. On the other hand, the energy density change caused by the varying surface angles of rolling topography turning point is the main factor for local vibration amplify, or reduce of the topography. When the angle is less than 180° the vibration amplitude increases with the angle deceasing.When the angle is large than 180°,the vibration amplitude decreases with the angle increasing.Moreover,for the topography amplify effects of the horizontal component is much higher than that of the vertical component, while the topography reduce effects of the vertical component is much stronger than that of the horizontal component.
引文
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?elebi M.1987.Topographical and geological amplifications determined from strong-motion and aftershock records of the 3 March 1985 Chile earthquake[J].Bulletin of the Seismological Society of America,77(4):1147-1167.
Costantino C J,Miller C A,Lufrano L A.1976.Soil-structure interaction parameters from finite element analysis[J].Nuclear Engineering and Design,38(2):289-302,doi:10.1016/0029-5493(76)90103-5.
Davis L L,West L R.1973.Observed effects of topography on ground motion[J].Bulletin of the Seismological Society of America,63(1):283-298.
Han C,Liu Z P,Zhang R H,et al.2017.Numerical simulation of the Rayleigh surface wave two-dimensional physical models[J].Progress in Geophysics (in Chinese),32(1):357-362,doi:10.6038/pg20170151.
Hartzell S H,Carver D L,King K W.1994.Initial investigation of site and topographic effects at robinwood ridge,California[J].Bulletin of the Seismological Society of America,84(5):1336-1349.
Kausel E,Tassoulas J L.1981.Transmitting boundaries:a closed-form comparison[J].Bulletin of the Seismological Society of America,71(1):143-159.
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Wang W.2011.Effect of hill topography on ground motion[Ph.D.thesis].Harbin:Institute of Engineering Mechanics,China Earthquake Administration.
Yu S P.1996.Wide-band Ricker wavelet[J].Oil Geophysical Prospecting (in Chinese),31(05):605- 615.
Yu W F,Liu Z P.2015.A numerical study of the Rayleigh wave particle motions excited by a point source and Poisson’s ratio for lateral inhomogeneous half-spaces[J].Journal of Applied Geophysics,123:242-255,doi:10.1016/j.jappgeo.2015.09.009.
Zhou H,Chen X F.2006.A study on frequency responses of topography with different scales due to incident SH wave[J].Chinese Journal Of Geophysics (in Chinese),49(01):205-211,doi:10.3321/j.issn:0001-5733.2006.01.027.
Zhou H,Chen X F.2007.A study on the effect of depressed topography on Rayleigh surface wave[J].Chinese Journal Of Geophysics (in Chinese),50(04):1182-1189,doi:10.3321/j.issn:0001-5733.2007.04.027.
Zhou H,Gao M T,Yu Y X.2010.A study of topographical effect on SH waves[J].Progress In Geophysics (in Chinese),25(3):775-782,doi:10.3969/j.issn.1004-2903.2010.03.005.
Zhou X T,Han J L,Shi F G,et al.2014.Numerical simulation for amplification effect of topography and geomorphology to seismic waves[J].Journal of Engineering Geology (in Chinese),22(06):1211-1220,doi:10.13544/j.cnki.jeg.2014.06.027.
Zhou Z H,Zhang Y M,Sun P S,et al.2003.Study on effect of fault on seismic damage[J].Journal of Natural Disasters (in Chinese),12(04):20-24.
Zong F K.1984.Dispersion characteristics and discretization criterion of finite element analysis in wave propagation problem[J].Explosion and Shock Waves (in Chinese),4(04):16-23.
韩超,刘争平,张瑞华,等.2017.瑞利面波二维物理模型的数值模拟研究[J].地球物理学进展,32(01):357-362,doi:10.6038/pg20170151.
李渝生,黄润秋.2009.5.12汶川大地震损毁城镇的震害效应与重建选址问题[J].岩石力学与工程学报,28(07):1370-1376.
王伟.2011.地震动的山体地形效应研究[博士论文].哈尔滨:中国地震局工程力学研究所.
俞寿朋.1996.宽带Ricker子波[J].石油地球物理勘探,31(05):605- 615.
周红,陈晓非.2006.不同尺度地形的SH波频率域响应特征研究[J].地球物理学报,49(01):205-211,doi:10.3321/j.issn:0001-5733.2006.01.027.
周红,陈晓非.2007.凹陷地形对Rayleigh面波传播影响的研究[J].地球物理学报,50(04):1182-1189,doi:10.3321/j.issn:0001-5733.2007.04.027.
周红,高孟潭,俞言祥.2010.SH波地形效应特征的研究[J].地球物理学进展,25(3):775-782,doi:10.3969/j.issn.1004-2903.2010.03.005.
周兴涛,韩金良,施凤根,等.2014.地形地貌对地震波放大效应数值模拟研究[J].工程地质学报,22(06):1211-1220,doi:10.13544/j.cnki.jeg.2014.06.027.
周正华,张艳梅,孙平善,等.2003.断层对震害影响的研究[J].自然灾害学报,12(04):20-24.
宗福开.1984.波传播问题中有限元分析的频散特性及离散化准则[J].爆炸与冲击,4(04):16-23.
?elebi M.1987.Topographical and geological amplifications determined from strong-motion and aftershock records of the 3 March 1985 Chile earthquake[J].Bulletin of the Seismological Society of America,77(4):1147-1167.
Costantino C J,Miller C A,Lufrano L A.1976.Soil-structure interaction parameters from finite element analysis[J].Nuclear Engineering and Design,38(2):289-302,doi:10.1016/0029-5493(76)90103-5.
Davis L L,West L R.1973.Observed effects of topography on ground motion[J].Bulletin of the Seismological Society of America,63(1):283-298.
Han C,Liu Z P,Zhang R H,et al.2017.Numerical simulation of the Rayleigh surface wave two-dimensional physical models[J].Progress in Geophysics (in Chinese),32(1):357-362,doi:10.6038/pg20170151.
Hartzell S H,Carver D L,King K W.1994.Initial investigation of site and topographic effects at robinwood ridge,California[J].Bulletin of the Seismological Society of America,84(5):1336-1349.
Kausel E,Tassoulas J L.1981.Transmitting boundaries:a closed-form comparison[J].Bulletin of the Seismological Society of America,71(1):143-159.
LI Y S,Huang R Q.2009.Earthquake Damage Effects Of Towns And Reconstruction Site Selection In Wenchuan Earthquake On May 12,2008[J].Chinese Journal of Rock Mechanics and Engineering (in Chinese),28(07):1370-1376.
Wang W.2011.Effect of hill topography on ground motion[Ph.D.thesis].Harbin:Institute of Engineering Mechanics,China Earthquake Administration.
Yu S P.1996.Wide-band Ricker wavelet[J].Oil Geophysical Prospecting (in Chinese),31(05):605- 615.
Yu W F,Liu Z P.2015.A numerical study of the Rayleigh wave particle motions excited by a point source and Poisson’s ratio for lateral inhomogeneous half-spaces[J].Journal of Applied Geophysics,123:242-255,doi:10.1016/j.jappgeo.2015.09.009.
Zhou H,Chen X F.2006.A study on frequency responses of topography with different scales due to incident SH wave[J].Chinese Journal Of Geophysics (in Chinese),49(01):205-211,doi:10.3321/j.issn:0001-5733.2006.01.027.
Zhou H,Chen X F.2007.A study on the effect of depressed topography on Rayleigh surface wave[J].Chinese Journal Of Geophysics (in Chinese),50(04):1182-1189,doi:10.3321/j.issn:0001-5733.2007.04.027.
Zhou H,Gao M T,Yu Y X.2010.A study of topographical effect on SH waves[J].Progress In Geophysics (in Chinese),25(3):775-782,doi:10.3969/j.issn.1004-2903.2010.03.005.
Zhou X T,Han J L,Shi F G,et al.2014.Numerical simulation for amplification effect of topography and geomorphology to seismic waves[J].Journal of Engineering Geology (in Chinese),22(06):1211-1220,doi:10.13544/j.cnki.jeg.2014.06.027.
Zhou Z H,Zhang Y M,Sun P S,et al.2003.Study on effect of fault on seismic damage[J].Journal of Natural Disasters (in Chinese),12(04):20-24.
Zong F K.1984.Dispersion characteristics and discretization criterion of finite element analysis in wave propagation problem[J].Explosion and Shock Waves (in Chinese),4(04):16-23.
韩超,刘争平,张瑞华,等.2017.瑞利面波二维物理模型的数值模拟研究[J].地球物理学进展,32(01):357-362,doi:10.6038/pg20170151.
李渝生,黄润秋.2009.5.12汶川大地震损毁城镇的震害效应与重建选址问题[J].岩石力学与工程学报,28(07):1370-1376.
王伟.2011.地震动的山体地形效应研究[博士论文].哈尔滨:中国地震局工程力学研究所.
俞寿朋.1996.宽带Ricker子波[J].石油地球物理勘探,31(05):605- 615.
周红,陈晓非.2006.不同尺度地形的SH波频率域响应特征研究[J].地球物理学报,49(01):205-211,doi:10.3321/j.issn:0001-5733.2006.01.027.
周红,陈晓非.2007.凹陷地形对Rayleigh面波传播影响的研究[J].地球物理学报,50(04):1182-1189,doi:10.3321/j.issn:0001-5733.2007.04.027.
周红,高孟潭,俞言祥.2010.SH波地形效应特征的研究[J].地球物理学进展,25(3):775-782,doi:10.3969/j.issn.1004-2903.2010.03.005.
周兴涛,韩金良,施凤根,等.2014.地形地貌对地震波放大效应数值模拟研究[J].工程地质学报,22(06):1211-1220,doi:10.13544/j.cnki.jeg.2014.06.027.
周正华,张艳梅,孙平善,等.2003.断层对震害影响的研究[J].自然灾害学报,12(04):20-24.
宗福开.1984.波传播问题中有限元分析的频散特性及离散化准则[J].爆炸与冲击,4(04):16-23.