汶川地震远场黄土场地地震动场地放大效应机制研究
|
摘要
通过汶川地震震后科学考察发现,汶川地震局部场地的震害和地震动放大效应明显,地震对甘肃省境内远离震中的黄土地区造成了较为严重的破坏。在此基础上,结合钻孔波速测试,运用二维等价线性时程响应动分析法对甘肃省平凉市典型黄土塬进行了地震动力响应计算,分析了该地区局部场地条件对地震动放大效应的影响。研究发现,黄土塬具有地震动放大效应,随着塬高的增加,加速度、速度、位移均出现放大效应;随着地震动在黄土覆盖层中的传递,卓越频率向低频移动,高频成分被吸收,加速度反应谱中长周期分量逐渐增大。数值计算结果与实际震害基本吻合,其结果对黄土地区进行合理的抗震设防具有一定的科学意义。
Based on earthquake damage investigation after the Wenchuan Ms8.0 earthquake,it is discovered that the phenomena of site amplification effects on ground motion were very obvious both in the mountainous area of southeastern Gansu province and the Loess Plateau areas.Combining with the borehole exploration,site seismic response analysis of the typical loess tableland at Pingliang City,Gansu province is carried out applying the dynamic finite element method of two dimensions linearly equivalent for dynamic response numerical calculation;the local amplification effect of the loess tableland is studied as well.The results show that there are seismic amplification effects at loess tableland;and acceleration,velocity and displacement increases with increase in tableland height gradually.Moreover,the low frequency components become more abundant and the high-frequency components are absorbed with increase in tableland height.The long-period components of acceleration response spectrum have increased gradually as well.The numerical results are basically consistent with the earthquake damages,so as to have certain scientific significance for the reasonable seismic fortification in loess regions.
Based on earthquake damage investigation after the Wenchuan Ms8.0 earthquake,it is discovered that the phenomena of site amplification effects on ground motion were very obvious both in the mountainous area of southeastern Gansu province and the Loess Plateau areas.Combining with the borehole exploration,site seismic response analysis of the typical loess tableland at Pingliang City,Gansu province is carried out applying the dynamic finite element method of two dimensions linearly equivalent for dynamic response numerical calculation;the local amplification effect of the loess tableland is studied as well.The results show that there are seismic amplification effects at loess tableland;and acceleration,velocity and displacement increases with increase in tableland height gradually.Moreover,the low frequency components become more abundant and the high-frequency components are absorbed with increase in tableland height.The long-period components of acceleration response spectrum have increased gradually as well.The numerical results are basically consistent with the earthquake damages,so as to have certain scientific significance for the reasonable seismic fortification in loess regions.
引文
[1]LIU DONGSHENG,Loess and the environment[M].Beijing:China Ocean Press,1985.
[2]张振中.黄土地震灾害预测[M].北京:地震出版社,1999.
[3]吴志坚,车爱兰,王兰民,等.常时微动测试在汶川地震甘肃灾区建筑结构震害调查中的应用[J].西北地震学报,2009,31(1):86-90.WU Zhi-jian,CHE Ai-lan,WANG Lan-ming,et al.Application of micro tremor observation on disasterinvestigation of the 2008 Wenchuan earthquake forbuilding structures in the quake hit areas of Gansuprovince[J].Northwest Seismology Journal,2009,31(1):86-90.
[4]王兰民,吴志坚.汶川地震场地条件对地震动放大效应的影响[J].土木建设与环境工程,2010,32(增刊2):175-178.WANG Lan-min,WU Zhi-jian.Influence of site conditionon seismic amplification effects during the Wenchuanearthquake[J].Journal of Civil,Architectural&Environmental Engineering,2010,32(Supp.2):175-178.
[5]姚文波,刘文兆,侯甬坚,等.汶川大地震陇东黄土高原崩塌滑坡的调查分析[J].生态学报,2008,28(12):5917-5926.YAO Wen-bo,LIU Wen-zhao,HOU Yong-jian,et al.Investigation and analysis of collapses and landslides onthe Loess Plateau of East Gansu Province after the 5.12Wenchuan Earthquake[J].Acta Ecologica Sinica,2008,28(12):5917-5926.
[6]石玉成,卢育霞.汶川8.0级地震甘肃灾区震害特点及恢复重建对策[J].西北地震学报,2009,1(1):1-7.SHI Yu-cheng,LU Yu-xia.the damage features ofWenchuan 8.0 earthquake in Gansu disaster area andcountermeasures of reconstruction[J].NorthwesternSeismological Journal,2009,31(1):1-7.
[7]言志信,曹小红,张刘平,等.地震作用下黄土边坡动力响应数值分析[J].岩土力学,2011,32(增刊2):610-614.YAN Zhi-xin,CAO Xiao-hong,ZHANG Liu-ping,et al.Numerical analysis of loess slope dynamic responseunder earthquake[J].Rock and Soil Mechanics,2011,32(Supp.2):610-614.
[8]车爱兰,岩楯敞广,葛修润.关于地铁地震响应的模型振动实验及数值分析[J].岩土力学,2006,27(8):1293-1298.CHE Ai-lan,IWATATE TAKAHIRO,GE Xiu-run.Dynamic behaviors of subway structure subjected tostrong earthquake motions using shaking table tests anddynamic analyses[J].Rock and Soil Mechanics,2006,27(8):1293-1298.
[2]张振中.黄土地震灾害预测[M].北京:地震出版社,1999.
[3]吴志坚,车爱兰,王兰民,等.常时微动测试在汶川地震甘肃灾区建筑结构震害调查中的应用[J].西北地震学报,2009,31(1):86-90.WU Zhi-jian,CHE Ai-lan,WANG Lan-ming,et al.Application of micro tremor observation on disasterinvestigation of the 2008 Wenchuan earthquake forbuilding structures in the quake hit areas of Gansuprovince[J].Northwest Seismology Journal,2009,31(1):86-90.
[4]王兰民,吴志坚.汶川地震场地条件对地震动放大效应的影响[J].土木建设与环境工程,2010,32(增刊2):175-178.WANG Lan-min,WU Zhi-jian.Influence of site conditionon seismic amplification effects during the Wenchuanearthquake[J].Journal of Civil,Architectural&Environmental Engineering,2010,32(Supp.2):175-178.
[5]姚文波,刘文兆,侯甬坚,等.汶川大地震陇东黄土高原崩塌滑坡的调查分析[J].生态学报,2008,28(12):5917-5926.YAO Wen-bo,LIU Wen-zhao,HOU Yong-jian,et al.Investigation and analysis of collapses and landslides onthe Loess Plateau of East Gansu Province after the 5.12Wenchuan Earthquake[J].Acta Ecologica Sinica,2008,28(12):5917-5926.
[6]石玉成,卢育霞.汶川8.0级地震甘肃灾区震害特点及恢复重建对策[J].西北地震学报,2009,1(1):1-7.SHI Yu-cheng,LU Yu-xia.the damage features ofWenchuan 8.0 earthquake in Gansu disaster area andcountermeasures of reconstruction[J].NorthwesternSeismological Journal,2009,31(1):1-7.
[7]言志信,曹小红,张刘平,等.地震作用下黄土边坡动力响应数值分析[J].岩土力学,2011,32(增刊2):610-614.YAN Zhi-xin,CAO Xiao-hong,ZHANG Liu-ping,et al.Numerical analysis of loess slope dynamic responseunder earthquake[J].Rock and Soil Mechanics,2011,32(Supp.2):610-614.
[8]车爱兰,岩楯敞广,葛修润.关于地铁地震响应的模型振动实验及数值分析[J].岩土力学,2006,27(8):1293-1298.CHE Ai-lan,IWATATE TAKAHIRO,GE Xiu-run.Dynamic behaviors of subway structure subjected tostrong earthquake motions using shaking table tests anddynamic analyses[J].Rock and Soil Mechanics,2006,27(8):1293-1298.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心