软弱土层对场地地震动峰值的影响
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摘要
以江淮地区某软土场地为原型,构造多种场地土层地震反应分析模型,选择Taft(1952N21E)、Kobe(1995EW)和E1-Centro(1940NS)3条强震记录作为地震动输入,采用一维频域等效线性化波动方法重点分析了软弱层的埋深、厚度对软土场地地表加速度峰值的影响。结果表明:对于给定的输入地震动,地表加速度峰值及土层放大系数随着软弱层埋深、厚度的增加而逐渐减小;当软弱层的埋深、厚度超过一定值时,软土场地开始出现减震效应,软弱层的埋深越深、厚度越大、输入地震动强度越高,减震的效果越明显。
Basing on a soft site in Jianghuai region,we constructed several analyze models of site soil seismic response. Then we selected three earthquake records of Taft (1952N21E) ,Kobe ( 1995EW ) and E1-Centro ( 1940NS ) as the input waves,and analyzed the effect of the buried depth and the thickness of soft soil layer on ground peak acceleration in frequency domain through one-dimension equivalent linear fluctuation method. The results showed that for the given input ground motion,the ground acceleration peak and soil amplification factors decreased gradually with the increase of thickness or buried depth of soft site. When the thickness or buried depth of soft site exceeded a certain value,the soft site began to show vibration reduction effect,the deeper and the thicker of the soft layer,the higher intensity of input ground motion,the vibration reduction effect is more obvious.
Basing on a soft site in Jianghuai region,we constructed several analyze models of site soil seismic response. Then we selected three earthquake records of Taft (1952N21E) ,Kobe ( 1995EW ) and E1-Centro ( 1940NS ) as the input waves,and analyzed the effect of the buried depth and the thickness of soft soil layer on ground peak acceleration in frequency domain through one-dimension equivalent linear fluctuation method. The results showed that for the given input ground motion,the ground acceleration peak and soil amplification factors decreased gradually with the increase of thickness or buried depth of soft site. When the thickness or buried depth of soft site exceeded a certain value,the soft site began to show vibration reduction effect,the deeper and the thicker of the soft layer,the higher intensity of input ground motion,the vibration reduction effect is more obvious.
引文
薄景山,李秀领,李山有.2003.场地条件对地震动影响研究的若干进展[J].世界地震工程,19(2):11-15.
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齐文浩,薄景山.2007.土层地震反应等效线性化方法综述[J].世界地震工程,23(4):221-226.
袁丽侠.2003.场地土对地震波的放大效应[J].世界地震工程,19(1):113-120.
袁晓铭,孙锐,孙静,等.2000.常规土类动剪切模量和阻尼比试验研究[J].地震工程与工程振动,20(4):133-138.
董娣,周锡元,闫维明,等.2006.地震动不确定性及其影响因素的初步分析[J].地震研究,29(2):167-175.
黄雨,叶为民,唐益群,等.2005.上海软土场地的地震反应特征分析[J].地下空间与工程学报,1(5):773-778.
黄玉龙,郭迅,袁一凡,等.2000.软泥夹层对香港软土场地地震反应的影响[J].自然灾害学报,9(1):109-116.
李小军,彭青,刘文忠.2001.设计地震动参数确定中的场地影响考虑[J].世界地震工程,17(4):34-41.
刘峥,沈建文,石树中,等.2009.软土对基岩峰值加速度的放大作用[J].同济大学学报(自然科学版),37(5):607-611.
吕悦军,唐荣余,彭艳菊.2004.烟台海岸软土场地特征及对地震动参数的影响[J].中国地震,20(4):323-329.
齐文浩,薄景山.2007.土层地震反应等效线性化方法综述[J].世界地震工程,23(4):221-226.
袁丽侠.2003.场地土对地震波的放大效应[J].世界地震工程,19(1):113-120.
袁晓铭,孙锐,孙静,等.2000.常规土类动剪切模量和阻尼比试验研究[J].地震工程与工程振动,20(4):133-138.
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