摘要
局部场地条件对地震动特性影响显著,深厚的软弱覆盖层引起的地震动场地效应会显著放大中长周期反应谱。采用谱比法,对2020年7月12日唐山古冶5.1级地震中获得的部分强震动记录进行统计,发现在本次地震中北京城区的地震动场地效应显著,深厚覆盖层明显放大了加速度反应谱,在T=1.2 s左右反应谱放大倍数可达4.0,说明北京地区的场地和盆地效应使得远场地震动的中长周期成分显著放大。此外,发现参考基岩场地记录是否与土层场地处遭受的基岩地震动一致,仍然是制约统计结果可靠性的关键因素。
Ground motion characteristics are significantly affected by local site conditions,as spectral acceleraiongs at medium-to-long periods would be obviously amplified on thick and soft sites as a result of seismic site effects.The statistical results of strong-motion records obtained in M5.1 Guye,Tangshan earthquake on 12^th July,2020 by spectral ratio method indicated that,the seismic site effects in Beijing urban area were remarkable as the spectral acceleraiongs were evidently amplified by thick and soft soil layers,and the amplification factor could reach 4.0 at period T=1.2 s in this earthquake.In addition,the consistency between the ground motions which the soft soil sites suffered and the ground motions on reference bedrock sites was found to be the critical factor which restricted the reliability of statistical results by spectral ratio method.
作者
王玉石
李小军
刘艳琼
荣棉水
丁毅
Wang Yushi;Li Xiaojun;Liu Yanqiong;Rong Mianshui;Ding Yi(Faculty of Urban Construction,Beijing University of Technology,Beijing 100124,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;China Earthquake Risk and Insurance Laboratory,Beijing 100081,China;China Earthquake Networks Center,Beijing 100045,China)
出处
《地震科学进展》
2020年第7期14-19,共6页
Progress in Earthquake Sciences
基金
国家重点研发计划课题(2018YFC1504601)
国家自然科学基金项目(U1839202、51639006)
中国地震局地球物理研究所基本科研业务费专项(DQJB17T01)联合资助。
关键词
地震动
场地效应
加速度反应谱
标准谱比法
加速度记录
ground motion
seismic site effect
spectral acceleration
standard spectral ratio method
strong-motion record
