【作者】 孙强强； 薄景山； 郭晓云； 景立平；

【Author】 Sun Qiangqiang;Bo Jingshan;Guo Xiaoyun;Jing Liping;Institute of Disaster Prevention;Institute of Engineering Mechanics,China Earthquake Administration;

【机构】 防灾科技学院； 中国地震局工程力学研究所；

【摘要】 采用有限差分方法构建一组数值计算模型进行了土层地震反应分析,研究了不同土体阻尼形式对地表加速度反应谱和谱参数的影响。结果表明:阻尼形式对加速度反应谱高频段影响显著,对低频段影响有限;而随着土体卓越频率的减小,影响范围向长周期方向发展,反应谱的相对误差也逐渐增大;当土体卓越频率远低于输入地震动峰值频率时,加速度反应谱谱值最大相对偏差可达9倍;阻尼形式对反应谱特征周期、衰减指数影响较小,而对平台值影响较大;只考虑土体卓越频率的阻尼形式会低估土层的地震反应。更多还原

【Abstract】 A series of numerical models were developed to simulate the site response and to investigate the effect of damping models on response spectra in time—domain based on Finite difference methodC FDM).A full Rayleigh damping was adopted and the low frequency was selected as the fundamental site frequency,the high frequency(optimal frequency) was determined by five methods.Analyzes revealed that damping models have significant impact on the high frequency band of the acceleration response spectra,but influence limited on the low frequency.With the decrease of the fundamental site frequency,the influence ranged to the long period and the relative error of response spectra was gradually increasing.When the fundamental site frequency was much lower than the predominant frequency of input motions,the maximum relative deviation of the acceleration response spectra was up to 9 times in different damping models.The damping models had little influence on the characteristic period of response spectra and attenuation index,but had great influence on the platform value.The seismic response of the site could be underestimated only by considering the fundamental site frequency.更多还原