摘要
研究我国川滇甘陕地区Ⅱ类场地的长周期地震动反应谱特征参数以及主要因素对其的影响规律。通过对反应谱的分析,本文基于Newmark-Hall模型计算的加速度谱的拐点周期,分析两个拐点周期随震中距和震级的变化规律以及两者之间的相关性。最后应用差分进化算法拟合出长周期的衰减指数。其结果表明:2个拐点周期随着震中距和震级的增大而增大;震中距和震级对于2个拐点周期的相关性基本处于偏弱的水平,表明这两个拐点周期随着震级和震中距的变化而变化,从而不适合采用单一的震级和震中距来确定设计谱的拐点周期;特征周期T_(g)和第二下降段特征周期T_(D)的线性相关性较弱,现有的抗震规范中以特征周期来确定第二下降段特征周期的线性模型并不适合于长周期反应谱。根据该地区Ⅱ类场地的统计平均值,本文给出了2个拐点周期的建议值。最后由差分进化算法拟合平均谱给出长周期地震动反应谱的衰减指数的建议值,以供抗震规范修订时做参考。
The characteristic parameters of long-period ground motion response spectrum and the influence of main factors on the response spectrum are studied in class II sites in Sichuan,Yunnan,Gansu and Shaanxi regions.Through the analysis of the response spectrum,this article calculates the inflection point period of the acceleration spectrum based on the Newmark-Hall model.The law of the change of the two inflection points with the epicentral distance and magnitude and the correlation between them are analyzed.Finally,the differential evolution algorithm is used to fit the long period attenuation exponent.The results show that the two turning point periods increase with the increase of epicentral distance and magnitude.The correlation between the epicentral distance and magnitude for the two turning point periods is basical at a weak level.It shows that the two turning points vary with magnitude and epicentral distance.Therefore,it is not suitable to use single magnitude and epicentral distance to determine the turning point period of the design spectrum.The linear correlation between the characteristic period T_(g)and the second descending segment characteristic period T_(D)is weak.The linear model of characteristic period to determine the second descending segment characteristic period is not suitable for the long-period response spectra in the existing seismic code.According to the statistical average of class II sites in the area,this paper gives the recommended values of two turning point periods.Finally,the average spectrum is fitted by differential evolution algorithm,and the recommended value of attenuation index of long-period ground motion response spectrum is given.It can be used as a reference for the revision of seismic code.
作者
王振宇
赵培培
谢志南
薄景山
WANG Zhenyu;ZHAO Peipei;XIE Zhinan;BO Jingshan(Key Laboratory of Building Collapse Mechanism and Disaster Prevention,Institute of Disaster Prevention,China Earthquake Administration,Sanhe 065201;Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Disaster Mitigation,Ministry of Emergency Management,Harbin 150080,China)
出处
《自然灾害学报》
CSCD
北大核心
2022年第2期198-203,共6页
Journal of Natural Disasters
基金
中国地震局工程力学研究所基本科研业务费专项资助项目(2021EEEVL0102)
河北省自然科学基金项目(E2021512002)。
关键词
设计反应谱
长周期地震动
特征周期
衰减指数
design response spectrum
long-period ground motion
characteristic period
attenuation power index
