土层模型参数变异性对场地地表地震动的影响分析  

Analysis of Influence of Soil Model Parameter Variability on Ground Motion Response

作　　者：冯伟栋[1] 曹均锋[1] 彭刘亚[1] 王德才[2] FENG Weidong;CAO Junfeng;PENG Liuya;WANG Decai(Anhui Earthquake Agency, Hefei 230031, China;School of Architecture and Art, Hefei University of Technology, Hefei 230009, China)

机构地区：[1]安徽省地震局,安徽合肥230031 [2]合肥工业大学建筑与艺术学院,安徽合肥230009

出　　处：《防灾科技学院学报》2020年第3期28-34,共7页Journal of Institute of Disaster Prevention

摘　　要：土层地震反应分析是获取场地地表设计地震动的重要途径,但是土层模型参数的变异性会对场地地表地震动产生较大影响。选取华东地区某实际场地土层模型为研究对象,以不同频谱成分不同幅值的天然地震动记录作为模型输入条件,采用频域等效线性化法分析了土层的剪切波速、输入界面位置及输入界面波速、分层厚度等土层模型参数变异性对场地地表地震动的影响。结果表明土层模型参数变异性对场地地表地震动变异性有重要影响,具体表现为:地表峰值加速度与土层剪切波速呈正相关,地表地震动加速度反应谱特征周期与土层剪切波速呈负相关;地表峰值加速度随输入界面埋深和输入界面处剪切波速的增加而增加,但输入界面埋深变化及剪切波速的变化对地表加速度反应谱特征周期影响有限;分层厚度较大的土层模型计算得到的场地地表地震动峰值和反应谱特征周期值均偏低,这将使获取的设计地震动偏于不安全,因此构建土层模型时应尽可能将各土层进行细分。Soil seismic response analysis is an important way to obtain the design ground motion of site surface,but the variability of parameters of the soil model will have a great impact on the ground motion of site surface.Basing on the data of soil layer model of an actual typical site in East China and taking ground motion records with different spectral components and different amplitudes as the model input conditions,we analyzed the influence of soil layer model parameters,such as soil shear velocity,position and wave speed of the input interface,and layer thickness and calculating soil thickness on the ground motion response of the site by the one-dimensional equivalent linear method in the frequency domain.As the results show,the variability of the soil model parameters has great influence on the variability of the ground motion,which was mainly presented as follow:with the increase of shear velocity,the peak ground acceleration(Amax)on the surface of the site increases while the characteristic period of the acceleration response spectra(Tg)decreases.Amax on the surface of the site increases with the increase of the buried depth of input interface and the shear velocity,whose change,however,has only a limited effect on Tg.The peak value of ground motion and characteristic period of response spectrum calculated through the soil layer model with larger layer thickness are generally low,which will make the obtained design ground motion unsafe.Therefore,the soil layer thickness should be less than 2 m for safety design reason when constructing the soil layer mode.

关 键 词：输入界面 剪切波速 分层厚度 峰值加速度 特征周期 

分 类 号：P315.9[天文地球—地震学]