基于黑龙江经验场地模型的地震动放大效应研究  

Research on earthquake ground motion amplification effect based on the empirical site model in Heilongjiang province

作　　者：齐文浩[1,2] 陈方晓 李林芳 张苋凯 QI Wenhao;CHEN Fangxiao;LI Linfang;ZHANG Xiankai(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)

机构地区：[1]中国地震局工程力学研究所地震工程与工程振动重点实验室,黑龙江哈尔滨150080 [2]地震灾害防治应急管理部重点实验室,黑龙江哈尔滨150080

出　　处：《世界地震工程》2024年第4期142-150,共9页World Earthquake Engineering

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(2019C06);黑龙江省科学基金项目(LH2021E121)。

摘　　要：局部场地效应是抗震设计规范中的重要内容,以场地类别为基础的场地效应划分结果较为粗略。为解决这一问题,以黑龙江地区土层分布及其剪切波速、土动力特性和密度等资料为基础,统计出场地土参数随深度的变化特征,利用统计结果建立深度从10~80 m不等的15个经验场地模型。以黑龙江地区典型基岩加速度反应谱为目标谱,人工合成地震动作为输入,为了消除随机相位的影响,每一目标谱合成400条地震动加速度时程。分别计算这15个经验场地模型的地震反应,得到不同超越概率水准下地表峰值加速度统计值以及加速度反应谱标定谱的动力放大系数统计值。计算结果表明:随着场地厚度的增加,场地周期在逐渐增加,场地峰值地面加速度(peak ground acceleration,PGA)放大倍数呈现减小的趋势;随输入地震动强度的增加,场地PGA放大倍数减小的趋势呈现出非线性,动力放大系数随场地覆盖层变厚呈现先减小后增大的趋势;随着地震动强度的增加,动力放大系数逐渐减小且随土层厚度的变化趋势趋于平缓。动力放大系数结果不是定值2.5,场地较薄并且地震动较小的情况下,动力放大系数远超2.5;场地较厚并且地震动较强时,动力放大系数大多趋于2.5。Local site effect is an important content in the seismic design code,and the result of site effect classification based on site category is rather rough.To solve this problem,based on the data of soil layer distribution and shear wave velocity,soil dynamic characteristics and density in Heilongjiang area,the statistical characteristics of the variation of site parameters with depth were statistically analyzed and 15 empirical site models with depth ranging from 10 to 80 m were established.Taking the typical acceleration response spectrum of bedrock in Heilongjiang as the target spectrum,in order to eliminate the effect of random phase,400 seismic acceleration time histories for each target spectrum were synthesized as inputs.The seismic responses of the 15 model sites were calculated,the statistic value of the peak acceleration and the statistic value of the dynamic amplification coefficient of the calibration spectrum of the acceleration response are obtained.The results show that the period of the site increases gradually with the thickness of the soil layer,whereas the amplification of the PGA(peak ground acceleration)of the site decreases;With the increase of the input seismic intensity,the amplification of the site PGA is nonlinear;The dynamic amplification coefficient shows a tendency of decreasing first and then increasing with the thickness of the soil layer;With the increase of seismic intensity,the dynamic amplification coefficient decreases gradually and the trend of soil layer thickness tends to be smooth;The result of dynamic amplification coefficient is not a fixed value of 2.5,and the dynamic amplification coefficient far exceeds 2.5 when the soil layer is not thick and the seismic ground motion is low.When the soil layer is thicker and the seismic ground motion is stronger,the dynamic amplification coefficient mostly tends to be 2.5.

关 键 词：场地放大倍数 动力放大系数 场地基本周期 地表峰值加速度 设计反应谱 反应谱标定 

分 类 号：TU42[建筑科学—岩土工程]