多维地震动输入下沉积盆地地震效应对比研究  

Comparative study on seismic effects of sedimentary basins under multi-dimensional ground motion inputs

作　　者：熊甜慧 于彦彦[1] 丁海平[1] XIONG Tianhui;YU Yanyan;DING Haiping(Key Laboratory of Structure Engineering of Jiangsu Province,Suzhou University of Science and Technology,Suzhou 215011,China)

机构地区：[1]苏州科技大学江苏省结构工程重点实验室,江苏苏州215011

出　　处：《地震工程与工程振动》2025年第2期136-144,共9页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金青年基金项目(51808371);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(2021EEEVL0001)。

摘　　要：对于盆地等局部不均匀场地在平面波入射下的地震反应分析多假定地震动为单一波型(SV波、SH波或P波)输入,而实际入射的地震动一般为多向耦合的震动。文中基于谱元法模拟了三维半椭球形沉积盆地在平面波垂直入射下的地震动响应,通过分析地表加速度峰值、放大系数分布、地表点剖面时程以及特征频率处的反应谱比分布,对比研究了多维地震动输入下沉积盆地的地震动放大特征。结果表明:输入双向水平地震激励相比输入单向水平地震激励对盆地内地震动有明显放大作用,最大放大系数可达1.87。考虑双向水平地震动同时输入的影响后,会显著改变地表加速度峰值的分布特征,双向输入时沿各向传播的波的叠加干涉使得加速度峰值呈不对称分布。双向地震动作用使得波传播特征变得更加复杂,最强烈地震动的位置发生改变。双向输入除对反应谱值有放大外,对其卓越周期的分布也会产生一定影响。In the seismic response analysis of locally irregular sites such as basins under plane wave incidence,it is usually assumed that the input seismic motion is of a single wave type,i.e.,SV wave,SH wave,or P wave.However,the actual incident motion is generally a multi-dimensional coupled shaking case.Based on the spectral element method,the ground motion response of a three-dimensional semi-ellipsoidal sedimentary basin under the vertical incidence of plane waves is simulated.By analyzing the distributions of peak ground acceleration(PGA)and the corresponding amplification factor,the seismograms along the surface point profile,and the response spectrum ratio distribution at the characteristic frequencies,the ground motion amplification features of the sedimentary basin under multi-dimensional ground motion input are investigated through comparisons with the results of single wave type incidence.The results show that compared with the unidirectional horizontal seismic excitation,the bidirectional horizontal seismic input has a significant amplification effect on ground motion in the basin,and the maximum amplification factor can reach 1.87.Considering the influence of simultaneous input of bidirectional horizontal ground motion,the distribution characteristics of the peak ground acceleration will change significantly.The superposition and interference of waves propagating in different directions result in an asymmetrical PGA distributions.The bidirectional ground motion input makes the wave propagation characteristics more complex,and the location of the strongest ground shaking changes.In addition to the amplification of the response spectrum value,the bidirectional input also has a certain influence on the distribution of the predominant period.

关 键 词：谱元法 三维沉积盆地 平面波 双向地震动输入 放大系数 

分 类 号：P315.9[天文地球—地震学]