SV垂直入射时LowerHutt沉积盆地竖向地震动分析  

Vertical ground motion analysis of LowerHutt sedimentary basin of SV vertical incidence

作　　者：游昊冉 杨笑梅[1] YOU Haoran;YANG Xiaomei(Faculty of Civil and Transportation Engineering,Guangdong University of Technology,Guangzhou 510006,China)

机构地区：[1]广东工业大学土木与交通工程学院

出　　处：《地震工程与工程振动》2019年第5期199-207,共9页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51639006,51178123);国家重点研发计划(2018YFC1504004)~~

摘　　要：本文选取新西兰LowerHutt峡谷盆地为研究对象,主要研究该盆地在SV地震波垂直入射时地表竖向地震反应特征,及其沉积土层非线性特征对地表竖向地震反应的影响。本研究依据已有的场地地质勘查地质构造资料,建立Abaqus二维显式有限元分析模型,设置黏性人工边界,特别是通过二次开发引入二维黏弹塑性本构模型成功实现了二维土体非线性特征分析。研究结果显示,在沉积土层越深的地方,非线性特征越明显,频谱放大作用会向低频转移。在盆地边缘处有明显的边缘放大特征,尤其是盆地右边缘的竖向分量强度远超水平分量,超过抗震规范里竖向地震动取水平地震动65%的设计要求,揭示了盆地震害异常严重的原因之一。This paper aims at analysis of vertical seismic response characteristics in an alluvial basin in the city of Lower Hutt in New Zealand.The influence of the nonlinear characteristics of the sedimentary soil layers is mainly considered on the vertical ground motion.Based on the existing geological exploration geological structure data,this paper establishes a two-dimensional explicit finite element analysis model in Abaqus software,and applies a viscous artificial boundary on the FEM model.A two-dimensional viscoelastic constitutive model is developed through user subroutine.Based on the 2D soil nonlinear model,the estimation of seismic response is realized.The results show the deeper the sedimentary soil layer,the more obvious effect on the nonlinear characteristics.The spectral amplification shifts to the low frequency.The obvious amplification of seismic ground motion is observed at the edge of the basin.The vertical component intensity at the right edge of the basin is far beyond the horizontal component,exceeding the design requirements of 65%of the seismic code.This amplification of vertical ground motion reveals one of the reasons of the serious earthquake damage.

关 键 词：竖向地震动 地震反应特征 沉积盆地 非线性 边缘效应 

分 类 号：P315.8[天文地球—地震学] P315.9[天文地球—固体地球物理学]