近断层竖向地震动P-Δ效应研究  

The Study about P-Δ Effect of Vertical Ground Motion in Near-fault

作　　者：范优铭[1] 夏群[2] 

机构地区：[1]常州工程职业技术学院,江苏常州213164 [2]常州大学,江苏常州213016

出　　处：《震灾防御技术》2017年第1期177-184,共8页Technology for Earthquake Disaster Prevention

基　　金：常州市科技计划资助(CJ20159009)

摘　　要：竖向效应是近断层地震动的主要特点,竖向地震动对工程结构形成的P-Δ效应是造成结构破坏的主要原因。本文以单自由度体系为研究对象,选取汶川地震的近断层强震数据进行研究,分析竖向地震动所产生P-Δ效应的放大作用特征。分析结果表明汶川地震中,相比于中远场区域,近断层区域内竖向地震动作用所产生的P-Δ效应具有明显的放大作用,且近断层内这种放大作用具有普遍性;当自振周期一定时,不同台站获得地震动的放大系数离散性较小,主要分布于均值附近;其分析结果符合地震动的一般规律,分析结果合理。在此基础上建立了以均值为代表值的放大系数谱,可以与抗震设计反应谱结合使用,从而为活断层附近区域内的结构抗震设计问题提供定量化参考依据。Vertical effect is the main characteristic of ground motion in near fault, and the P-A effect caused by vertical ground motions is the main reason for the failure of engineering structures. In this paper, taking the single degree of freedom system as the object, strongmotion datum of Wenchuan earthquake in near fault region were selectedto study the amplification characteristics of P-A effect for vertical seismic action. Our results show that P-A effect caused by vertical ground motions had the obvious amplification which were universal in near-fault region of the Wenchuan earthquake. In comparing with the region of medium-field and far-field, amplification of ground motions obtained from different stations did not discrete very much and distributed near mean values. The analytic results accord with the general law of ground motion. Based on this, the amplification spectra which can be applied in seismic response spectra were built, and the quantitative criterion for structural seismic design in near-fault region was put forward.

关 键 词：近断层 P-△效应 放大系数 自振周期 放大系数谱 

分 类 号：P315.9[天文地球—地震学]