摘要
建筑物与工程场地之间发生共振效应,是产生震害的一个主要原因。为了使建筑物避免与场地发生共振,开展工程场地自振特性的研究是非常必要的。但是,目前对场地自振特性研究普遍将下卧层基岩视为绝对刚性体,忽略场地土体与其下卧基岩之间的相互作用,这一假设与实际情况并不相符。为此,本文提出一种可以考虑基岩影响的计算场地自振周期方法。该方法假定场地基岩为无限大半空间弹性体,将不同周期简谐波作为从基岩入射至土层中的地震波,应用界面子波方法计算地面地震反应,根据最大反应值与谐波周期组成的反应谱确定场地自振周期。为了区别于地震工程中单自由度体系的地震反应谱法,本文称此计算方法为谐波激励谱法。应用此方法计算了某工程场地的自振周期,所得计算结果与文献资料非常吻合,据此验证了此方法的正确性。在此基础上,通过改变基岩波阻抗参数,计算得到考虑基岩影响的场地自振周期,研究了基岩对场地自振特性的影响。研究表明,尽管基岩变形性质不会影响场地自振周期的取值,但是却增大了其影响范围,对设计建筑物避让场地自振周期带来不利的影响。
The resonance effect between the building and its site is one of the main reasons for the earthquake hazards.It is essential to study the natural vibration properties of the site to avoid resonance.However,the underlying bedrocks are generally regarded as an absolute rigid body when the conventional methods are used to ascertain the natural vibration properties of engineering sites.It is not always conformed with factual cases for which the interaction between rock and soil is neglected.For this reason,a method for calculating the natural vibration period of sites is presented,which can be used to consider the effects of the bedrock.The method can achieve the response spectrum composed by the maximum response value and the corresponding harmonic cycle,with maximum response values calculated by the interfacial wavelet algorithm under the action of different periods of harmonic wave from the bedrock,which is assumed as an infinite elastic half space.The response spectrum is called harmonic exciting spectrum with which to distinguish the seismic response spectrum for the single degree of freedom system in earthquake engineering.The method is used to calculate the natural vibration period of a project site,with the calculating results agreeing with the reference data.By changing the wave impedance parameters of bedrock,the natural vibration properties of the site considering bedrock effect are studied.Research shows that the values of natural vibration period of the site is not affected by bedrock deformation,but it can expand its influence scope.The conclusion is of adverse effects on building design avoiding resonance effect.
作者
范留明
谢超
赵钦
FAN Liuming;XIE Chao;ZHAO Qin(School of Civil Engineering and Architecture,Xi＇an University of Technology,Xi＇an 710048,China)
出处
《西安理工大学学报》
CAS
北大核心
2018年第2期172-177,共6页
Journal of Xi'an University of Technology
基金
陕西省社发攻关资助项目(2012K12-03-05)
关键词
自振周期
谐波激励谱
界面子波
基岩影响
natural vibration period
harmonic exciting spectrum
interfacial wavelet
bedrock effect
