P波垂直入射下海域岛礁场地动力反应分析  

SEISMIC RESPONSE ANALYSIS OF OFFSHORE REEF SITE UNDER INCIDENT P WAVE

作　　者：宝鑫[1] 刘晶波[1] 王东洋[1] 王建平[2] 郭东[2] 宋可 BAO Xin;LIU Jing-bo;WANG Dong-yang;WANG Jian-ping;GUO Dong;SONG Ke(Department of Civil Engineering, Tsinghua University, Beijing 100084, China;Engineering Design & Research Bureau of the Navy, Beijing 100070, China)

机构地区：[1]清华大学土木工程系,北京100084 [2]海军工程设计研究院,北京100070

出　　处：《工程力学》2019年第B06期1-7,共7页Engineering Mechanics

基　　金：国家自然科学基金项目(51878384,51478247);国家重点研发计划项目(2016YFC1402800)

摘　　要：该文重点研究P波垂直入射时海域岛礁场地的地震反应。截取包含岛礁礁体、海水以及下部基岩的近场计算域建立有限元模型,利用流体介质动力人工边界和一致粘弹性人工边界单元模拟无限海水介质与半无限地基的波动辐射效应。基于介质波动理论推导得到了P波垂直入射时含上覆水层的半空间自由场理论解,并利用基于人工边界子结构的地震波动输入方法,将该自由场运动转化为等效地震输入荷载,从而实现了海域岛礁场地P波垂直输入。通过算例分析,验证了该文模型与方法的准确性。并利用该地震反应分析模型研究海水与礁体的耦合作用以及水体中的波动输入对海域岛礁场地地震反应的影响。该研究可为海域场地地震反应分析提供一定的理论指导和方法借鉴。This paper focuses on the seismic response of a reef engineering site under vertically incident P wave.A near-field calculation domain including reef,seawater and bedrock is intercepted and a finite element model for a reef-seawater system is established,in which the wave radiation effects of the infinite seawater domain and the semi-infinite rock foundation are simulated by the dynamical artificial boundary for fluid medium and the consistent viscous-spring artificial boundary element respectively.The theoretical solution of the free field motion of a half-space model with an overlying water layer under normally incident P wave is derived based on the medium wave theory.Then,this free-field motion is converted into equivalent seismic input loads through the seismic wave input method based on the substructure of artificial boundaries.Thereby,the P wave is vertically inputted into the reef-seawater system and the seismic analysis model of the reef engineering site is proposed.The accuracy of the present analysis model is verified through numerical examples.Furthermore,this analysis model is used to study the influences of the coupling effect of the reef and seawater as well as the wave input in the fluid medium on the seismic response of a reef engineering site.This study can provide some theoretical and methodological insight for the seismic response analysis of marine engineering.

关 键 词：防灾减灾工程 工程场地地震反应分析 岛礁-海水系统 地震波动输入 流体人工边界 

分 类 号：P315.9[天文地球—地震学] TB123[天文地球—固体地球物理学]