基于K-NET强震台网的海底地震动特征初探  

Preliminary investigation of offshore ground motion characteristics based on the K-NET strong-motion seismic network

作　　者：钟紫蓝 郭佳希 张卜 倪博 赵鑫 ZHONG Zilan;GUO Jiaxi;ZHANG Bu;NI Bo;ZHAO Xin(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《世界地震工程》2023年第4期7-14,共8页World Earthquake Engineering

基　　金：国家自然科学基金面上项目(51978020);国家自然科学基金资助项目(52220105011)。

摘　　要：为了研究海底地震动的特性,本文基于日本K-NET台网,选取124次地震事件中,5个海底台站和6个陆地台站所记录的981条地震动记录。经过数据筛选与处理,对典型地震动参数、动力放大系数谱和竖向与水平谱比进行了分析。结果表明:海水的存在会削弱竖向地震动的高频成分,导致竖向峰值加速度和强震持时要显著小于水平向;海底场地条件对海底地震动有放大作用,则选用陆地地震动进行海洋工程抗震设计会低估地震荷载带来的影响;当周期0.1 s<T<0.8 s时海底地震动的动力放大系数谱大于陆地地震动,最大值要大于抗震规范设计值,沿用现有的陆地抗震设计规范展开海底工程建造存在风险。To investigate the characteristics of offshore ground motions,981 ground motion records recorded by 5 offshore stations and 6 onshore stations in 124 seismic events were selected based on the K-NET network in Japan.The typical ground motion parameters,dynamic amplification coefficient spectra,and vertical-to-horizontal response spectral ratio were analyzed after data screening and ground motion data processing.The results show that the weakening of vertical ground motion by seawater causes the vertical peak acceleration and duration to be significantly smaller than the horizontal.The seabed site conditions have an amplifying effect on offshore ground motions,then the selection of onshore ground motions for seismic design of marine engineering will underestimate the impact of seismic loads.When the period 0.1s<T<0.8s,the dynamic amplification factor spectra of offshore ground motion is larger than that of onshore ground motion.And the maximum value of the dynamic amplification factor spectra of offshore ground motion is larger than the values of the seismic design code spectra,and it is risky to use the existing seismic design code to start the offshore construction.

关 键 词：海底地震动 地震动参数 放大系数谱 峰值加速度比 

分 类 号：TU443[建筑科学—岩土工程]