海域地震动强度包络模型研究  

Study on Intensity Envelope Models for Offshore Ground Motion

作　　者：张超[1,2] 陈昽 武程 杜修力[3] 赖志超 王丕光[3] ZHANG Chao;CHEN Long;WU Cheng;DU Xiuli;LAI Zhichao;WANG Piguang(School of Advanced Manufacturing,Fuzhou University,Quanzhou 362200,China;School of Civil Engineering,Fuzhou University,Fuzhou 350108,China;School of Architectural Engineering,Department of Urban Construction,Beijing Institute of Technology(BIT),Beijing 100124,China)

机构地区：[1]福州大学先进制造学院,福建泉州362200 [2]福州大学土木工程学院,福建福州350108 [3]北京工业大学城建学部建筑工程学院,北京100124

出　　处：《防灾减灾工程学报》2024年第3期506-517,共12页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金面上项目(52178464)资助。

摘　　要：人工模拟地震动是目前开展海洋工程结构抗震分析的主要地震输入分析。强度包络函数是人工模拟地震动的重要参数,决定了地震动的强度非平稳性特性,并对地震动持时起控制作用。目前的地震动强度包络模型均是基于陆域地震动记录统计分析得出,无法准确反应海域地震动的强度特性。因此,基于日本K-Net强震动观测台网的实测地震数据库,分析海域地震动在时域中强度分布特性;提出适用于海域地震动的三段式强度包络模型,回归得到震级M、震中距R及关键参数上升段t_(1)、强震平稳段ts、下降段衰减率c(无量纲)的计算表达式;研究震级、震中距对海域地震动强度包络模型的影响规律,并探讨海域地震动与陆域地震动强度包络模型的异同。研究结果表明:海域地震动强度包络模型中关键参数上升段t_(1)、强震平稳段ts、下降段衰减率c的取值范围分别为[13~52 s],[12~79 s],[0.037~0.173];震级对关键参数(t_(1)、t_(s)、c)的影响要大于震中距;与陆域地震动相比,海域地震动的强度包络模型的下降段衰减率c相差显著,且各关键参数的分布范围更大。Artificially simulated earthquake motion is currently the main seismic input for seismic anal-ysis of marine structures.The intensity envelope function,a crucial parameter for artificial simulation of ground motions(GMs),determines the non-stationary intensity characteristics of GMs and controls the duration.Existing intensity envelope models,derived from a large amount of onshore earthquake GM records,cannot accurately reflect the intensity distribution characteristics of offshore GMs.There-fore,this study focuses on intensity envelope models for offshore GMs.Firstly,an offshore earth-quake GM database was established based on the records selected from the K-Net strong motion obser-vatory network in Japan.The intensity distribution characteristics of offshore ground motions in the time domain were studied.Secondly,this study proposed a three-stage intensity envelope model suit-able for offshore GMs.Computational expressions for earthquake magnitude M,epicentre distance R,and key parameters including the rising segment t_(1),the steady segment ts,and the decay rate of the de-scending segment c(dimensionless)were derived through regression analysis.Thirdly,the impact of earthquake magnitude and epicentre distance on the intensity envelope model for offshore GMs was in-vestigated.At last,the similarities and differences between the intensity envelope models suitable for offshore and onshore GMs were compared.The research results indicate that:the key parameters,in-cluding the rising segment t_(1),the steady segment ts,and the decay rate of the descending segment c,have ranges of[13 s~52 s],[12 s~79 s],and[0.037~0.173],respectively,for the intensity envelope model of offshore ground motions.The effect of magnitude on key parameters(t_(1),t_(s),c)is greater than that of epicentre distance.Compared with onshore ground motions,the intensity envelope model for offshore GMs differs significantly in the attenuation rate c in the descending segment,and the distribu-tion range of each key parameter is larger.

关 键 词：海域地震动 强度包络模型 衰减关系 三段式模型 相模湾地区 

分 类 号：P314.6[天文地球—固体地球物理学]