海峡场地非线性地震反应特性的流-固弱耦合分析  

Nonlinear seismic response characteristic analysis of a cross-strait seabed based on a fluid-solid weak coupling method

作　　者：王彦臻 范宏飞 陈国兴[1,2] 赵凯 陈炜昀[3,4] WANG YanZhen;FAN HongFei;CHEN GuoXing;ZHAO Kai;CHEN WeiYun(Institute of Geotechnical Engineering,Nanjing Tech University,Nanjing 210009,China;Civil Engineering and Earthquake Disaster Prevention Center of Jiangsu Province,Nanjing 210009,China;School of Civil Engineering,Sun Yat-Sen University,Guangzhou 510275,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai Guangdong 519080,China)

机构地区：[1]南京工业大学岩土工程研究所,南京210009 [2]江苏省土木工程防震技术研究中心,南京210009 [3]中山大学土木工程学院,广州510275 [4]南方海洋科学与工程广东省实验室(珠海),广东珠海519080

出　　处：《地球物理学报》2025年第4期1352-1366,共15页Chinese Journal of Geophysics

基　　金：国家自然科学基金(51978334,52378347);国家重点研发计划项目(2022YFC3080400)资助。

摘　　要：海洋工程的抗震设计中海水对海床地表地震动特性的影响不容忽视.采用流-固弱耦合模型模拟海水-海床的相互作用,考虑海床地形效应及沉积土异质性,以广义non-Masing本构模型描述土的非线性滞回特性,模拟了跨琼州海峡海床场地的二维非线性地震反应特性.海床地表的地震反应特性受海水-海床的相互作用、地形效应、复杂软弱异质性沉积土和基岩输入地震动特性的综合影响.海水的影响使海床地表峰值加速度减小和地震动有效持时缩短,且对竖向地震动的抑制作用比水平向更为显著.海水抑制高频段(2.0 Hz附近)或放大了低频段(<0.5 Hz)内水平向、竖向地震动分量引起的海床类共振现象,且这种抑制或放大作用随基岩地震动的增大而增大.海床地表规准化谱加速度β(5%阻尼比)在海床场地的基本周期(0.25~1.1 s)段附近和长周期(>1.1 s)段的谱值分别减小和增大.The influence of seawater on seafloor motions cannot be neglected in the seismic design of offshore structures.On the basis of a recently proposed generalized non-Masing hysteretic constitutive model,a nonlinear seismic response analysis of the seabed site crossing the Qiongzhou Strait is developed using the fluid-solid weak coupling method.In the proposed seabed site response analysis,the seafloor topographic characteristics and spatially inhomogeneous seabed soils of the Qiongzhou Strait are considered in detail.The seafloor motion characteristics are comprehensively affected by the fluid-solid coupling effect between seawater and seabed,the seabed topography effect,the nonlinearity of seabed soils,and the characteristics of seabed-bedrock input motions.Due to the fluid-solid coupling effect of the seawater-seabed system,the peak accelerations at the seafloor are reduced and the significant durations of seafloor motions from seabed bedrock are shortened,and the suppression effect of seawater on vertical seafloor motions is greater than that on horizontal seafloor motions.Seawater attenuates or amplifies the resonance-like phenomenon at the seabed surface in the high-frequency bands(~2.0 Hz)or low-frequency bands(<0.5 Hz)induced by the horizontal and vertical seismic components,and the attenuation or amplification effect increases with the intensity of the input seabed bedrock motions.The 5%damping normalized spectral accelerationsβat the seabed surface decrease and increase,respectively,near the fundamental period(0.25~1.1 s)of the seabed site or long period(>1.1 s).

关 键 词：海床场地效应 琼州海峡 流-固弱耦合分析 土的非线性 地形效应 

分 类 号：P738[天文地球—海洋地质]