层状土壤地震超表面对地震波的衰减性能  

The Attenuation Performance of Seismic Metasurface in Layer Soil

作　　者：陈昌强 赵春风[1] 曾超 王波[1] CHEN Changqang;ZHAO Chunfeng;ZENG Chao;WANG Bo(College of Civil Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学土木与水利工程学院,安徽合肥230009

出　　处：《土木工程与管理学报》2023年第1期114-123,共10页Journal of Civil Engineering and Management

基　　金：国家自然科学基金(52278302,51508148)。

摘　　要：针对低频瑞利表面波,利用周期结构的带隙特性,设计了层状土壤上地震超表面波屏障。通过理论推导和有限元方法获得并比较了地震超表面中垂直谐振器的表面波频散关系,揭示了谐振器与瑞利波的耦合机理。此外,研究了有限长度超表面的衰减特性和力学行为,讨论了谐振器质量和超表面长度对表面波衰减性能的影响。在此基础上设计了频率递减的梯度地震超表面,并进行了频域和时域分析。结果表明:有限元模型的数值解与解析解吻合较好,一阶表面模式在共振时会与谐振器发生强耦合,其余的高阶表面模式会穿过均匀介质中存在的表面波带隙;有限长度超表面在谐振频率处可以显著减小输出表面的地震动;合理增加谐振器质量或超表面长度可以实现表面波宽带衰减;梯度地震超表面拥有更宽的衰减区和更显著的衰减效应。For low-frequency Rayleigh surface waves, a seismic metasurface wave barrier on stratified soil is designed by using the band gap characteristics of periodic structure. The surface waves dispersion relation of vertical resonators in seismic metasurface is obtained and compared by theoretical derivation and finite element method, and the coupling mechanism between resonators and Rayleigh waveswas is revealed. In addition, the attenuation characteristics and mechanical behavior of the finite length metasurface were studied, and the effects of the resonator mass and the metasurface length on the attenuation performance of surface waves were discussed. On this basis, a gradient seismic metasurface with decreasing frequency was designed and analyzed in frequency domain and time domain. The results show that the numerical solution is basically consistent with the analytical solution, revealing that only the first-order surface mode is strongly coupled with the resonators at resonance, and the surface wave band gap reported in homogeneous medium is crossed by the remaining higher-order surface modes. The finite length metasurface can significantly reduce ground motion on output surfaces at resonant frequencies. Broadband attenuation of surface waves can be achieved by reasonably increasing the resonator mass or metasurface length. The gradient seismic metasurface has wider attenuation zone and more significant attenuation effect.

关 键 词：地震超表面 瑞利波 频散关系 宽带衰减 

分 类 号：TU435[建筑科学—岩土工程]