| 圆弧形凹陷在SH波入射下瞬态反应的解析解 |
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| 引用本文： | 杨彩红,郝明辉,张郁山.圆弧形凹陷在SH波入射下瞬态反应的解析解[J].地震学报,2022,44(1):111-122. |
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| 作者姓名： | 杨彩红 郝明辉 张郁山 |
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| 作者单位： | 中国北京 100029 中国地震灾害防御中心 |
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| 摘 要： | 针对现有地震波散射问题的解析解均在频域内给出，其适用的频带较窄，不能获取到可靠的瞬态反应解析解的问题，本文利用宽频带频域解析解进一步获取了不同空间点地震反应的宽频带频响函数，并基于傅里叶变换得出SH波入射下圆弧形凹陷地形瞬态动力响应的解析解。以上述为基础，研究了输入脉冲与实际地震动时凹陷的瞬态反应的基本特征，并重点分析了凹陷对地震动的放大效应，该效应定义为凹陷周围不同空间点的地震反应参数，如其峰值和反应谱等与自由场（即弹性半空间）地震反应参数之间的比值。结果表明:输入脉冲时，凹陷角点位移幅值显著放大，该放大效应与入射角度和脉冲持时有关；输入实际地震动时，凹陷迎波面角点反应谱放大显著，地震动反应谱比最大值可高达2.0，且放大效应与凹陷几何参数和入射角度等因素有关。
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| 关 键 词： | 平面SH波 凹陷地形 散射 解析解 反应谱 |
| 收稿时间： | 2021-05-30 |
Analytical solution to the transient response of arc-shaped canyon incident by plane SH wave |
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| Yang Caihong,Hao Minghui,Zhang Yushan.Analytical solution to the transient response of arc-shaped canyon incident by plane SH wave[J].Acta Seismologica Sinica,2022,44(1):111-122. |
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| Authors: | Yang Caihong Hao Minghui Zhang Yushan |
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| Institution: | China Earthquake Disaster Prevention Center，Beijing 100029 |
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| Abstract: | The existing analytical solutions to scattering of seismic waves are presented in the frequency domain and valid only in narrow frequency band, from which the reliable transient solution cannot be obtained. Addressing this problem, this paper used the broad-band frequency-rdomain analytical solution to obtain the broad-band frequency-esponse function for different spatial locations, and by Fourier transform, presented the analytical solution to the transient response of canyon topography SH wave incidence. Based on this, this paper studied the fundamental characteristics of transient response of canyon under the inputs of impulses and real ground motions, with the emphasis on the amplifying effect of the canyon on ground motion. This effect was defined by the ratio between the parameters, such as the peak and the spectral acceleration, etc., of seismic responses around the canyon, to those of seismic responses of free field, i.e. the elastic half-space. It was demonstrated that, under the impulse input, the displacement of the canyon corner was amplified distinctly, which was related to the impulse duration and the incident angle. As to the input of real ground motion, the spectral acceleration on the corner at the incident side of canyon is significantly amplified, with the maximum spectral ratio being as high as 2.0, which is related to the canyon geometries and the incident angle. |
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