非一致地震动输入下高面板坝地震反应特性

Dynamic response of high CFRDs under non-uniform seismic waves input

  • 摘要: 为研究地震波非一致输入对三维高面板坝动力反应的影响,采用波场分离的思路将人工动力边界处的总波场分解为无局部场地效应影响的自由场和局部场地效应引起的散射场,借助黏弹性边界建立地震波在自由场作用下地震动非一致输入,实现考虑地基辐射阻尼和地震波行波效应的地震动输入。对我国西南地区某高面板坝进行非一致地震动反应分析,研究P波和SV波作用下坝体结构的动力反应规律。结果表明:当P波非一致输入时,随着入射角度的增加,竖向加速度和动位移极值逐渐减小,水平向加速度和动位移极值逐渐增大;SV波非一致输入时,地震动反应规律与P波入射时相反。入射角度对地震波的行波效应以及坝顶加速度反应谱幅值等都有较显著的影响。

     

    Abstract: In order to study the influences of the oblique incidence seismic waves on the seismic response of the high concrete face rockfill dam, a total wave field of the artificial boundary is separated into free field without local topography effects and scattering field caused by local topography effects according to the thought of wave field decomposition. The seismic input method considering the non-uniform ground motion under the free field is established based on the viscoelastic artificial boundary. Furthermore, the influences of radiation damping of the infinite foundation and traveling wave effects are also realized by the method. The dynamic response analysis of a high concrete face rockfill dam under the actions of different incident waves and the incident angle is made, and studies of a dynamic response rule of the dam under the action of plane P wave and SV wave are carried out. It is found from the results of the dynamic response that the oblique incidence seismic wave is significantly different from the vertical incidence. With the increase of the incident angle of incident P wave, the peak acceleration and the peak displacement in the horizontal component is gradually increased, while the peak acceleration and the peak displacement in the vertical component is gradually decreased, which is opposite to the case of incident SV wave. The safety of the high concrete face rockfill dam cannot be ensured if only considering the influences of the vertical incidence. At the same time, the traveling wave effects and the amplitude of the acceleration response spectrum on crest of the dam are also influenced by the incident angle.

     

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