建立了北京盆地含起伏地形的地下介质三维速度结构模型,以有限差分方法对盆地内的3次地震动进行了数值模拟.计算了地表加速度反应谱,论证了反应谱的有效周期范围,从而获得了盆地结构对长周期段反应谱的平均放大系数,并对不同周期时反应谱的平均放大系数进行了分区,为今后城市的合理规划和长周期建筑物的建设提供了抗震设防参考.最后对反应谱平均放大系数与等效沉积物厚度之间的关系进行了回归,得出了反应谱放大系数随沉积物厚度增大而增强,以及随周期增大而减弱等结论.%We built an underground 3-dimensional velocity structure model including topography, and simulated three earthquakes spreading through the basin by finite difference method. Then we computed the ground acceleration response spectrum, and analyzed its effective period span, and acquired its average amplification factor on long-period part, which is related to basin structure. After that, we made the zonation of amplification factors on different period, giving seismic fortification references for planning rational city layout and building long-period structures. Finally, we studied the relationship between amplification factor and sediment thickness, and drew the following conclusions: the amplification factor is increasing with thickness of sediment, and degrading with period.
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