【摘要】 提出了一种考虑地震波散射效应的沉积河谷空间相关多点地震动模拟方法。基于弹性波传播理论,采用合理功率谱、相干函数和传递函数模型,借助原型谱表示法得到沉积河谷空间相关多点地震动,并验证了方法的可行性。其中,传递函数应用动力边界元法计算,可在很宽的频带内精细模拟沉积河谷中波型转换及聚焦效应。针对常见V型河谷开展了计算模拟,结果表明,河谷地形及松软沉积层对地震波传播具有显著影响,河谷地表地震动空间差异性十分显著,一维模型难以考虑地震波的散射及聚焦效应,从而会明显低估沉积内部部分区域的地震动峰值加速度。沉积河谷中大跨结构抗震设计宜采用考虑地震波散射效应的空间相关多点地震动输入。更多还原

【Abstract】 A simulation method for multi-point spatially correlated earthquake ground motions in sedimentary valleys, which considers the scattering effect of seismic waves, is proposed. Based on elastic wave propagation theory, a reasonable power spectrum, coherence function and transfer function model were used to obtain multi-point spatially correlated earthquake ground motions in sedimentary valleys using the prototype spectral representation method and then the feasibility of the method was verified. The transfer function obtained by the dynamic boundary element method can fine model the waveform conversion and focusing effect of sedimentary valleys in a very wide frequency band. The simulations for common V-shaped valleys were performed and the results show that the valley topography and loose sediments have a significant impact on the seismic wave propagation. The spatial variability of the earthquake ground motions in the valley surface is very significant. One-dimensional models can hardly consider the scattering and focusing effects of seismic waves. As a result, the peak acceleration of the ground motion within the interior of the sedimentary region will be significantly underestimated. Seismic design of large-span structures in sedimentary valleys should adopt multi-point spatially correlated earthquake ground motions input which considers the scattering effect of seismic waves.更多还原