【摘要】 为揭示楔形空间中沉积谷地对地震动的显著影响,基于大圆弧假定,利用Fourier-Bessel波函数展开,采用一种新方法求解了楔形空间中圆弧形沉积对平面SH波的散射问题.首先利用2个大圆弧面模拟地表面,以方便构造地表面引起的散射波场.然后由连续性边界条件建立方程并求解得出该问题的解析解,通过同现有结果的对比,验证该方法的计算精度,进而进行详细的参数分析.计算结果表明,楔形空间中沉积附近地表位移反应特征依赖于波入射角、入射波频率、楔形夹角及沉积内外的材料特性,位移放大效应比半空间情况更为显著,因而需适当提高此类场地上建筑物的抗震设防标准.更多还原

【Abstract】 In order to understand the significant effect of the alluvial valley in wedge-shaped space on earthquake ground motion,a new method has been proposed in this paper to study the diffraction of plane SH waves by a circular alluvial valley in wedge-shaped space on the basis of large circle assumption with Fourier-Bessel series expansion technique.With two large curved surfaces simulating the ground surface,the scattering field was conveniently constructed.An equation was established with continuous boundary conditions and the analytic solution was derived.The accuracy of the proposed method was verified by comparison with the available results,and then detailed parametric analysis was carried out.The numerical results indicate that the surface displacement characteristics around the alluvial valley in wedge-shaped space depend on the angle of incidence,the frequency of the incident wave,the angle of the wedge,and the material properties of the media,and the displacement amplification effect on ground motion is more significant than that of the half space.It is suggested that the earthquake resistant level of the buildings built in such site should be properly enhanced.更多还原