中文摘要：

间接边界元素方法(IBEM ) 被建立解决 3-D 的问题 2-D 地形学的地震回答，由与直接僵硬的方法计算免费地的回答并且与动态草地模仿散布波浪地，移动的功能散布了负担。建议方法产出精确结果，因为动态僵硬矩阵使用了的 3-D 是准确的，没有奇特，虚构动人的分布式的负担能在在冲积山谷和分层的一半空间之间的接口上直接被扮演。有出版方法的比较验证建议方法的有效性。并且数字分析被执行给一些有益的结论。学习证明由一条冲积山谷散布的 3-D 与 2-D 盒子实质上不同，并且土壤层的存在影响表面排水量的振幅价值而且表面排水量的分发不仅。

英文摘要：

The indirect boundary element method （IBEM） was established to solve the problem of 3-D seismic re- sponses of 2-D topographies, by calculating the free-field responses with the direct-stiffness method and simulating the scattering wave fields with the dynamic Green＇s functions of moving distributed loads. The proposed method yields accurate results, because the 3-D dynamic stiffness matrixes used are exact and the fictitious moving distributed loads can be acted directly on the interface between the alluvial valley and the layered half-space without singularity. The comparison with the published methods verifies the validity of the proposed method. And the numerical analyses are performed to give some beneficial conclusions. The study shows that 3-D scattering by an alluvial valley is essentially different from the 2-D case, and that the presence of soil layer affects not only the amplitude value of surface dis- placements but also the distribution of surface displacements.