层状场地中二维沉积谷地对弹性波的三维散射

为研究层状场地中二维沉积谷地对斜入射弹性波的三维散射问题,建立了求解问题的移动间接边界元方法。方法通过沿二维沉积谷地轴线方向的傅里叶变换将三维问题降为二维问题,进而在沉积谷地截面内进行边界单元的离散和求解,求得截面内的三维动力响应,然后将截面内的计算结果沿沉积谷地轴线方向进行波数展开即可求得任意位置动力响应。文中通过与前人结果的比较验证了方法的正确性,并以均匀半空间场地和基岩上单一土层场地为例进行了数值计算和分析,给出了一些有益的结论。

Three-dimensional scattering by a two-dimensional valley embedded in a layered half-space

The indirect boundary element method(IBEM) is proposed to study the three-dimensional scattering by a two-dimensional valley embedded in a layered half-space.The wave-number transform has been applied in the valley’s axis direction to reduce the three-dimensional problem to a plane strain problem.The dynamic problem is solved in a section perpendicular to the axis of the valley,and the three-dimensional responses of the valley and the layered site are obtained from the inverse wave-number expansion.The validity of the method is confirmed by comparison with related results,and numerical results and analyses are performed by taking the amplification of obliquely incident plane waves by an alluvial valley in a uniform half space and in one soil layer over half-space as examples to give some useful conclusions.