Soil and topographic effects on ground motion of a surficially inhomogeneous semi-cylindrical canyon under oblique incident SH waves
Soil and topographic effects on ground motion of a surficially inhomogeneous semi-cylindrical canyon under oblique incident SH waves
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斜入射SH波下表面不均匀半圆柱形峡谷地震动的土壤和地形效应
DOI：
10.1016/j.soildyn.2017.01.037
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发表时间：
2017
影响因子：
4
通讯作者：
Pak Ronald Y. S.
中科院分区：
文献类型：
--
作者：
Zhang Ning;Gao Yufeng;Pak Ronald Y. S.
为了阐明土体和地形联合作用对地面运动的放大作用，在经典弹性动力学框架下，推导了半圆柱形峡谷对斜入射面SH波的散射解析公式，该半圆柱形峡谷被局部非均匀土层覆盖，土层的弹性模数呈径向变化。以覆盖在峡谷圆面上的有限土层的剪切模数为径向距离的幂函数，推导了反平面剪切问题的运动控制方程，并用波函数展开法进行了解析求解。该方法可以有效地计算均匀和非均匀峡谷在斜入射波作用下的地面运动，并给出了一套完整的数值算例。研究发现，土层的不均匀程度和土层厚度对柱状峡谷表面地震动放大的大小和模式有影响，这取决于频率含量、不规则地形和入射波的倾角。
To elucidate the ground motion amplification due to combined soil and topographic effects, an analytical formulation in the framework of classical elastodynamics is derived for the scattering of oblique incident plane SH waves by a semi-cylindrical canyon covered by a local inhomogeneous soil layer with a radially-varying modulus. Allowing the shear modulus of the finite soil layer covering the circular surface of the canyon as a power of the radial distance, the governing equation of motion for the anti-plane shear problem is derived and solved analytically by the method of wave function expansion. The ground motions for both of the homogeneous and inhomogeneous canyons under oblique incident waves can be computed efficiently and a comprehensive set of numerical examples are presented as illustrations. The degree of inhomogeneity of the soil layer and its thickness are found to affect the magnitude and the pattern of ground motion amplification of the cylindrical canyon surface depending on the frequency content, the irregular topography and obliquity of the wave incidence.