浅埋孔洞对地表反平面运动的影响

Effects of shallow buried cavity on anti-plane ground motion

采用复变函数和多极坐标方法,构造了一个能够自动满足水平表面上应力自由边界条件的散射波函数,研究了地下任意形柱状孔洞对任意角度入射的平面SH波的散射及其对地面震动的影响,给出了浅埋孔洞附近地面运动的数值结果。定量分析了入射波长、入射角度、孔洞的形状和埋深等因素对地面运动的影响。研究表明,浅埋孔洞与水平表面存在强烈的相互作用对局部地面运动将起到放大作用,在地面建筑物抗震设计时应考虑地下隧洞的存在对地震动的影响。

A scattering wave function satisfying zero-stress condition on horizontal surface is constructed by using the functions of complex variable and multi-polar coordinate system. The scattering of SH-wave with arbitrary incident angle by a subsurface cavity of arbitrary shape in half space is studied together with its influence on ground motion. Numerical results of the ground motion on subsurface cavity are provided. The effects of incident wavelength, incident angle, shape of cavity and buried depth on ground motion are analyzed quantitatively. The research indicates that great interaction exists between the subsurface cavity and the horizontal surface, which will bring about great influence on ground motion. Therefore enough importance must be attached to the existing of subsurface cavity while finishing seismic design for building.