半空间异质隆起的出平面动力响应:地表运动  

Out-of-plane dynamic response of a heterogeneous hill in half-space: surface ground motion

作　　者：李雨润[1] 袁晓铭[1] 孙锐[1] 

机构地区：[1]中国地震局工程力学研究所,黑龙江哈尔滨150080

出　　处：《地震工程与工程振动》2005年第5期17-23,共7页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(49974011)

摘　　要：采用闭合解析解对水平地表圆形非匀质隆起出平面运动特征进行详细分析。结果表明:(1)隆起区域介质软硬程度对其出平面地表运动影响非常大,软质隆起表面的地表位移较匀质隆起情况有显著放大,地表运动波动效应明显增强,而硬质隆起则减弱地表运动;(2)软质隆起地表位移幅值最大反应和平均反应增大的程度一般来说至少不低于隆起区域波速降低的程度,很多情况是远大于波速降低的程度,但最大反应出现的位置和频段主要受入射波角度控制;(3)当波垂直传播时,地表位移放大出现在隆起顶部,频率随隆起区变软,明显向低频移动,可出现在很低频段内,且随隆起区变软放大更为显著;(4)当波掠入射时,地表最大位移出现在隆起后表面,地表运动仍然十分强烈,甚至比波垂直入射时隆起顶部反应还要大,但出现在较高频段内。Out-of-plane surface ground motion of a semi-cylindrical heterogeneous hill is presented using the closedform solution. The results indicate： （1） The effects of rigidity of the hilly region on the surface ground displacements of the hill and its adjacent region are significantly strong and the soft hill amplifies the surface displacements, while the hard hill decreases the surface displacements. （2） Generally, the amplification of the surface displacements of the soft hill increases at least to the same extent of wave speed decline of hilly region and in most cases, the increasing degree of amplification of the surface displacements is much larger than the decreasing degree of wave speed of hilly region. （3） For the vertical incidence of the waves, the obvious amplification of the surface displacements appears on the top of the hill in the quite low frequency range as the rigidity of hilly region decreases; （4） For the grazing incidence of the waves, the obvious amplification of the surface displacements appears on the back top of the hill in the higher frequency range and the amplification degree is even larger than that on the hill top.

关 键 词：半空间 非匀质隆起 出平面地表运动 地表运动 隆起区 动力响应 平面 异质 地表位移 运动特征 

分 类 号：P315.3[天文地球—地震学] P618.110.2[天文地球—固体地球物理学]