地震动入射角度对地下结构地震响应的影响

考虑土-结构接触面效应和场地初始静应力影响,基于大型商用有限元软件ANSYS和粘弹性人工边界条件,采用动力松弛法的分析思路,建立了一种地震动斜入射条件下地下结构的接触非线性动力反应分析模型和方法,并讨论了地震动入射角度对地下结构动力反应的影响。结果表明:地震波斜入射使得结构的整体反应发生明显变化;随着入射角度的增加,节点的水平向应力反应明显增大,竖向应力峰值较小,增大程度也相对较小;节点的位移峰值随输入加速度峰值的增大也有一定的变化。因此,在分析近源地震作用下的地下结构动力响应时,需要考虑地震动的非一致输入问题。

The Effect of Obliquely Incident Seismic Waves on Dynamic Response of Underground Structures

Based on the visco-elastic artificial boundary and the finite element software ANSYS,seismic response of underground structures under oblique incidence is analyzed,considering the contact effect between soil and structures and the initial stress in site.The effect of obliquely incident seismic waves on dynamic response of underground structure is studied.The calculated results show that obliquely incident seismic waves make significant changes on the overall reaction of the structure.With the increase of incident angle,the horizontal stress of nodes increases significantly,and the peak vertical stress and the increment of the stress are all small.With the increase of input peak acceleration,the peak displacements of nodes have certain changes.Therefore,the effects of obliquely incident seismic wave need to be considered while analyzing the seismic response of underground structures near the epicenter.