地下水位变化对地震地面运动的影响  

Effects of the groundwater level variation on earthquake ground motions

作　　者：李伟华[1] 赵成刚[1] 

机构地区：[1]北京交通大学土木建筑工程学院,中国北京100044

出　　处：《地震学报》2015年第3期482-492,532,共11页Acta Seismologica Sinica

基　　金：国家自然科学基金(51378058);中央高校基本科研业务费专项(2013JBM060)共同资助

摘　　要：本文以Biot提出的流体饱和多孔介质波动理论为基础,建立了成层地基模型,把地下水位以下的饱和土层用水饱和多孔介质模拟,地下水位以上土层用气饱和多孔介质模拟.通过研究入射平面简谐波在成层地基中的传播,分析了地下水位变化对地震地面运动的影响.结果表明:P波入射下,当土体骨架相对刚度较小时,地下水位变化对地表位移尤其是竖向地表位移幅值影响较大,随着地下水位的下降,竖向位移逐渐增加,相对应的峰值频率逐渐减小;当土体骨架相对刚度较大时,地下水位变化对地面运动影响不大.Based on Biot＇s theory of fluid-saturated porous media,this paper presents the effects of groundwater level variation on earthquake ground motions through the analyses of wave propagation in layered foundation.In this analysis,a layered foundation model is built,assuming the saturated soil layer below the groundwater level as water-saturated porous soil,and the soil layer above the groundwater level as air-saturated porous soil.Numerical results show that under the incident P wave,the groundwater level variation has larger effect on the amplitudes of ground surface displacement,especially on the amplitudes of vertical surface displacement when the relative stiffness of soil skeleton is small.With the decline of the groundwater level,the vertical surface displacements increase,and the frequencies at the resonance peaks decrease correspondingly.But when the relative stiffness of soil skeleton becomes large,the variation of groundwater level has little effect on earthquake ground motions.

关 键 词：地下水位 地震地面运动 流体饱和多孔介质 成层地基 

分 类 号：P315.31[天文地球—地震学]