地震波倾斜入射下两相饱和土层响应数值模拟

基于Biot两相饱和多孔介质理论建立了频域内饱和土层的刚度矩阵,对从基岩倾斜入射地震波下饱和土层的波动响应进行了数值研究,入射波采取修正的Kanai-Tajimi谱。通过土层地表面处的水平以及竖直放大系数研究了在不同工况条件下土层的波动响应,研究结果表明,土层的波动响应在入射角接近临界入射角时达到峰值;土层的波动响应随着基岩埋深基以及土层阻尼比的增大显著减小;而土层与基岩的波速比对土层的波动响应的影响存在临界波速比,使土层响应达到极值。对于含有夹层的地质环境,研究了波动响应沿深度的分布,通过与均质土层下响应对比,显示非均质夹层能显著减小土层地表处的波动响应,尤其软夹层能较好地阻止入射波向上的传播。

Numerical simulation of saturated layered soil subjected to inclined seismic wave incidence

Based on Biot's two phase poroelastic theory,the stiffness matices of saturated soil is developed in frequency domain and then the dynamic responses for a multi-layered poroelastic soil subjected to earthquake seismic wave at inclined incidence from the bedrock is studied with numerical method,modified Kanai-Tajimi spectrum for incident earthquake wave is adopted.The amplification of soil surface with different conditions are compared,results show that for the seismic wave at inclined incidence from bedrock,the response of soil reaches the maximun when the angle of incidence reachs critical incident angle;the response of soil surface decreasing with the bedrock depth and damper ratio;while there's a critical value for velocity of soil-bedrock ratio that soil response get it's maximum.For soils with non-homo-genous middle layer,the response along soil depth was explicite given in this paper and conpared with homogenous soil,the response can be weaken by it,especially soft middle layer can impede the propagation of seismic wave from bottom notably.