层状非均质饱和土层波动响应研究

Dynamic response of saturated layered soils under seismic wave excitations

基于Biot两相饱和多孔介质理论,推导了层状饱和土的刚度矩阵,通过数值计算研究了饱和土层基岩埋深以及土层基岩的波速比等参数对基岩入射剪切波的波动响应影响,并与非均质复杂土层条件下的波动响应进行了对比研究。研究结果表明:与单相弹性土层相比,饱和条件下的土层波动响应受到土骨架与流体间的耦合作用波动响应显著降低;对基岩入射地震波,地表处的加速度放大系数随着基岩埋深以及基岩土层波速比的增大呈减小趋势;对于非均质复杂分布土层,在上软下硬条件下能加大土层的波动响应,反之则能显著减小土层的波动响应;对于含有中间夹层情况能明显减小土层的波动响应,尤其软夹层能极大削弱基岩剪切波向上的传播。

Based on the Biot＇s two-phase saturated porous media theory, the stiffness matrices of saturated soil is developed and then the dynamic responses with different bedrock depths and velocity of soil-bedrock ratios for a multilayered poroelastic soil subjected to earthquake shear wave incident from the bedrock is studied with numerical method, and also compared with the non-homogenous soil layers. Results show that compared with elastic single-phase medium, saturated soil can reduce dynamic soil response due to soil-water coupling effects. For the earthquake shear wave incident from bedrock, the acceleration amplification of soil surface decreases with the bedrock depth and velocity of soil-bedrock ratio, with non-homogenous distribution of soil layers, the response magnified with soil velocity that increased with depth and otherwise decrease, for the soil contain hard or soft middle layer which can reduce the response of soil notably, especially with the case of soft middle layer.