淤砂层模拟方法对上层理想流体动力反应的影响——平面P波入射

采用解析法,以弹性半空间-淤砂层-理想流体层为对象,分别将淤砂层模拟为固体介质和流体介质,分析了平面P波入射时上层理想流体的动力反应特性。通过算例分析,比较了将淤砂层模拟为弹性固体、黏弹性固体、理想流体和黏性流体介质时与将淤砂层模拟为两相多孔介质时计算结果的差异。研究表明当渗透系数很小时,多孔介质可以近似简化为黏弹性固体,甚至线弹性固体。这一分析研究对于在高坝-库水-淤砂-地基系统地震反应分析的数值模型中采用合理的淤砂层模型,提高计算效率具有重要参考意义,而且还可以用于校核数值模型的合理性。

Effect of sediment model on dynamic pressure in overlying ideal fluid due to P wave incidence

Through the analytical solutions, the effects of saturated and unsaturated sediment on the dynamic pressures in the overlying ideal fluid due to P wave incidence from underlying elastic half-space are investigated. The sediment is modeled respectively as elastic solid, viscoelastic solid, ideal fluid and viscous fluid. The results obtained are compared with the case in which sediment was viewed as a two-phase poroelastic media. It is concluded that the two-phase poroelastic media can be simplified approximately as a viscoelastic or even as linear elastic solid when its permeability is relatively small (k≤10-3m/s). The findings are useful for construction a sediment model in dynamic analysis of dam-reservoir-sediment-foundation system to enhance the efficiency of the numerical procedures.