实际情况下基础都有一定埋深,这将改变土体中的散射波场并最终影响地基-基础的动力相互作用.运用Biot波动方程理论,研究了平面波作用下饱和地基中埋置刚性圆形基础的竖向振动.引入Novak模型,将基础侧面的上覆土层视为由若干极薄饱和圆环层组成,将基底视为饱和半空间.考虑基础侧面对入射波的散射,利用沿基础侧面的积分方法得到基础侧面的土体作用力.考虑基底对入射波的散射,结合基底与饱和半空间接触面的混合边值条件,建立两组描述刚性圆形基础竖向振动的对偶积分方程并求解得到基础底面的土体作用力.结合基础刚体动力平衡方程,求得埋置基础在入射波作用下的竖向振动位移表达式.数值结果表明:随着基础埋置深度的增加,其共振振幅减小明显.
In practice, the embedded depth of the foundation will change the scattering wave field and eventually influence the dynamic interaction between the soil and foundation. Based on the Blot's theory, an investigation was put on the vertical vibrations of the circular foundation embedded in poroelastic soil excited by plane waves. The Novak model was introduced. Namely, the soil along the foundation vertical side is composed of series of infinitesimally thin poroelastic layers, and the soil under the foundation base is regard as the poroelastic half space which independent of the overlying soil. Considering the waves scattering by the foundation side, the force acting on the foundation side can be obtained by the integration along the foundation side. Considering the waves scattering by the foundation base and the mix boundary conditions between the foundation base and the poroelastic half-space, the force acting on the foundation base is derived by the dual integral equations. Combining the dynamic equilibrium equation of the foundation, the expressions of the vertical vibration amplitudes of the embedded foundation subjected to the incident waves were acquired. Numerical results demonstrate that the resonance amplitude of the foundation decreases with the increasing of the embedded depth.