层状饱和土体中排桩对简谐荷载隔振效果分析

根据Biot理论，利用已有的传递、透射矩阵法得到层状饱和土体内部受竖向圆形分布荷载作用下的基本解，再由Muki虚拟桩法，建立了频域内层状土-桩的第二类Fredholm积分方程。通过离散方法求解积分方程，得到了评价隔振效果的振幅比。与已知文献结果比较，验证了方法的正确性。数值结果表明：对于同种类型的振源，采用相同的隔振系统，在上软下硬的多层土体中的隔振效果比在上硬下软的土层中要好。采用较长的桩或刚度较大的桩，或桩之间的距离加密都可得到好的隔振效果。

Vibration isolation using pile rows in a layered poroelastic half-space against vibration due to harmonic loads

Based on Biot's theory, the frequency domain fundamental solution for a vertical circular patch load applied to a layered poroelastic half-space is derived via the transmission and reflection matrices (TRM) method. Utilizing Muki and Sternberg’s method, the second kind of Fredholm integral equations describing the dynamic interaction between the pile rows and the layered poroelastic half-space subjected to a harmonic vertical load is constructed. The isolation effect of pile rows against the vibration due to the harmonic vertical load is investigated via numerical solution of the integral equations. Comparison of our results with an existing one shows that our results are in a good agreement with the existing solution. Numerical results of this study show that: a stiffer upper layer overlying a softer bottom half-space will worsen the vibration isolation effect of pile rows and vice versa. Also, pile rows with longer and stiffer piles or a smaller net spacing between neighboring piles in a pile rows are preferable for a better vibration isolation effect.