Abstract: Based on Biot’s porous media theory of saturated fluid, the wave function expansion method and Graf addition theorem are used to solve the vibration isolation problem of plane SV wave by periodically arranged pipe piles in saturated soil. In this method, the scattering problem of SV wave by infinite periodic piles in saturated soil is transformed into solving only one periodic element by using the characteristic that the scattering wave field of different periodic elements in saturated soil is only different in frequency domain. Therefore, it can solve the problem of SV wave scattering by infinitely periodic pipe piles in saturated soil into solving only one periodic element limit. On the basis of verifying the correctness of the method, the influence of the number of piles, the parameters of saturated soil, the thickness of pipe wall, the number of piles and the arrangement mode on the vibration isolation capacity are discussed. The results show that: (1) the vibration isolation capacity of periodically arranged pipe piles in saturated soil is better than that in elastic soil, and the vibration isolation ability is stronger in saturated soil with poor permeability; (2) the thickness of pipe wall should not be too thin, and when the ratio of inner diameter to outer diameter is about 0.6, the vibration isolation capacity of periodically arranged piles can be stable at most frequencies; (3) increasing the number of piles can significantly improve the vibration isolation capacity, which can be increased by about 20% in the low frequency range of dimensionless frequency 0?0.6, and 60% in the medium and high frequency range of dimensionless frequency 0.6?3.0; (4) the vibration isolation effect of rectangular arrangement of piles is better than that of plum shaped arrangement in the low frequency range of dimensionless frequency 0?1.0, and the other two arrangements have good shielding effect.

Key words: saturated soil, vibration isolation of pipe piles, periodic arrangement, wave function expansion method, plane SV waves