Abstract: The Green functions of saturated soil derived from the Biot’s poroelastic dynamic equation are the results in u-w formulation, where u is a displacement of the solid phase medium, and w is an average displacement of the fluid phase relative to the solid phase. Decoupling fast and slow longitudinal waves with regard to Biot’s dynamic equation, the analytical solutions for the solid and fluid Green’s functions in u-P formulation, where P is the porous pressure of the fluid phase, subjected to an underground point source in a porous medium in frequency-domain are obtained respectively and readily in this paper. The effects of increasing roots of Green functions in the u-w formulation on BEM integration are eliminated. Through Hankel’s inversion and Somigliana’s representative integral over a half-space in numerical implementation, the displacement, porous pressure, water discharge and other corresponding results of dynamic response in the saturated soil are presented for discussing. It has important application value for the response calculation of subway and other traffic engineering, seismic engineering and structure-soil dynamic interaction (SSI).

Key words: numerical implementation, saturated soil, underground point source, displacement, porous pressure, water discharge, dynamic response