Abstract：The process of pile driving in saturated clay is modeled by the theory of expansion of cylindrical and spherical cavities in an infinite medium. The soil is assumed as a homogenous，isotropic and ideal elasto-plastic material. Solutions are presented for the stress distribution of the soil around pile surface during pile driving. Changes of soil properties around pile surface and its effects on the soil stress due to pile-driving are analyzed. Using the theory of hydraulic fracture，radial and vertical distributions of excess pore water pressure are subsequently studied along the pile surface during and after pile driving. A comparison of predicted and observed values shows good agreement.
