Abstract：Due to soil large deformation and friction between pile and soil，cavity expansion method and strain path method can not simulate the dynamic penetration process of jacked pile；but finite element method has been widely used in the penetration process，solving the soil constitutive relationship，large deformation and interaction between pile and soil. An appropriate finite element model is given that accords with the actual process of jacked pile. This model adopts the rational constitutive model of soil and finite deformation theory. Through pile-soil interaction and displacement loading on pile top，the dynamic pile-sinking process is simulated. Horizontal and vertical displacement fields are studied through the finite element model. The effects of displacement fields caused by dynamic pile-sinking procedure are discussed；and moreover，the simulation results are compared with field test. The results show that compacting displacements are in accord with measured results；and further，change of compacting displacement can reflect the change of soil characteristic. During the installation of jacked pile，the horizontal compacting displacements increase with the increase of pile penetration depth；but for the vertical compacting displacements，the heave increases in shallow soil layers and settlement increases in deep soil layers with the penetration depth increasing. The maximum compacting displacement delays the pile-sinking depth，so it is necessary to put great emphasis on dynamic pile-sinking process.
