Flac 2D was used to simulate pile installation and the subsequent consolidation, considering one dimensional consolidation in clay. The parameters selected for Flac code, such as initial effective stress and shear modulus of different stress history before installation, were analyzed. The effective stress and excess pore pressure of different overconsolidation ratio after installation were obtained. After the complete dissipation of excess pore pressure, the effective stress field around pile was generated. The effects of stress history, initial water content, initial shear modulus on undrained shear strength of soil were investigated, and the influence of soil structure on excess pore pressure after installation, and on radial effective stress and undrained shear strength after consolidation was also discussed. The traditional cavity expansion theory takes it as a plane strain assumption, which ignores the three dimensional nature of this problem.