Abstract: Combined with the dynamic testing of pile foundation in a wind tunnel construction project, three-dimensional finite difference simulation software FLAC^3D is used to simulate the double-pile model foundation. The numerical results are in good agreement with the experimental data, which verifies the rationality of numerical method based on the pile-soil-structure interaction to solve the dynamic response of the pile foundation under the equipment load. The post-grouting model of cast-in-place pile is further established to explore the influence of different lateral resistance and tip resistance enhancement coefficients on the dynamic characteristics of the pile foundation. The results show that the post-grouting of cast-in-place pile has no influence on the resonance frequency of the vertical vibration. The post-grouting of cast-in-place pile has slight influence on the resonance frequency of the horizontal rotary vibration, the maximum amplitude, the shear stiffness coefficient of the foundation, and the first mode damping ratio of the horizontal turning of the foundation. The post-grouting of cast-in-place pile can improve the compressive stiffness and reduce the maximum amplitude of the pile foundation, but its effect is limited compared with the non-grouting pile.

Key words: post-grouting pile, dynamic characteristics test, interaction, numerical simulation