Abstract:Due to the indispensable application of foundation pile in high backfill site, considering the influence of creep characteristics of high backfill soil on the mechanical properties of foundation pile during its use process, the finite difference software FLAC3D and the time effect are used to calculate the filling thickness of 10m and pile diameter of 1m.The foundation pile with rock-socketed depth of 3m was subjected to numerical simulation analysis with pile top loads of 0, 0.5MPa, 1MPa, 2MPa, 3MPa and 5MPa respectively, and the stress and deformation characteristics of foundation pile under different pile top loads were obtained. The results show that the settlement increases at first and then tends to balance with time, and the rate of pile top displacement changes with time under different pile top loads lags behind the settlement and deformation rate of pile top filling. At the initial stage of creep, the maximum internal force of pile accelerates, but the resistance of pile tip does not increase at this stage. As the creep of fill enters the middle and later stage, the pile tip resistance develops rapidly, and the lateral friction resistance transfers to the pile tip resistance. After the creep stability of the surrounding fill, the maximum axial force of pile is positively correlated with pile top load, but the added value of axial force of pile decreases with the increase of pile top load. Pile tip resistance and its added value also increase with the increase of pile tip load. The study can provide reference for the design and construction of pile foundation in high fill site.