Abstract: The settlement of pile foundation in deep soft soil for Beijing-Shanghai high-speed railway is calculated by using a pile foundation model established in FLAC^3D. When the creep effect of soil is considered, the soil parameters and creep parameters of pile foundation are inverted by using settlement-time curve obtained from pile settlement test under static load. Based on the inverted parameters, settlement of the pile foundation under long-term load is predicted. It's shown that the results of numerical back analysis are consistent with observed results. By predicting the pile foundation settlement  with inverted parameters, it's found that the settlements of both ungrouted piles and grouted piles are large in the early stage, approaching to the maximum, yet with no obvious creep effect in the later stage. Therefore, it's suggested that there is no need to reduce the creep effect by grouting and when the construction schedule is more intense, the reposing time of pile foundation can be decreased.

Key words: pile foundation, FLAC^3D, settlement, creep, back analysis, prediction