Metro Project based Analysis of Excavation Impact on Pile Bearing Capacity

Abstract:

Fast Lagrangian analysis of continua in three dimension (FLAC3D) was employed to investigate the effect on pile foundation after a staged excavation, which considered the relative slip between pile and soil and also realized the dynamic process of excavation, and the model was verified by the results of axial force changing in pile shaft, the maximum tension force in pile and its location through the comparative analysis between the measurement and calculate after the excavation, and then the impact on the bearing capacity of pile foundation was discussed. Results show that pile foundation is in tension state after excavation, the maximum tension is increasing and the location is moving downward with the excavation depth; the bearing capacity changes significantly after excavation, the normal stress along pile shaft decreases sharply after excavation, especially on the pile top, which will cause the loss of bearing capacity in pile foundation.

Key words:pile foundation; excavation; bearing capacity; finite difference method