Monitoring and numerical simulation of deep foundation pit of a subway station in Lanzhou

Based on the foundation pit of a subway station in Lanzhou, the horizontal and vertical displacements of pile top, surface settlement, axial force of steel supports and groundwater level of foundation pit during construction are monitored, and the monitoring data are analyzed. The monitoring results show that the horizontal displacement of pile top gradually changes from small to large and the vertical one of pile top increases with the increase of excavation depth, and the axial force of steel supports in the excavation process tends to be stable. Finally, the finite element software is used to simulate the excavation of the foundation pit. The simulated and monitoring results are compared. The results show that the numerical simulations and the monitoring results basically have the same variation rules. It is proved that the combined structure of steel tube bored pile and support is safe and feasible, and it ensures and maintains the stability of the foundation pit. This study may provide effective and reliable reference for the construction of similar foundation pits.