Deformation characteristics of excavation of deep foundation pit at a metro station in Lanzhou

The horizontal displacement of the pile top, the horizontal displacement of the pile and the settlement of the ground surface in the deep foundation pit of a subway station in Lanzhou are monitored and analyzed. The results show that the horizontal displacement of pile top increases with the excavation of the foundation pit, and that of the pile tip close to the inner support is relatively smooth. With the increase of depth, the horizontal displacement of the pile presents the trend of “being first fast and then slow, first steep and then slow,” and there will be a maximum value at 2/3 points from the top of the pile. The more the ground settlement is, the faster the change rate is. Finally, the finite element software Geostudio is used to simulate the excavation of the foundation pit, and the numerical simulation results are compared with the monitoring ones. It is indicated that the results of numerical simulation and monitoring are close, and the law of change is basically the same. The reliability of the design scheme and finite element model is proved. It can provide a good reference for the design and construction of similar projects in the future.