Influence of Pile-anchor Composite Support Structure on Excavation of Foundation Pit near Railway

Taking the foundation pit near the railway as the research object, the finite element software ABAQUS was utilized to establish the model of side pile-anchor composite support structure near the railway. The settlement of both sides of the railway, the horizontal displacement of pile top, and the settlement of pile top were simulated and analyzed, and compared with the monitoring results. The influence of pile anchor composite support structure on the excavation process of foundation pit was studied. The results show that with the excavation of foundation pit, the settlement on both sides of the railway gradually increases, develops rapidly in the middle stage and tends to be stable in the later stage. Both the monitoring and simulation results show that the horizontal displacement of pile top at the external corner is the smallest, which indicates that the arrangement of L-shaped pile at the external corner can effectively limit the horizontal displacement of pile and reduce the risk of instability. In the process of foundation pit excavation, appropriately increasing the locking value of the middle anchor cable can improve the support effect and reduce the risk. The numerical simulation and field monitoring results are in good agreement, and the numerical simulation can be used to guide the construction working status.