Abstract: As a result of urban development, a deep excavation for the viaduct construction utilized the open cut with a slope of 1H:1V. In order to ensure the safety of the viaduct substructure during the excavation, the investigation and analysis of the surrounding environment of the viaduct are used before the analysis. The finite element analysis software MIDAS GTS was used to simulate the construction process of soil layer, structure and excavation. The results show that the displacement, internal force and stress in the piles of for the viaduct structure before and after the deep excavation are not significantly changed. The axial capacity of the pile is almost unchanged compared with that of before the excavation. The axial pile capacity of the single pile meets the code requirement. Therefore, the numerical analysis provides a viable support for the safe excavation. At the same time, during excavation, it is necessary to monitor the vertical and horizontal deflections at the bridge piers and working shafts.

Key words: Viaduct, Deep Excavation, Safety Analysis, Construction Monitoring