Optimization and Impact Assessment of Excavation Sequence around Subway Stations from the Perspective of Sustainable Urban Development

The construction of group foundation pits near subway stations often leads to environmental pollution, thereby causing certain damage to urban ecology. By optimizing the excavation sequence of group foundation pits, the adverse effects on surrounding underground structures and soil during excavation can be effectively mitigated, contributing to the sustainable development of cities. Taking a group foundation pit project in Changzhou as an example, this study utilized the finite element software PLAXIS 3D to simulate various working conditions under different excavation sequences, comparing the deformation of the subway station, shield tunnel, and surrounding soil. The results show that, influenced by the excavation of group foundation pits, the difference between maximum deformation and minimum deformation of shield tunnel is 25.85%, and the difference between the maximum deformation and minimum deformation of the subway envelope is 19.44%. The subway envelope is least affected by the change in excavation sequence. Both the displacement of the subway station and the surrounding soil exhibit a significant "cumulative effect", with displacement changes closely related to the distance from the pit to the station and the ground, as well as the amount of soil unloaded in each excavation. Therefore, it is advisable to adhere to the principle of "far before near, shallow before deep, small before large" during excavation, which facilitates the coordinated development of urban infrastructure construction and the urban ecological environment, providing valuable reference and guidance for the sustainable development of cities.