Excavation Optimization for Asymmetrical Deep Foundation Pits Adjacent to Subway Stations: Deformation Control and Safety Enhancement

With the rapid development of urban rail transit, the construction of subway stations and adjacent infrastructure plays a crucial role in urban modernization. This study investigates the excavation of asymmetrical, deep, and complex foundation pits near subway stations. Geological and hydrological conditions are integrated into the analysis by employing the hardening soil small strain constitutive model and incorporating groundwater drawdown simulations to account for real-world conditions. Using field monitoring and numerical simulations, the study analyzes the geological and hydrological conditions, as well as the deformation characteristics of existing structures under different excavation schemes. The results indicate that increasing the number of compartments significantly reduces deformation, especially in the horizontal direction, enhancing safety and stability. Furthermore, the stepped excavation scheme outperforms large-scale overall excavation schemes in controlling deformation, shortening construction periods, and ensuring safety. These findings provide valuable insights for similar projects and advance the understanding of foundation pit engineering.