Abstract: Taiyuan Street Station on Shenyang Metro Line No. 4 is located in a dense commercial district. The station’s transfer gallery spans more than 10 m, with a minimum soil cover of only 4.5 m. The construction area is tightly surrounded by surface buildings, underground shopping streets, existing metro stations, regional rail lines, and multiple entrances and exits. This paper examines the challenges posed by such a large-span underground excavation and proposes targeted engineering measures. It focuses on key techniques for environmental risk control, right-angle turning excavation, and large-scale openings in existing side walls. Measures such as soil reinforcement and isolation pile installation are implemented to minimize the impact of excavation on the sensitive surroundings. A lateral docking scheme is adopted to reduce the risks typically associated with right-angle steering in large-span underground works. Segmental ring-beam casting is used to enhance the safety of opening existing side walls. Numerical simulations and monitoring data confirm the effectiveness of these technical strategies. The experience gained provides valuable reference for similar future projects.

Key words: Complex Environment, Transfer Gallery, LargeSpan Underground Excavation, Risk Control