Investigation into the Impacts of Cover-and-Cut Top-Down Metro Station Construction on Adjacent Buildings: A Case Study

Based on the inspection results of existing structures, this study conducts a safety evaluation of buildings adjacent to a 17.2–23.2 m deep metro station. Stratum loss induced by the deformation of the foundation pit retaining structure leads to displacement and stress redistribution in the surrounding strata, which in turn triggers displacement and deformation of adjacent existing structures. Numerical models were established to quantitatively assess the impacts of cover-and-cut top-down construction on adjacent structures, predict surface settlements during construction through numerical simulation, and formulate control measures to prevent foundation pit safety accidents. This research focuses on the influence mechanism of each construction stage of the cover-and-cut top-down method in Changchun Metro on the settlement patterns of surrounding soil and adjacent buildings, and puts forward targeted recommendations regarding monitoring, construction practices, and emergency early warnings. During the excavation and support of the station’s main foundation pit, the maximum peripheral surface settlement reached −9.804 mm, with a maximum horizontal deformation of −4.345 mm. For adjacent buildings, the maximum structural settlement was −4.243 mm, horizontal deformation 0.929 mm, and inclination rate 0.0107‰—all deformation indices remained within safe thresholds. The findings provide empirical data and technical references for safety assessment and risk control of existing structures adjacent to deep foundation pit engineering.