Objective While some specifications provide recommended control values for the clear distance between bridge piles and adjacent metro structures during construction, the influence mechanism of bridge pile construction on adjacent urban rail transit structures under varying horizontal clear distances remains unclear, requiring further investigation.

Method Taking the construction of a large vertical transportation road project adjacent to urban rail transit in Xi’an loess stratum as a case study, a three-dimensional numerical model is established based on the site conditions. The entire construction process is simulated to analyze the impact of bridge pile construction on adjacent shield tunnels, mined tunnels, and open-cut frame structures. The simulated values are compared with actual monitoring data to verify the effectiveness of influence mechanism for bridge pile construction on urban rail transit structures.

Result & Conclusion  The primary impact of bridges on urban rail transit occurs during the bridge pile construction stage. When the bridge pile length exceeds the burial depth of the urban rail transit structure, variations in pile length have a negligible effect on the deformation of urban rail transit structures. When the horizontal clear distance from bridge foundation piles and urban rail transit station main structures, open-cut auxiliary structures, and mined tunnels exceeds 4 m, and the horizontal clear distance to shield tunnels is greater than 5 m, the impact of bridge pile construction on urban rail transit structures is negligible. But when the horizontal clear distance falls below the above threshold values, it is necessary to verify the stress and deformation state of the urban rail transit structures, as well as the tunnel curvature radius, and relative curvature.