Objective At present, research on the shield tunneling construction crossing adjacent railway structures in karst strata is relatively scarce. There is an urgent need to conduct specialized analysis on such engineering problems.

Method Taking a shield tunneling project crossing a railway bridge in a karst stratum of Guiyang Rail Transit Line 3 as an example, a numerical simulation method is adopted to analyze the deformation and stress changes of the railway bridge caused by shield tunneling construction in the karst stratum. A comparative verification is also conducted combining on-site monitoring data.

Result & Conclusion  The numerical simulation method can effectively reflect the deformation of the railway bridge during the shield crossing and the stress changes in the bridge body after the shield crossing. When conducting shield tunneling construction simulations in karst strata, a relatively larger stress release rate of the surrounding rock can be selected for calculation; under hard rock karst stratum working conditions, the shield stress release rate can be set to 60%. Before shield tunneling crosses important buildings （structures） in karst strata, karst defects within the affected area should be pre-treated to avoid sudden risks during the tunneling process. On the basis of implementing effective prevention and control measures, the deformation impact of shield construction on the railway bridge is kept at a controllable level.