Objective The engineering of metro shield tunnel under-passing existing highspeed railway stations is of the highest risk levels among under-passing other railway projects, because its construction safety directly affects the operational safety of high-speed railways and the stability of various facilities. Therefore, it is necessary to accurately predict and systematically analyze the deformation law of major facilities within high-speed railway stations under such conditions, thereby to adopt scientific and reasonable construction control measures to ensure safety and control for the entire construction process.

Method Taking a metro shield tunnel project under-passing an operational high-speed railway station in China as a case study, the project overview is introduced, and a three-dimensional numerical model is established. At two construction stages—after completion of the right-line tunnel crossing and after completion of the bidirectional tunnel crossing, the vertical displacements of major facilities such as platforms, subgrades, and tracks caused by above-mentioned shield tunnel under-passing engineering are simulated and calculated, together with the horizontal and vertical displacements of platform canopy columns. Monitoring points are arranged on site, and the measured deformation values of various facilities are compared with the simulation results. Based on this comparison, the deformation characteristics of the platform, platform canopy, subgrade, and track of the high-speed railway station during shield tunnel under-passing are obtained, and corresponding monitoring and construction control measures are proposed.

Result & Conclusion  In hard plastic clay and completely weathered rock strata, when the burial depth of shield tunnel exceeds three times the tunnel diameter, all shield construction control measures must be strictly implemented, together with the deployment of an automated monitoring system. Under the condition without pre-reinforcement of the strata, the deformation of major facilities within the high-speed railway station remains controllable. The simulated and measured vertical displacements of the subgrade and track exhibit consistent trends and similar values. The measured and simulated values of platform vertical displacement show relatively large differences, while the deformation of canopy columns is mainly characterized by horizontal displacement.