Theoretical analysis of adaptive precise control of high-speed railway track under the action of fault dislocation

The operational deformation tolerance of high-speed railways demands millimeter-scale precision, which starkly contrasts with the meter-scale fault displacements commonly observed in seismic events. Resolving this critical conflict between infrastructure resilience and tectonic deformation remains fundamental to ensuring railway safety. On 8 January 2022, a magnitude M6.9 earthquake (epicentral depth: 10 km; seismic intensity: IX) struck Menyuan County, Qinghai Province, China. This event induced significant fault dislocation that severely damaged the Daliang tunnel on the Lanzhou-Xinjiang high-speed railway, leading to track warping deformation. Aiming at the adaptive precise control of high-speed railway track under fault dislocation, the research was conducted using the Daliang tunnel as an engineering case study. Key findings include: (1) The theory and technology of the trajectory adaptive precise control under strike-slip fault dislocation are established, with the motion trajectory equations of bearing center and boundary tangent points derived. (2) Based on the project’s actual dimensions, a 1:10 scale-down model of the control device was fabricated, followed by physical simulation tests to validate the accuracy of the regulation theory. (3) Parametric analysis identifies the distinct geometric effects of bearing radius, bevel gear radius, initial moment arm, and lead screw stroke on the sliding groove curve. Comparative analysis reveals that the condition that the initial force arm multiplied by the transmission coefficient equals 1 yields the optimal sliding groove geometry, achieving simultaneous reductions in structural thrust and bending moment while maintaining bearing mobility through minimized curvature discontinuities. These findings play an important supporting role in the high-quality construction of high-speed railways.