The Mechanical Behavior of Short Board Track in Subgrade Section Under Normal Fault Dislocation

In mountainous regions with multiple fault zones, ballastless tracks were susceptible to damage and failure under the effect of fault displacement, which compromised their normal service performance and operational safety. In this study, a track-subgrade coupling model crossing fault zones was established using the finite element method and a concrete damaged plasticity model. The mechanical behavior of a novel short board track was compared with that of continuous and unit board tracks. The results showed that the vertical deformation and interlayer gap of the three tracks increased with increasing fault displacement. The short board track exhibited slightly greater rail deformation, with a vertical deformation amplitude approximately 1.12 times that of the other two tracks. In contrast, the maximum interlayer gap between the base board and the subgrade was larger for the continuous and unit board tracks than for the short board track. The concrete track structure of the short board track was not damaged under normal fault dislocation. In contrast, the damage variables for the concrete track structure of the continuous and unit board tracks increased with fault displacement. This study provided crucial guidance for selecting new ballastless track types for railways traversing multi-fault regions.