Aerodynamic Behavior and Impact on Driving Safety of Spalling Blocks Comprising High-Speed-Railway Tunnel Lining

Abstract

The lining of operating high-speed-railway tunnels suffers from cracks, the peeling of material, and other deteriorations and defects, all of which seriously affect driving safety. However, the trajectory of a falling block from the tunnel lining in a tunnel train wind environment and its impact on driving safety are unknown. To study the movement of falling blocks under a coupling effect of tunnel train wind and the local flow field of the falling blocks, a three-dimensional gas–solid-coupling numerical calculation model of spalling blocks–train–tunnel–air was established using FLUENT software The aerodynamic evolution mechanism governing the spalling blocks of the lining was analyzed, and we found that the falling process of a spalling block is affected by the coupling of its own characteristics and transient train wind. Train wind directly induced the horizontal motion of falling blocks, generated curves and eddy currents, and changed the motion state of spalled blocks. Furthermore, by comprehensively considering the motion trajectories of flaky and blocky blocks at different positions, the impact of spalling blocks on driving safety was obtained. The dangerous area of spalling blocks was approximately 5.5 m above the ground, which must be paid attention to. Our results provide guidance for the operation and maintenance of high-speed-railway tunnels.

Keywords

• spalling blocks
• aerodynamic behavior
• traffic safety
• gas–solid-coupling model