Characteristics and Mitigation Measures of Floor Heave in Operational High-Speed Railway Tunnels

Abstract

The rapid development of high-speed railway tunnels has resulted in the increased application of ballastless track slabs. However, floor heave induces ballastless track slab deformation as a result of surrounding rock pressure, imposing serious challenges to the safety of railway systems. In this study, the characteristic of floor heave was analyzed based on field monitoring data. A new tunnel lining structure was then proposed to reduce the effect of floor heave on the slab track. The stress and deformation characteristics of the lining structure under different floor heave loads were analyzed through three-dimensional load structure numerical simulation, and the adaptability of the new tunnel lining structure was numerically studied. The results show that the floor heave typically occurred in the deep-buried sections of tunnel and the maximum floor heave was less than 50 mm during the operation of high-speed railway tunnels. When the new type of tunnel lining was adopted, the influence of the floor heave on the slab track was very small due to the reserved groove of the upper part of the invert and the high rigidity of the steel-reinforced concrete slab, thus effectively reducing the deformation of the tunnel floor heave. This research can be beneficial in the structural design of high-speed railway tunnels and the prevention of tunnel floor heave.