Dynamic Deformation of Railway Tunnel Bedding Structure

Four models of the tunnel bedding structure were analyzed under the impact loads of the train by simulating the infrastructure under the track. In this study, we examined the relationship between the vertical dynamic coefficient and the train velocity, and also analyzed the damage sustained by the bedding structure under the static and dynamic loads. It is suggested that the damage in the concrete bedding is detected in the longitudinal direction, immediately below the two rails, and that this damage is likely to occur not from attaining an elastic limit under static loads but more likely from damage accumulation in fatigue due to repeated loadings. It is not advisable to improve the tunnel bedding structure by simply increasing the thickness of the concrete bedding board; however, the bending resistance of the tunnel bedding structure can be enhanced by adopting compact reinforced concrete structure.