Numerical Modelling of Jointed Rock Foundation Under Heavy Haul Train Loading

Railways are an important lifeline for mining and industrial based economy such as Australia. Railway tracks traverse a number of difficult terrains across the country such as jointed sandstone rock formations near Sydney region. In an economic point of view, it is necessary to reduce maintenance costs and improve the life span of railway tracks built on fractured or jointed sandstone. To address this issue, a numerical model is developed to simulate the behaviour of jointed rock under the passage of heavy-haul trains using FLAC 3D, and the response of a single joint under a moving axle load was simulated for simplicity. In this study, Barton and Choubey’s method for estimating shear strength of a rock joint was incorporated alongside the existing Coulomb frictional interface in FLAC 3D. The proposed method provides a practical approach to improve the Coulomb frictional interface by including Joint Roughness Coefficient. Further, this method also simulates the evolution of shear and normal stresses distinctly at different locations on the joint surface under train passage. Under a heavy haul train passage, the contours depicting normal stress and the related apparent friction angle are presented.