Ballasted Track Lateral Resistance Estimation by Discrete Element Method Simulations

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In this work, discrete elements methods (DEM) were used to simulate ballasted track lateral resistance problems by representing a granular material such as ballast as an assembly of rigid grains interacting through contact laws that contain micromechanical physics relevant for the material.Macro-mechanical properties, such as global resistance of the ballast bed, are then seen as a consequence of the collective dynamics of the assembly.A large number of lateral resistance tests simulations were run to find optimal value for frictional parameters so that experimentally measured values for various track configurations were satisfyingly found.The model was then used to explore the lateral track resistance of experimentally untested configurations, namely standard profiles and nonstandard ballast profile alike, for instance no shoulder, reinforced shoulder, "infinite" shoulder or walls.By varying the length and height of the shoulder, we could predict how much one can enhance the lateral resistance by adding more ballast on the side of the track, and what geometry is optimal for profile reinforcement in term of ballast quantity, while respecting security constraints toward lateral efforts due to potential rail buckling.