Numerical Analysis of the Dynamic Behavior of the Ballasted Railway Track Under Loading of Trains at Variable Speeds to Improve the Prediction of Dynamic Amplification Factors and Damage to Its Components

Abstract

This study contributes to the dynamic amplification effects of different speeds of trains on the behavior of the ballasted railway. The damage mechanisms of the main components of ballasted railway tracks were investigated in 3D numerical modeling using the PLAXIS code. Several moving speeds have been tested. The effect of speed is very remarkable on the ballast, whose vertical strains increase considerably with increasing speed and the same is true for stresses acting at the base of sleepers, including settlements. On the other hand, shear forces, bending moments, and internal stresses on the concrete sleepers increase slightly with increasing speed, as these are the indirect parameters for characterizing behavior. In the ballast layer, the increase in speed causes a considerable increase in vertical compressive deformation at the top of the compacted ballast layer due to the dynamic amplification factor. Damage calculations in concrete sleepers and compacted ballast have revealed that ballast is more vulnerable than sleepers. This vulnerability is even greater when speeds exceed 200 km/h. This result explains and justifies the regular reballasting of ballasted tracks so that the correct level of service is maintained. The main damage to the ballasted track is the rutting of the compacted ballast layer.