Effects of High-Speed Railway Embankments on Free-Field Vibrations

Train induced vibrations have always been a matter of major concern for railway engineers. In addition to the track high maintenance costs, excessive ground born vibrations may cause annoyance to people who live in the track neighborhood. One potential solution toward minimizing these effects is the use of soil embankments as an efficient method for vibrations reduction.A review of the literature clearly shows that the effects of embankment parameters, namely thickness, stiffness and damping, on track response, have not been explicitly discussed. Because of considerable mass and stiffness of an embankment, the study of track behavior, while it is located on the embankment, is of great importance and necessitates more detailed analyses. This paper investigates the influence of embankment parameters on vibrations induced from train dynamic loads. For this purpose, the widely used finite element program, ABAQUS, has been employed to perform continuum analyses. Train loads have been introduced as the step loads and infinite elements have been used to simulate the infinity of the surrounding environment. The model has been verified with field measurements conducted on a high-speed railway track; the results show that the model is valid.As part of the study, sensitivity analyses have been performed on track parameters namely embankment height, stiffness and damping and on the train parameters including axle load and speed. The results of the numerical modeling and the sensitivity analyses reveal that among the aforementioned parameters, embankment height, train speed and axle load have remarkable effects on the track dynamic response.