Analysis of the performance of a ballasted track in a transition zone

Resumo

The transition zones are characterized by an abrupt change in track support stiffness, which increases
dynamic wheel loads and leads to the acceleration of differential settlement and track degradation. Inefficient
performance of the transition zones is a major concern of the Railway Infrastructures Managers since the
degradation of the track in these areas is the cause of the generation of noise, vibration, poor ride comfort, higher
risks of derailment, and a decrease of the train speed. Since the performance of the ballasted track decreases
significantly in a transition zone, this work aims to study its short and long-term behaviour with a focus on a
transition between a ballasted and slab track. The analysis uses a hybrid methodology, combining an iterative
procedure between a 3D finite element modelling with empirical settlement equations. The FEM is capable of
simulating train-track interaction. At each iteration, the track-ground stress fields are calculated using a 3D model.
The stress results are the main inputs of an empirical equation capable of computing settlement across the
transition. The model is used to analyse settlement and stresses for a transition zone case study, which is crucial
to understand the response of the ballasted track in such areas.