Prediction of ground vibrations induced by rail traffic in Lisbon urban area.

The possibility of introducing high-speed trains in Portugal will challenge the regular train circulation of existing railways tracks. To carry this traffic, improvements and maintenance programmes will be intensified together with the evaluation of the railway performance and its consequences on neighbourhood structures, including the execution of several vibration measurement tests. One of them was performed in Lisbon's urban area for measure of ground-borne vibration due to the train traffic. It was used to develop an efficient numerical model, which allowed to study the influence of introducing high-speed vehicles on the generation and propagation of vibrations through the free field and the impact on the wayside buildings. To access the effect of introducing such trains in the existing tracks, three bi-dimensional numerical models for each measurement profile were developed. Numerical models were calibrated using the monitoring records. Then, new simulations were performed with Thalys train allowing to conclude that the introduction of high-speed trains will not lead to an increase of level of vibrations, for the adopted traffic conditions.