Evaluation of track stiffness with a vibrator for prediction of train-induced displacement on railway embankments

A measuring car, the rolling stiffness measuring vehicle (RSMV), has been developed to investigate track conditions. The investigation described in this paper firstly attempts to understand whether the point flexibility of the track, i.e., the track-embankment-subsoil system, can be obtained by simultaneously measuring the force applied to an axle of the measuring car and the resulting acceleration response. Secondly, it attempts to determine the physical properties of the track by modelling it as a Bernoulli–Euler beam on a Kelvin foundation. The final part of the paper investigates the possibility of predicting displacements on a railway embankment based on the physical properties obtained after a train passage. Results from two sites in Sweden, Kumla and Kåhög, have been used. Investigations give encouraging results. However, as seen here, it can be difficult to analyse and obtain parameters if the resonance frequency of the system is low. The peak particle displacement of the ballast on the railway embankment was achieved with fair accuracy for both Kumla and Kåhög using the results from the accelerometer on the RSMV.