SEISMOGRAMS OF MOVING TRAINS: COMPARISON OF THEORY AND MEASUREMENTS

High-speed trains can generate strong vibrations that propagate away from the track. In this paper, an efficient method is presented to calculate the displacements, generated by a moving train. It is based on an integral representation of the response and is computed numerically in the slowness domain. By expressing the field in terms of reflection and transmission properties of the layers, the effects of stratification are taken into account. Field measurements with vertical geophones have been carried out and a comparison is made with predictions from the theoretical model. The predicted vibrations show good agreement with the experimental response; both the computed and measured results clearly show the Doppler effect. Surface waves, generated by oscillating trains, can be observed at large distances from the track, even if the train speed is lower than the speed of the surface waves.