Spatial distributions of railway-generated ground vibrations at and around sleeper passage frequencies

In this paper, spatial distributions of ground vibrations generated by railway trains travelling at conventional speeds on straight tracks are investigated theoretically. The main attention is being paid to calculations of spatial distributions of ground vibrations generated by a single axle load at and around sleeper passage frequencies that are defined by train speeds and sleeper periodicity. It is demonstrated that, at sleeper passage frequencies, generated ground vibrations represent plane waves propagating symmetrically away from the track in the normal directions to it. At frequency components that are slightly above or below sleeper passage frequencies, generated ground vibrations still remain plane waves, but they are now propagating at certain angles in respect of the normal directions to the track.