The Dynamics of Railway Track and Subgrade with Respect to Deteriorated Sleeper Support

Full scale laboratory experiments are performed in order to investigate the dynamic behavior of a ballasted track segment and its constituents. Since voids are often observed between sleepers and the underlying ballast, special emphasis is laid on investigations of partially unsupported sleepers. Detailed information on the dynamic displacement field is obtained by the holographic interferometry which is used beside conventional accelerometers to record the oscillations. It is shown that deviations from optimal coupling to the subgrade result in significant changes of the dynamic behavior. The results of the laboratory experiments are in good agreement with in-situ measurements. Elementary configurations are also corresponding well with numerical results.