Lateral Cyclic Deformation Characteristics of Railroad Ballast

Tatsuya ISHIKAWA, Masao UCHIDA
In the structural designing of ballasted track, the method to control the irregularity of longitudinal level has been used conventionally. On the other hand, the assurance of passenger's comfort has recently come to be recognized to be increasingly critical with increasing train speed on curves. So considering the restraint of the irregularity of alignment essential, the conception of allowable lateral displacement has been introduced into the design of ballasted track. As the lateral deformation of track is dominated by the deformation characteristics of ballast, analyzing the deformation of ballast under train passages quantitatively is needed for the sake of passenger's comfort. In order to elucidate the mechanism of lateral track deterioraiton, we study the lateral cyclic deformation characteristics of railroad ballast, which has important influence on the phenomena such as impulsive or progressive growth of irregularity of alignment, in terms of practical use. As a result, we propose a worthy method to estimate lateral deformation of railroad ballast.