It has been confirmed that track irregularity gradually returns to its original shape after ballast tamping on ballasted track even under the same track and support structure conditions. However, the details of this mechanism are not yet clear. Therefore, we surveyed an actual situation using track inspection data for this phenomenon. In addition, we performed tests with small-model, discontinuum analysis for ballast density after ballast tamping and cyclic loading tests, to reveal the mechanism of reversion in settlement after and before ballast tamping.
NAKAMURA et al. (Sun,) studied this question.