Modelling railway ballasted track settlement in vehicle-track interaction analysis

The geometry of a ballasted railway gradually deteriorates with trafficking, mainly as result the plastic settlement track-bed (ballast and sub-base). rate amount depend on number factors, for various reasons are difficult to predict or estimate analytically. As result, empirical equations estimating development track train passage have been proposed. A review these shows that they (i) do not reproduce form vs load cycles relationships usually seen in field; (ii) reflect current knowledge behaviour soil subgrades cyclic loading; (iii) often critically dependent curve fitting parameters used, which turn circumstances calibration data were obtained. To address shortcomings, this paper develops semi-analytical approach, based known granular materials under loading, calculation settlements trackbed passage. model is then combined suitable vehicle-track interaction analysis calculate rates permanent different initial stiffnesses, vehicle types speeds. shown be able recursive effects, deterioration causes an increased variation dynamic load, feeds back into further geometry. new represents significant improvement equations, it observed aspects basis soils ballast loading.