چكيده به لاتين
Abstract
Abrupt track vertical stiffness variations along railway tracks can lead to increased dynamic loads, asymmetric deformations, damaged track components, and consequently, increased maintenance costs. The junction of slab track and ballasted track is one of the existing areas where vertical track stiffness can suddenly change, therefore requiring a transition zone that smoothes the track stiffness change. One of the methods for constructing the transition zone at the junction of slab and ballasted tracks is to install auxiliary rails along the transition zone. Besides, an innovative method that developed as a transition zone in this study is using a combination of approach slab and additional rails.
At first, the dynamic behavior of this type of transition zone using field tests evaluated in this study. Hence, in Tehran-Karaj railway line, two types of transition zone were constructed: one including merely the approach slab and another one considering additional rails and approach slab. Then, conducting some field tests, the dynamic behavior of the track in these two types of transition zone was examined.
Furthermore, the dynamic behavior of the mentioned transition zones evaluated by a train-track interaction model. For this purpose, a 3D model of the railway track was made, representing the slab track, the transition zone, and the ballasted track. Then, the modeling results were validated by the results of field tests. Afterwards, in order to study the dynamic behavior of the transition zones with auxiliary rails and combined additional rails and approach slab, different sensitive analyses, such as vehicle speed, vehicle load, number of auxiliary rails and railpad stiffness, were performed with the model.
Keywords
Railway track, transition zone of slab track to ballasted track, auxiliary rails, approach slab, field test, 3D train-track interaction model.
