چكيده به لاتين
Due to the increasing development of continuous welded rail, the concept of longitudinal resistance of ballasted railway tracks and its direct effect on track buckling is considered as important and challenging in the railway. The loads that are imposed on tracks consist of vertical, lateral, and longitudinal forces in which the longitudinal force is required to cause stress on rails. The track structure should have the ability to show enough resistance against all types of forces such as vertical, lateral, longitudinal, and torsional forces, which are caused due to traffic and temperature changes, and it must not be subjected to buckling, movements more than standard values, or any other damages which can disrupt the operation of track. This thesis investigates the effect of vertical and lateral loads on the longitudinal resistance of ballasted tracks. According to the studies in this area, the experimental and numerical research has not been carried out with the load equivalent to the freight load and the presence of vertical, lateral, and longitudinal loads simultaneously. In order to do so, the loading frame in the superstructure laboratory of railway engineering department of Iran university of science and technology was used, and after completion of the required equipment, the specified tests were carried out. In continuation, numerical modeling has been developed using Abaqus software and has been used to validate the experimental results. It has been shown that by applying vertical load to the track, the longitudinal resistance of the track increases sharply. Thus, by applying the vertical loads 10, 20 and 30 tons to the track, the longitudinal resistance increases by 105.75 %, 174.1 % and 197.06 %, respectively. Also, by applying the lateral load, the longitudinal resistance of the track is reduced as low as 9.9 % in the absence of the vertical load. After increasing the vertical load to the 30 tons limit, the reduction of longitudinal resistance drops down to 5.15 %.
