چكيده به لاتين
The present thesis investigates the railway ballasted track longitudinal resistance with a focuing on determining the superstructure components proportion of it. Understanding the role and contribution of ballasted railway superstructure components is very importance due to the variety and multiplicity of forces applying to the railway track and it's unpredictable behavior. Investigations at the my MSc's seminar indicate that there is not such research work has been carried out to investigate the effect of ballasted railway superstructure components, such as the amount of pre-compression of fastening system and the effect of the presence or absence of a under rail-pad, on the longitudinal resistance and stiffness of the ballasted track in the our country and worldwide.
Accourding to the novelty of the selected subject and the existing laboratory conditions at the railway superstructre laboratory in School of Railway Engineering , it was decided to use the existing track loading frame in the laboratory. This loading frame, consisting of two half-buried columns at one end of the track panel rails which was used as a supports for the longitudinal loading hydraulic jacks for longitudinal loading of track panel. The force applied to the track panel rails and it's displacemnt was measured by two loadcells attached to the rails and six LVDTs attached to the track panel respectively, and all datas recorded through the computer system which all the sensors used during the test, were connected.
After providing the equipment needed to build the track panel used in the experiments, such as the vossloh sleepers, vossloh fastener pack, under rail-pads and finally the replacement of the exsiting ballast with broken granite ballast, a comprehensive schedule of research experiments was arranged to the track panel has the least change, especially in the ballast layer, and the fastest speed to reduce the time spent.
After successfully performing all the scheduled experiments by repeating serveral times, the results were obtained that at a pre-compression force of 100 N.m applied to the fastening system, the fastening system contribution is 35% and 14% decreasing with and without using under rail-pads respectively, with the number of sleepers connected to the track panel rails increasing from one to five. This reduction the fastening system contribution for a pre-compression force of 80 N.m applied to the fastening system, is 26% and 18% with and without using under rail-pads respectively and for 60N.m pre-compression force applied to fastening system, this contribution is 16% and 6% with and without using under rail-pads respectively.
The sleeper contibution of track panel creepage is the same as the relative contibution of the track panel creep, except that the contribution amount trend is incremental.Track panel longitudinal stiffness by varying the number of connected sleepers to the track panel rails from one to five sleeper for the pre-compression force of 100 N.m with and without the under rail-pads inscresed 9 and 13 kN / mm, respectively, at the pre-compression force of 80 N.m compression with and without the under rail-pads is respectively 11 and 12 kN / mm and for pre-compression force of 60 N.m with and without the under rail-pads is 9 and 12.5 kN respectively. The ultimate longitudinal resistance of the track panel also increased by increasing the number of sleepers from one to five, for pre-compression force of 100 N.m in the case of with and without under rail-pads 38 and 32 kN, respectively, at pre-compression force of 80 N.m with and without under rail-pads 39 and 25 kN, respectively, and for the pre-compression force of 60 N.m with and without the under rail-pads 31 and 17 kN, respectively.
