چكيده به لاتين
Abstract:
Identification of load transfer mechanism between superstructure and substructure of ballasted railway tracks plays an important role in railway track safety and performance. This issue is impacted by many factors that one of them is the quality of ballast material. Nowadays, utilization of steel slag ballast as an appropriate material instead of traditional stone ballast has been discussed. In this regard, one of the engineering concerns may be the differences between steel slag ballast and traditional stone ballast vertical load distribution mechanism. For this reason, the behavior of both kind of ballasts has been compared under vertical load using a fifty meters test track which was implemented by both kind of ballast materials. In this test track, the rail support modulus and the contact pressure of sleeper and ballast was studied by field tests. In order to determine the rail support modulus the Talbot method was used. So the track was loaded by both light and heavy 6 axles wagons with 300 and 1350 kN in weight, respectively. On the other hand, the special sleeper which equipped by load cells was used to measure the contact pressure of sleeper and ballast under mentioned heavy wagon in both kind of ballast materials. In overall, with the same track condition, the rail support modulus of steel slag ballast was obtained 1.64 times more than the lime stone ballast and the compressive contact pressure of sleeper and ballast in limestone ballast is almost 1.39 times greater than steel slag ballast.
Good match in comparison field investigation and result of track model indicate the validity of model. Calculation and test result shows using steel slag ballast instead of limestone ballast result in decreasing vertical displacement up to 40% in and decreasing stress on sub grade up to 42%.
Keywords
Ballasted railway track, rail support modulus, sleeper contact pressure distribution, steel slag ballast, limestone ballast
