Performance of Shred Tires Mixed with Railway Subgrade in Reduction of Train Induced Vibrations

In this study, the performance of shred tire mixed with railway subgrade was evaluated for reducing the environmental vibrations caused by trains’ passage. Since incorporating the shred tire seeds in soil affected on its shear strength and deformability parameters, so the first stage of the study was allocated to conducting a series of laboratory tests such as the unconfined compression, CBR and cyclic plate loading tests on the base material of GW-GC in combination of tire derived aggregates with particle size ranged from 0.475 to aggregation 2.5 cm in four various percentages of 0, 5, 10 and 15. Moreover, the cyclic plate loading tests were accomplished to determine the mixture elasticity modulus in the second loading cycle as Ev2. By using the obtained values of shear strength as well as deformability parameters in the lab, a 2D numerical model of ballasted track was established under step train loads corresponding to a passenger bogie. The numerical results showed that the vertical vibration velocity at the ballast shoulder decreased up to 44.56 percent while this value reached to 44 percent for a point with 5 m distance from track shoulder with increasing in the shred tire percentages from 5 to 15 percent. As a practical result, an equation was proposed to show the relation between shred tire percentages and values of environmental vibrations.