چكيده به لاتين
Abstract:
In this thesis, the effect of different thicknesses of the deconstructed tire under sleeper pad (DT-USP) and different unconfined compressive strength (UCS) values of mother rocks of three different ballast aggregates on ballast deterioration are investigated by deconstructing of USPs and manufacturing the DT-USP. For this purpose, first, the mechanical properties of the DT-USPs, including static and dynamic bedding modulus according to DIN 45673-6, were extracted. In the next step, the cyclic behavior of the three ballast types of Shahriar, Anjilavand and Kouhin mines with 159, 216 and 285 MPa UCS values of intact ballast rock, respectively, with grading used in the Australian TfNSW rail network according to AS 2758.7-1996 with ballast box test With and without DT-USPs in three thicknesses of 7, 10 and 13 mm under 200,000 cycles have been evaluated and compared. The loading frequency in the ballast box was 3 Hz and the maximum load was 43 KN such as the axle load of 8.6 tonnes. Experimental results were extracted as ballast breakage index (BBI), settlement, stiffness and damping ratio to investigate the effect of ballast parameters and DT-USPs. The results indicated that with increasing the thickness of these pads, from sample without pad to sample with pad thickness of 13 mm with Shahriar ballast type settlement decreased by 24.4%, BBI reduced by 7.9%, stiffness decreased by 4.13% and damping ratio boosted by. 199.2% , and with Anjilavand ballast type settlement decreased by 18.2%, BBI reduced by 7.2%, stiffness decreased by 886.7% and damping ratio increased by 179.8%, and finally with Kouhin ballast type settlement decreased by 11.4%, BBI reduced by 8%, stiffness decreased by 341.9% and damping boosted by 91.9%. Also, based on the results, DT-USP with 11 mm thickness was selected as the optimal DT-USP.
Keywords: Elastic Elements, Under Sleeper Pad, Ballast Box Test, End-of-Life Tires, Ballast Deterioration
