Abstract

In this paper, the use of recycled tire-derived aggregates (TDA) mixed with ballast material is evaluated in order to reduce the train-induced ground-borne vibrations. For this purpose, a series of field vibration measurements has been carried out at an executed pilot track. The prepared ballast layer was mixed with different percentages of TDA in three sections. Moreover, another test section with pure ballast is considered as a reference. The vibrations generated by a motor-powered draisine at two different speeds are then recorded. Records of vibration data are provided using four seismometers placed once longitudinally and once transversely beside different sections. The outputs are then processed in both velocity–time and velocity–frequency domains. To verify the vibration mitigation performance of TDA in real operation conditions, field measurements under the passage of two planned passenger and freight trains are finally arranged. Results show that the best TDA mixture ratio, i.e., 10% by weight, can reduce the transmitted vibrations up to 12 dB for frequencies above 31.5 Hz. According to the obtained efficiency and the very low cost of the recycled materials, this solution can be considered as a competitive vibration countermeasure.

Highlights

  • Ground-borne vibrations induced by train traffic have undesirable impacts on adjacent sensitive structures and may cause disturbance of the surrounding occupants

  • Apart from the RMS velocities, which were expressed in mm/s, the amount of vibration reduction under the use of tire-derived aggregates (TDA) can be interpreted in the frequency domain by using insertion loss (IL) index [7]: VdB 1⁄4 20 Â lg where VdB is the velocity loss level in decibel and Vb and Va denote root mean square of vibration velocities before and after using TDA

  • This study has presented and evaluated the potential of recycled TDA mixed with ballast layer for ground-borne vibration reduction of railway lines

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Summary

Introduction

Ground-borne vibrations induced by train traffic have undesirable impacts on adjacent sensitive structures and may cause disturbance of the surrounding occupants. Esmaeili and Rezaei [11] conducted a series of impulse–response (IR) tests on a prototype of a ballasted track with TDA sub-ballast layer Besides the vibration mitigation methods mentioned, some recent studies [12–19] introduce a new approach of mixing the ballast material with TDA to increase the track resiliency, improve the damping properties, and decrease the breakage and wear of ballast particles Based on these researches, the effects of TDA on various aspects of ballast layer including particles degradation, static and dynamic performances, and damping properties have been investigated both experimentally and numerically under normal circumstances and sand-fouled conditions. As a reliable reference, the vertical vibration responses of TDA are evaluated during the passage of two passenger and freight trains and the end conclusions about the place of TDA mixed with ballast in vibration reduction measures are presented

Test track condition
Instrumentation plan
Ballast and TDA properties
Excitation method
Draisine results in the time domain
Draisine results in the frequency domain
Findings
TDA–ballast rank in vibration mitigation
Conclusions
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