• Title/Summary/Keyword: railway ballast

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Evaluation of Dynamic Stability of Precast Floating Slab Track with Vehicle-Track Interaction Analysis (차량-궤도 상호작용 해석을 통한 사전 제작형 플로팅 슬래브 궤도의 동적 안정성 검토)

  • Jang, Dongdoo;Kim, Jin-Ho;Kwon, Se-Gon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.562-568
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    • 2017
  • A precast floating slab track with a 5m slab panel and installed with isolators is proposed to solve the noise and vibration problem at existing elevated railway stations. Thus, the construction can be carried out rapidly without interrupting the train operation. However, dynamic instability problems may be caused by repeated discontinuities in track due to the short slab panel length and excessive rail displacement due to the inherent operation mechanism of a floating system in reducing the vibration. Furthermore, the difference of the supporting stiffness at the transition between the floating track and ballast track may raise problems. In this study, the assessment factors to evaluate the dynamic stability of the precast floating slab track are presented and assessed with the vehicle-track interaction analysis. Through the analysis, all values relevant to the stability at the floating track section are found to be acceptable, and the slab panels at the transition section are designed to satisfy the stability.

Estimation Method of Resilience Pads Spring Stiffness for Sleeper Floating Tracks based on Track Vibration (궤도 진동기반의 침목플로팅궤도 침목방진패드 스프링강성 추정 기법 연구)

  • Jung-Youl Choi;Sang-Wook Park;Jee-Seung Chung
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.1057-1063
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    • 2023
  • The urban railway sleeper floating track, the subject of this study, is an anti-vibration track to reduce vibration transmitted to the structure. currently, the replacement cycle of resilience pad for sleeper floating tracks is set and operated based on load. however, most previous studies were conducted on load-based structural safety aspects, such as fatigue life evaluation of sleeper anti-vibration pads and increase in track impact coefficient and track support stiffness due to increase in spring stiffness. therefore, in this study, we measure the vibration acceleration of the ballast for each analysis section and use the results of 7 million fatigue tests to calculate the spring stiffness of the resilience pad for each section. the spring stiffness of the resilience pad calculated for each section was set as the analysis data and the concrete vibration acceleration was derived analytically. the adequacy of analysis modeling was verified as the analyzed concrete bed vibration acceleration for each section was within the field-measured concrete bed vibration acceleration range. using the vibration acceleration curve according to the derived spring stiffness change, the spring stiffness of the resilience pad is estimated from the measured vibration acceleration. therefore, we would like to present a technique that can estimate the spring stiffness of resilience pad of a running track using the vibration acceleration of the measured concrete bed.