• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.8-16
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• 2018

This study examined the long-term behavior of a roadbed using high-speed railway concrete track and roadbed measurement data and evaluated the long-term performance of the track and roadbed. Recently, high-speed railway track type has been adopted as a concrete slab. On the other hand, the concrete track is vulnerable to roadbed settlement. In the case of gravel tracks, it is easy to restore the original state by maintenance even if the roadbed settles. On the other hand, in the case of the concrete track, if excessive settlement of the roadbed occurs, cracks are generated continuously on the slabs and sleepers, resulting in greatly reduced usability. For this reason, it is difficult to restore the original state only by partial maintenance. In this paper, a long-term performance evaluation was carried out on a concrete track during operation by monitoring the measurement data of sensors buried from the beginning of construction for approximately 3 years after the high-speed railway opened. Performance evaluation methods include a performance evaluation of track/roadbed when the train passes, long-term track and roadbed performance evaluation, analysis of the track/roadbed effect on long-term settlement and analysis of the factors influencing long-term settlement. The trail response of KTX-Sancheon was greatest in the track/roadbed performance evaluation by train. The results of the long-term track and roadbed performance evaluation were measured within the standard values. The track and roadbed performance impact assessment with long-term settlement was strongly related to TCL settlement. The influences of the water content and groundwater level were verified by analyzing the external factors of long-term settlement. Through such a method, the stability of a track/roadbed can be secured.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.715-722
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• 2016

Most of the domestic railroad tracks are ballast track and repetitive maintenance is required in this track. Therefore, it is necessary to optimize maintenance process for maintenance cost reduction and more effective maintenance. For this, it is important to develop a reasonable settlement progressive model of ballast layer. However, the behavior of ballast is different to that of soils, since ballast is composed of large coarse gravel. Thus, in this study, we carried out numerical analysis by using the discrete element method (PFC 2D) for better understanding of ballast settlement and development of reasonable settlement progressive model. And, we evaluated the settlement of ballast according to particles shape, porosity and loading conditions.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.470-473
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• 2006

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.565-573
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• 2009

Displacement of the bridge and additional rail stress due to interaction between track and bridge should be limited to the design criteria. Interaction analysis was conducted to investigate the displacement and additional rail stress on CWR in high speed railway bridge. Particularly, various parameters affecting interaction phenomena were taken into account in the analysis to enhance an applicability. These parameters included configuration of structure, stiffness of deck and support, steel/concrete bridge, ballast/concrete track and FM/MFM type etc. The results were presented in the form of the design chart which could be useful in preliminary design of the bridge.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.195-203
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• 2016

Concrete slab track was applied to the Gyeoungbu High Speed Railroad step 2 and the Honam High Speed Railroad. Concrete slab track incurs higher construction cost and lower maintenance cost than existing gravel track. For these reasons, the use of concrete slab track has increased in Korea. The biggest problem in the use of concrete slab track is repairing damage from settlement that can occur while trains are in service. High speed railroad design standards require allowable residual settlement of concrete slab track of less than 25mm. In order to satisfy the requirement of long term stability of concrete slab track, it is necessary to manage the secondary compression settlement within the allowable residual settlement. This study is to evaluate the secondary compression settlement with the variation of the secondary compression index, thickness of soft ground, and concrete slab track life. Statistical analysis is performed to determine the probability of distribution of areas where serious problems will be caused after the concrete slab track is constructed.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1126-1131
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• 2007

In 1st Phase Kyeong-Bu High-Speed Line, to lessen the impact in the transition zone between concrete slab track(in tunnel) and ballasted track(on embankment), the ballast bonding method has been adopted. However, in this area, in the beginning of the operation, unsupported sleepers are found, and the track deterioration and damage of concrete sleepers have occurred. In this paper, the status and causes of unsupported sleepers are discussed and several repair measures are proposed.

• Journal of the Korean Society for Railway
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• v.4 no.4
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• pp.8-14
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• 2001

레일의 이음매부는 상시 차륜에 의한 충격ㆍ진동이 크기 때문에 이음판ㆍ볼트의 이완, 레일 단부의 변형ㆍ손상, 도상 자갈의 파괴ㆍ세립화의 발생 등 궤도 관리상의 최약점 개소로 되어 있다. 지금까지 이와 같은 이음매부를 줄이기 위하여 수송밀도가 높은 주요 간선에 대하여 용접에 의한 레일의 장대화가 진행되고 있으며, 또한 구조물 주변의 보수가 곤란한 개소 및 도시 구간에서의 소음ㆍ진동 대책뿐만 아니라 궤도 보수 작업의 경감과 열차의 고속화ㆍ승차감의 개선 등에 레일 용접이 크게 공헌하고 있다. (중략)

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.55-64
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• 2009

Recently, concrete track is replacing ballast track for efficient and economic maintenance of track. It considerably offer less maintenance, a longer service life and reduced life-cycle costs. With the aim of achieving high-quality track construction work, of developing tools for quality assurance in new construction and for later technical inspection of material condition, a quality strategy has to be developed. For these purpose, NDT which is using the seismic wave has carried out in situ studies in the test construction section. The used NDT are SASW test, impact echo test and continuous impact echo test. The test is performed 5,353 times on 49 pre-cast concrete track panels to verify the stiffness structure and grouting efficiency of the track structure. To conclude, because of the non-homogeneous characteristic of concrete material. it is restricted to apply the elastic wave test at some aspect. However it is possible to acquisite a sufficient reliability about structural stiffness and grouting efficiency of concrete track.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.286-297
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• 2013

In this paper we evaluated dynamic stability, considering the effects of modeling and analysis methods on moving load analysis, for which a sophisticated 3 dimensional model of a PSC-I type girder bridge was used. For this purpose, we suggested a reasonable modeling method and the physical properties of the concrete and ballasted track system involved. We also analyzed the response characteristics according to: 1) the type of track system; 2) whether or not the track was modeled; 3) whether or not the distance between the girder center and the bearing were considered; 4) the analysis method (i.e., direct integral and modal analysis); 5) whether or not the frequency was filtered.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4532-4541
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• 2013

With speed up of railway, the demand for safety of the railroad transportation is on the increase in Korea's conventional railways. In additions, freight trains with heavier axle load are required to run conventional railways. In order to solve these requirements, the increase of rail weight and the application of long rail system have been underway in conventional railways. However, the research on ties that is absolutely influencing the track stiffness in ballasted tracks has not been much progress. In this paper, the new H-typed tie is developed to increase the track stiffness and reduce the track irregularity. And from the structural analysis by FE program, the intial design drawing of the new H-typed tie is proposed.