• International Journal of Railway
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• 제7권1호
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• pp.8-15
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• 2014

Recently, in the total railroad construction field, concrete slab tracks have been adapted in place of ballast tracks. Because ballast tracks need frequent maintenance and are difficult to handle due to increasing maintenance costs, eventually concrete slab tracks were selected as an alternative. However, owing to the hydration heat reactions and temperature-affected shrinkage of the concrete, a variety of studies to solve maintenance problems related to concrete slab tracks are underway. This study analyzed characteristics of TQI values evaluating track irregularity, investigated the relationship between crack progress and TQI, and then evaluated the correlation between the two values. Through our analysis, we found that there is a need to supplement the problems of the current method and develop a track evaluation index which takes cracking into account. We also concluded that TQI is the main decision-making tool in track maintenance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.769-774
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• 2004

In this paper, the main factors affect on the longitudinal rail force are discussed. Considering rail-bridge interaction, analytical and experimental evaluation of track behavior has been achieved. It is concluded that the horizontal ballast strength, the expansion length of the bridge span, and the stiffness of the bridge sub-structure are the significant parameters affecting the stability of the continuous welded rail (CWR) track. And, it is suggested that the ballast resistance forces should be maintained to ensure the track stability during the service.

• 한국철도학회논문집
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• 제4권2호
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• pp.39-46
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• 2001

In this paper, train running test and lateral resistant force test are conducted before and after sprinkling the ballast stabilizer in order to investigate the dynamic behaviors and parameters of the railroad track. The measured results are used to confirm the effect of the stabilizer and to validate the numerical results. From this paper, it is known that the stabilizer used in this study has excellent effect on increasing the vertical rigidity and the lateral resistance, and some correction factors should be considered on masses and rigidities of the track components in order to calculate the vibration magnitude reasonably due to running train.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.558-564
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• 2006

When vehicles pass the connection between the bridge and earthwork, the difference of both sections' stiffness produces an increasing wheelload. As a consequence, it results in the excessive vibration of vehicles and the damage of bearing system. In general, steel plate girder railway bridges without ballast track have larger stiffness than the bridge with ballast, and produces larger impulse on the bridge superstructure. Thus, it is necessary to reduce the differences of both stiffness. This study presents parametric studies on the behavior of plate girder bridges and their tracks by means of various stiffnesses and the length of approach zone. The results of numerical study showed that the smaller the stiffness of both sides and the longer the length of approach zone, the variation of wheelload becomes smaller. Hence, it gives less burden into the plate girder bridges and their tracks. It is expected that the results of parametric study can be used as a preliminary data for the determination of economical length on the approach zone and the stiffness of both sides.

• Geomechanics and Engineering
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• 제5권3호
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• pp.263-281
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• 2013

Geotextiles and geogrids have been in use for several decades in variety of geo-structure applications including foundation of embankments, retaining walls, pavements. Geocells is one such variant in geosynthetic reinforcement of recent years, which provides a three dimensional confinement to the infill material. Although extensive research has been carried on geocell reinforced sand, clay and layered soil subgrades, limited research has been reported on the aggregates/ballast reinforced with geocells. This paper presents the behavior of a railway sleeper subjected to monotonic loading on geocell reinforced aggregates, of size ranging from 20 to 75 mm, overlying soft clay subgrades. Series of tests were conducted in a steel test tank of dimensions $700mm{\times}300mm{\times}700mm$. In addition to the laboratory model tests, numerical simulations were performed using a finite difference code to predict the behavior of geocell reinforced ballast. The results from numerical simulations were compared with the experimental data. The numerical and experimental results manifested the importance that the geocell reinforcement has a significant effect on the ballast behaviour. The results depicted that the stiffness of underlying soft clay subgrade has a significant influence on the behavior of the geocell-aggregate composite material in redistributing the loading system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 춘계학술대회 논문집
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• pp.415-422
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• 2006

• 한국철도학회논문집
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• 제8권3호
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• pp.228-234
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• 2005

Investigation on the dynamic behavior of railway bridges has not performed widely to date except high-speed railway bridges. In this study, 3-dimensional model is used for the finite element analysis of plate girder railway bridges. Train loads obtained through statistical approach of the measured true train loads are used. Numerical analysis is carried out about a 18m-span bridge. This result is compared with that of the experimental test of existing plate gilder railway bridge without ballast. The good agreement was obtained through the comparison. Judging from the analysis, resonant speed of diesel locomotive train is about 120km/h. However, the resonance for the other train is not found from the analysis.

• 한국철도학회논문집
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• 제18권6호
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• pp.578-585
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• 2015

궤도의 탄성 구성요소는 기술적 및 경제적으로 효율적인 철도 네트워크를 위해 궤도상부구조로 잘 통합될 수 있다. 탄성 레일패드는 곡선반경이 800m보다 큰 경우 부드러운 레일지점과 고속(160km/h 이상)을 제공한다. 높은 궤도저항성은 눈에 띄게 다짐주기를 연장시킨다. 침목패드의 꾸준히 증가된 점유율은 향상된 다짐주기와 연마주기를 제공하고, 좁은 곡선반경에서도 기술적인 철도구조물 그리고 고체음의 감소에 대한 대책을 제공하기 때문이다. 밸러스트 매트의 설치는 신설선 건설 또는 광범위한 혁신 조치의 차원에서 특히 방진 및 구조물 보호와 같은 좋은 효과를 준다. 다만, 적절한 설치에는 세심한 주의가 필요하다.

• 문화기술의 융합
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• 제9권4호
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• pp.537-542
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• 2023

최근 도심지 주변으로 집중되는 신축구조물 및 공동구 확장 등과 같은 인접굴착공사로 인해 운영중인 철도 구조물의 변형이 발생되고 있다. 그러나 대부분 구조물에 대한 구조검토 및 보수보강에 집중되고 있으며 궤도에 대한 검토는 부족한 실정이다. 특히 토공노반 상 자갈궤도의 경우 노반과 도상자갈이 강결된 구조가 아니므로, 미소한 수준의 변형으로도 도상자갈 이완현상이 발생할 수 있다. 이는 침목 지지조건이 불안정한 조건으로 유도될 수 있으므로 충분한 안전성을 확보해야한다. 또한 불안정한 지지조건으로 열차탈선의 위험이 매우 높은 궤도형식이다. 따라서 본 연구에서는 노반 변형에 따른 자갈궤도의 변형특성과 궤도지지성능의 상관관계를 실험 및 해석적으로 입증하고, 자갈궤도의 상태 및 궤도지지강성을 평가할 수 있는 평가기법을 제시하고자 한다.

• 대한토목학회논문집
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• 제28권3A호
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• pp.315-322
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• 2008

본 연구에서는 외부 후 긴장 보강 공법을 공용중인 무도상 철도 판형교 보강 방안으로서 적용 할 경우 긴장재 강성 및 도입 긴장력의 크기가 동적 거동 특성 변화에 미치는 영향을 실험 및 해석적으로 평가 하였다. 연구 결과 긴장재 강성에 의해 고유 진동수가 증가하나 긴장력 크기 증가에 의한 고유 진동수 감소에 의해 필요 긴장력 도입시 최종적으로 고유 진동수가 미소하게 감소하는 것으로 나타났으며, 외부 후 긴장력과 고유 진동수 변화 양상에 대한 명확한 관계 정립을 위한 추가적인 연구가 필요한 것으로 나타났다. 또한, 외부 후 긴장에 의해 동적 처짐, 동적 휨 응력 및 중력 방향 가속도가 감소하는 것으로 나타났다. 한편, 외부 후 긴장에 의하여 중력 방향 가속도의 70% 수준인 횡 방향 가속도가 최대 20% 정도 증가하는 것으로 나타나 이에 대한 추가적인 연구가 필요한 것으로 판단된다.