• 한국철도학회논문집
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• 제8권4호
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• pp.354-360
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• 2005

The railway track and the substructures constructed in the field test section of Kyongbu High Speed Line are the structures for HSL, for the first time designed and constructed by domestic technical group. It is very important to verify the local design criteria and specifications for these structures and also to assure the recordings for vibration or deflection produced on the essential parts of the structures. The study to verify the high-speed railway track performance and to ensure the run in safety on the track in curved section during the KTX run. Finally, the conclusion are drawn as follows. The measuring values of the deflection effort of the rail and displacement for verifying the track performance in the field test section of Kyoungbu HSL satisfy the criteria of the foreign countries (Japan and Germany). The measured value for the wheel load and the presumed value show the consistent tendency. The wheel loads of the exterior and interior of the rails at the speed superior to 300km/h are measured same. Finally, the comparison between the theoretical value presented during the verification of the derailment to evaluate the safety of the train run at the time of the detailed design of the track and the measured value in the field shows that the correct design of track structure was applied.

• 한국측량학회지
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• 제22권4호
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• pp.391-400
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• 2004

철도 곡선부는 열차 운행속도에 중요한 영향을 미친다. 이 곡선부에서 완화곡선 길이는 곡선구간의 선형 적합성을 평가하는데 주요 요인 중 하나가 되며, 이 값은 주행속도와 캔트값에 의해 결정 되어진다. 본 연구에서는 장항선을 대상으로 완화곡선 길이를 확보하기 위한 평가를 실시한 결과 곡선구간의 약 2/3이 연장에 필요한 구간으로 밝혀졌으며, 완화곡선 연장방법을 적용함에 있어 곡선중점의 변경은 없고 곡선반경을 변화시켜 연장하는 방법이 선로중심선에서의 최대 이동량 및 곡선반경 편차를 최소화시킬 수 있으며, 또한 전면적인 선형개량이 어려울 경우 선형 적합성 및 속도향상에 효과적일 것이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1676-1682
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• 2008

The vertical curve of railway is installed in changing point where the gradient is more than a certain degree to ensure safe operation of train and comfort of passengers. As a result of CAD work with 3D coordination by using the existing equation, it was found that the simple equation about vertical curve installation suggested in the surveying engineering or railway regulations did not reflect theoretical curvature of circular curve in a case of steep grade and large vertical radius. In this study, for derive precision equation and transition curve about vertical curve, gradient parameters, equation of circles and transition curve equation were used, and it was verified by CAD that the derived equation is exactly satisfied with parameters of geometrical circular and transition curve. This equation could be used to provide more smoothing operation of train and comfort of passengers on vertical curves, especially in case that railway requires precision vertical alignment of track such as super high-speed railway, LRT or Maglev system.

• 한국소음진동공학회논문집
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• 제23권3호
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• pp.199-208
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• 2013

So far today, there is a speed limit by the radius of curve based on operation regulation in domestic railway, however a study for the maximum running speed at the curved section without any derailment would be necessary. The two major factors related to the running safety of railway vehicle are classified as the railway vehicle condition and the track condition. In terms of the rail inclination among many other factors, the determination of rail inclination within the possible limit is necessary for the geometrical structure of the optimum track. The disregard of the geometrical parameter related to the rail inclination may cause a serious problem to the running safety of railway vehicle. This study is focusing on the analyzing of running safety regard to the change of rail inclination among the many other parameters to improve derailment safety, so that there is an affection analysis of the running safety regard to the change of rail inclination in the ideal and geometric track condition. Also There is an affection analysis of the running safety regard to the simultaneous change of rail inclination and the running speed at the curved section. According to analysis results of running safety, In case that the left and right rail inclination are 1/40, the running safety of this condition defined than other conditions. Also, the rail inclination of conventional lines is 1/40, Therefore, the railway vehicle passing through curve is safe when the railway vehicle runs in conventional lines.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.948-954
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• 2004

이 연구의 목적은 호남선과 경부선의 기존선 전철화 선로의 곡선부에서 G7 개발차량과 KTX 차량의 속도를 증가해서 주행했을 경우 궤도구조의 성능평가와 주행안전성를 측정 분석한 것이다. 구조안전성과 주행안정성 평가를 위해서 측정기준으로 정립하였으며 계측망도를 구성하여 현장 계측을 수행하였다. 윤중, 횡압과 레일수직, 수평변위, 침목수직변위, 레일응력을 측정하였으며 이 결과를 토대로 궤도구조의 부담력과 열차 주행안정성을 평가하였다.

• Nuclear Engineering and Technology
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• 제38권4호
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• pp.353-358
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• 2006

Alpha track analysis for the determination of the trace amount of alpha emitting nuclides in a very small particle was performed as an efficient and powerful technique during safeguard inspection. Metal particles with well-defined spherical shape, size and isotopic compositions as a reference material were used to correlate the number of tracks or track diameter with an isotopic composition eventually to identify the uranium enrichment in the environmental swipe samples. Slopes in the number of tracks versus the exposure time curve provide a simple insight into the uranium enrichment of an unknown particle. Low enriched uranium metal particles result in slopes still steeper than the depleted or natural uranium metal particles. In addition, a linear relationship between track diameter and particle size Is thought to be a useful first stage analytical tool as an efficient and convenient inspection guide. The significance of the simple linear model was also judged using the usual statistical tests.

• Steel and Composite Structures
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• 제32권4호
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• pp.467-478
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• 2019

Running safety and ride comfort of high speed railway largely depend on the track geometry that is dependent on the bridge deformation. This study presents a theoretical study on mapping the bridge vertical deformations to the change of track geometry. Analytical formulae are derived through the theoretical analysis to quantify the track geometry change, and validated against the finite element analysis and experimental data. Based on the theoretical formulae, parametric studies are conducted to evaluate the effects of key parameters on the track geometry of a high speed railway. The results show that the derived formulae provide reasonable prediction of the track geometry change under various bridge vertical deformations. The rail deflection increases with the magnitude of bridge pier settlement and vertical girder fault. Increasing the stiffness of the fasteners or mortar layer tends to cause a steep rail deformation curve, which is undesired for the running safety and ride comfort of high-speed railway.

• Computers and Concrete
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• 제33권4호
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• pp.373-384
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• 2024

In this study, a novel mountain train system was developed that can run along a steep gradient of 180 ‰ and sharp curve with a minimum radius of 10 m. For this novel mountain train, an embedded precast concrete rack rail track was implemented to share the track with an automobile road and increase constructability in mountainous regions. The embedded rack rail track is connected to a hydraulically stabilized base (HSB) layer with shear anchors, which must have sufficient longitudinal resistance because they bear most of the traction forces originated from the rack rail and longitudinal loads owing to the steep gradient. In addition, the damage to the shear anchor parts, including the surrounding concrete, must be strictly limited under the service load because the maintenance of shear anchors inside the track is extremely difficult after installation. In this study, the focus was made on the shear anchor behavior and design an embedded rack rail track, considering the serviceability and ultimate limit states. Accordingly, the design loads for mountain trains were established, and the serviceability criteria of the anchor were proposed. Subsequently, the resistance and damage of the shear anchors were evaluated and analyzed based on the results of several finite element analyses. Finally, the design method of the shear anchors for the embedded rack rail track was established and verified.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.309-314
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• 2003

A vertical curve should be installed in straight section. In case, it be installed on horizontal curved section, safety factor go down. In this study, it is calculated that the deficiency of cant about vertical curve radius on horizontal curved section. The result of this study will be used on planning the tack layout of railroad and design the track construction.

• Structural Engineering and Mechanics
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• 제74권5호
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• pp.589-600
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• 2020

The bonding interface of the concrete slab track and cement-asphalt mortar layer plays an important role in transferring load and restraining the track slab's deformation for slab track structures without concrete bollards in high-speed railway. However, the interfacial bond-slip behavior is seldom considered in the structural analysis; no credible constitutive model has been presented until now. Elaborating the field tests of concrete to cement-asphalt mortar interface subjected to longitudinal and transverse shear loads, this paper revealed its bond capacity and failure characteristics. Interfacial fractures all happen on the contact surface of the concrete track slab and mortar-layer in the experiments. Aiming at this failure mechanism, an interfacial mechanical model that employed the bilinear local bond-slip law was established. Then, the interfacial shear stresses of different loading stages and the load-displacement response were derived. By ensuring that the theoretical load-displacement curve is consistent with the experiment result, an interfacial bond-slip constitutive model including its the corresponding parameters was proposed in this paper. Additionally, a finite element model was used to validate this constitutive model further. The constitutive model presented in this paper can be used to describe the real interfacial bonding effect of slab track structures with similar materials under shear loads.