• Proceedings of the KSR Conference
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• 2001.05a
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• pp.281-288
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• 2001

In order to evaluate the effect of impact load at support stiffness transition area, the field estimations are performed at the transition zone between earthwork and bridge on test operation of KTX. Due to differential settlement caused by the variations of track support stiffness, large impact forces are investigated. However, the measured values such as wheel load, rail stress, displacement and acceleration in the transition area shows that the stiffness changes in the transition area are not abrupt, and the stiffness in the infra track structure varies continuously. In this experimental study, the parameters influencing safety of transition area are not governed by partial or local stiffness because cumulative passing loads are not sufficient on test operation of KTX.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.228-233
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• 2002

The transition between bridge or tunnel and plain track has different rail pressure and distributed stress on formation. This paper shows distribution of rail pressure on transition at which spring stiffness are changed. By this study, it is revealed that the changing into relatively high stiffness causes increased rail pressure visibly and draw up dynamic track force. A medium stiffness structure and reinforced rail could be effective for reducing track force on the transition.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.351-357
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• 2007

The transition zone between railway embankment and structures, or different track types is known to be an area in which problems often arise and where extra care needs to be taken with maintenance. Differences in track stiffness have dynamic effects and these increase the force in the track and the extent of deformation. In this study, the criteria for the change ratio of track stiffness along transition area, and proper transition length are presented through train/track interaction analyses. Those are derived on the basis of permissible limitations of train and track performances such as rail stress, uplift force of fastener, reduction of dynamic wheel force, and acceleration of car body. A feasible method of evaluation of track stiffness which is necessary when a designer reviews whether the criteria are satisfied or not is also presented.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.726-733
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• 2005

It is very important to pay careful attention to construction of earthwork/tunnel transition zone for railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. In this study, performance of transition zone was investigated through the field tests. The wheel loads and sleeper settlement were measured after installing field testing sections.

• Journal of the Korean GEO-environmental Society
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• v.22 no.4
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• pp.5-13
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• 2021

The transition is the zone where support stiffness suddenly increases in the railway industry. If the support stiffness increases, differential settlement will occur at the transition due to difference of stiffness, and the differential settlement causes problems for the train running safety and the roadbed that supports the track. In particular, a study on differential settlement at bridge-earthwork transition was only conducted to considering railway load in most cases. However, these studies have not taken account of earthquake despite earthquake has been occurred frequently in the recent, and it is necessary to consider earthquake. Therefore, in this study numerical analysis has been performed by changing the inclination of approach block, which determines the shape of the transition, and earthwork in order to verify the effect of the shape of the transition on the dynamic behavior at the bridge-earthwork transition. The result shows that the dynamic behavior at the bridge-earthwork transition was affected by the shape of transition.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.647-655
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• 2016

The construction of high speed railways and improvement projects of for conventional railways require straight railway lines of railway, which leads to an increase of bridge and tunnel construction. Transition zones in railways means that the track support stiffness is variedvaries in over short ranges. Sspecial attention is required in theose transition zones since because instability of train running in train and irregularities of track irregularities are can frequently occurred. Typical transition zones are between bridges and earthworks and between tunnels and earthworks. On In a transition zone, a bridge abutment transition zone has many problems in with various causes. In this paper, fundamental problems of bridge abutment transition zones is are analyzed to enhance the understanding about of bridge abutment transition zones. Suggestions for improving problems in the transition zones are proposed.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.129-134
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• 2003

It is very important to pay careful attention to construction of bridge/earthwork transition zone for high-speed railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. An abrupt change of stiffness across two adjacent track portions cause irregular settlement of roadbed, track irregularity, lack of girder bending moment and reduction of lateral resistance. Especially on high-speed railway, track irregularity of transition zone cause sincere effect to track stability and train safety. And so continuous maintenance is needed. To verify this effect and to improve transiton zone capacity, In situ test, track irregularity and train acceleration test were performed on high-speed railway bridge/earthwork Transiton Zone.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1279-1286
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• 2006

It is very important to pay careful attention to construction of earthwork/tunnel transition zone for railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. In this study, performance of transition zone was investigated through the field tests. The wheel loads and sleeper settlement were measured after installing field testing sections.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1056-1061
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• 2007

Railroad roadbed was consisted into structure types that earthwork, tunnel, bridge and joint sections. Joint section was affected a large factor confidence and safety of the train running by stiffness transition zone that track substructure stiffness change section as like between tunnel and earthwork from ballast track to concrete track. These problems are the results of increased dynamic wheel loads, which also lead to wear and tear on vehicle components and contribute to poor ride quality. The study presented in this paper was conducted on model test by using Wheel Moving Loading System.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.256-263
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• 2002

This paper deal with optimal design of reinforced track as a track reinforcing method for transition area of track support stiffness in transition area between bridge and earthwork. When vehicle passes through transition area, dynamic properties between vehicle and track are studied by the analysis of vehicle-train interaction for the each case when reinforced tracks are used or not. furthermore, optimum decision of type and length of track are made based on the performance adapting variable parameters : support stiffness of track for bridge and earthwork, heading direction of vehicle and type and length of track.