• Title, Summary, Keyword: Railway roadbed

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Grouting Performance for the Reinforcement of Operating Railway Roadbed (운영 중인 철도노반 보강을 위한 그라우팅 성능)

  • Jung, Hyuk Sang;Han, Jin Kyu;Moon, Joon Shik;Yoon, Hwan Hee
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.12
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    • pp.13-23
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    • 2017
  • This paper discusses about the reinforcement materials and construction method in order to cope with roadbed settlement in operating railway. In Korea, concrete tracks have been introduced to urban railways, high-speed railways, and general railways, but some recently constructed concrete tracks have experienced roadbed settlements. Reinforcement of the railway roadbed is urgent task for safe operation of railway, but it is difficult to reinforce the roadbed and there are no case history of reinforcing railway roadbed under an operating railroad track. Therefore, in this study, the target performance level for roadbed reinforcement was determined, and infiltration and solidity injection efficiency were investigated for selected reinforcement materials. As a result of the study, it was found that the generally used reinforcement materials and methods for geotechnical works need to be improved for applying in railway roadbed reinforcement.

A study on Development of Design Method for Reinforced Railway Roadbed by Geocell (지오셀로 보강된 철도노반의 설계기법 개발에 관한 연구)

  • 심재범;신민호;조삼덕;채영수
    • Proceedings of the KSR Conference
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    • pp.614-619
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    • 2002
  • Since 1980's in U.S.A and Japan, the studies on increasing the bearing capacity of railway roadbed using geocell have been conducted for repair and reinforcement of railways constructed on soft soils. In this study, the railway roadbed system reinforced with geocells has been analyzed and investigated results of the previous studies were conducted in Korea and other nations, And the method for estimating the railway roadbed thickness was developed based on the equivalent method using the multi-layer theory and the deformation modulus Ev.

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A Design Method of Reinforced Railway Roadbed by Geosynthetics (토목섬유로 보강된 철도노반의 설계기법)

  • 심재범;채영수
    • Proceedings of the KSR Conference
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    • pp.423-429
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    • 1999
  • The design method of Geosynthetics reinforced Railway Roadbed that was developed in Germany in 1997 is presently putting into practice. This method insists that Railway Roadbed Thickness has to be measured by Frost and Bearing Capacity The Maximum Value from the above two measurements is the necessary Railway Roadbed Thickness. This design method has many kinds of advantage in economic, constructive aspect, and environmentalism. Recently a few Korean experts actively have researched on this area, but their results are not enough for proper design method. Ⅰ hope more complete study on this area will be progressed.

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Static Behavior of Reinforced Railway Roadbed by Geotextile Bag (지오텍스타일 백으로 보강된 철도노반의 정적거동 분석)

  • Lee, Dong-Hyun;Shin, Eun-Chul
    • Journal of the Korean Society for Railway
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    • v.9 no.2
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    • pp.180-186
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    • 2006
  • In this study, a large-scale laboratory model test, 2-D and 3-D numerical analyses were conducted to verify the reinforcement effect by utilizing geotextile bag on the railway roadbed. Static loading which simulated train load was applied on the geotextile bag-reinforced railway roadbed and also unreinforced railway roadbed, Computer program named Pentagon which is a part of FEM programs was used in the numerical analysis. Based on the results of laboratory test, 2-D and 3-D numerical analyses, the effect of load distribution and settlement reduction was found to be depending on the geotextile characteristics, tensile strength of geotextite, and interface friction angle between geotextile bags. In general, the result of 2-D and 3-D numerical analyses shows lower value than that of laboratory test. Also, the result of 3-D numerical analyses shows lower value than that of 2-D numerical analyses because of its stress transfer effect.

Settlement Reduction Effect of Advanced Back-to-Back Reinforced Retaining Wall

  • Koh, Taehoon;Hwang, Seonkeun;Jung, Hunchul;Jung, Hyuksang
    • International Journal of Railway
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    • v.6 no.3
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    • pp.107-111
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    • 2013
  • In order to constrain the railway roadbed settlement which causes track irregularity, and thus threats running stability and ride quality, advanced Back-to-Back (BTB) reinforced retaining wall was numerically analyzed as railway roadbed structure. This study is intended to improve conventional Back-to-Back reinforced retaining wall as the technology which would reduce the roadbed settlement in a way of constraining the lateral displacement of its prestressed vertical facing and inducing arching effects in roadbed (backfill) placed between masonry diaphragm wall and vertical facing. As a result of numerical analysis, it was found that the roadbed settlement was reduced by 10% due to the prestressed vertical facing and embedded masonry diaphragm wall of the advanced Back-to-Back reinforced retaining wall system.

Settlement and Bearing Capacity of Roadbed Subjected to Tilting-train Loading in Various Ground Conditions

  • Jeon, Sang-Soo
    • International Journal of Railway
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    • v.8 no.2
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    • pp.35-41
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    • 2015
  • Tilting-train is very attractive to the railroad users in the world due to the advantage of high speed in curved track using pre-existing infrastructure of railway. Tilting-train has a unique allowable speed and mechanism especially in curved track. In this work, when tilting-train is operated with the allowable speed, the behavior of roadbed is evaluated by examining its settlement and bearing capacity. Additionally, the stability of roadbed is estimated as the roadbed is in the condition of soft soil influenced by the weather effects and cyclic train loading. Numerical results show that the roadbed settlement satisfies the allowable settlement when the elastic modulus of upper roadbed should be greater than $5000t/m^2$.

Characteristics of Displacement of the Reinforced Roadbed Materials with Cyclic Loading (동적하중 재하시 강화노반 재료별 침하 특성)

  • 황선근;이성혁;최찬용
    • Journal of the Korean Society for Railway
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    • v.5 no.2
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    • pp.70-76
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    • 2002
  • In this study, performance of reinforced railroad roadbeds with the reinforced roadbed materials were investigated through the real scale roadbed tests. It was also found that the reinforced roadbed with reinforced roadbed materials has less elastic and plastic settlement than the one with soil. The slag roadbed was more effective than the crushed stone roadbed with the same condition for load distribution. Therefore considering overall characteristics of reinforced roadbed material, the optimum thickness was recommended as 50 cm. Furthermore the real scale model test under the simulated rainfall condition, the settlement in the slag roadbed was about 8 times smaller than the settlement in the soil roadbed.

A Study on Wearing of Rail and Adjustment of Cant in Accordance with Increase in Running Speed of Train (열차운행속도 상승에 따른 레일마모 및 캔트조정 연구)

  • Shin, Gil-Cheol;Joo, Bong-Gyu;Chung, Sung-Hyun
    • Proceedings of the KSR Conference
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    • pp.1121-1128
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    • 2007
  • Subway routes $1{\sim}4$ were constructed in gravel roadbed track structure in consideration of the technological capabilities, construction cost and duration at the time of the initial construction. As such, 224.8km, approximately 81.2% of entire length, of total length of railway track at 276.9km was constructed on gravel roadbed. However, improvement of gravel roadbed to concreted roadbed began in 1998 due to problems including frequent repair works and limited time application for such works caused by occurrence of tract distortion during operation as well as lowering of roadbed functions and generation of dust caused by frictional power, impact absorption capabilities, abrasion and crushing of gravel on roadbed. Currently, this improvement is continuing with target of converting entire route into concreted roadbed structure. Therefore, this Study modifies formula for setting cant, analyze the correlation between wearing of rail side of the curvature and cant insufficiency following increasing of the running speed of the train, and to present the directions for fundamental review for adjustment of cant insufficiencies at the time of improvement of gravel roadbed to concreted roadbed that is being implemented on the operational tracks of the railway trains.

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A Study on Wearing of Rail and Adjustment of Cant in Accordance with Increase in Running Speed of Train (속도 상승에 따른 캔트조정 사례 분석)

  • Shin, Gil-Cheol;Yang, Hoe-Seong;Joo, Bong-Gyu;Chung, Sung-Hyun
    • Proceedings of the KSR Conference
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    • pp.151-157
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    • 2008
  • Subway routes $1\sim4$ were constructed in gravel roadbed track structure in consideration of the technological capabilities, construction cost and duration at the time of the initial construction. As such, 224.8km, approximately 81.2% of entire length, of total length of railway track at 276.9km was constructed on gravel roadbed. However, improvement of gravel roadbed to concreted roadbed began in 1998 due to problems including frequent repair works and limited time application for such works caused by occurrence of tract distortion during operation as well as lowering of roadbed functions and generation of dust caused by frictional power, impact absorption capabilities, abrasion and crushing of gravel on roadbed. Currently, this improvement is continuing with target of converting entire route into concreted roadbed structure. Therefore, this Study modifies formula for setting cant, analyze the correlation between wearing of rail side of the curvature and cant insufficiency following increasing of the running speed of the train, and to present the directions for fundamental review for adjustment of cant insufficiencies at the time of improvement of gravel roadbed to concreted roadbed that is being implemented on the operational tracks of the railway trains.

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Characteristics of Roadbed Behaviors of Concrete Track for High-Speed Railway (고속철도 콘크리트궤도용 흙노반의 거동 특성)

  • Lee Il-Wha;Lee Su-Hyung;Kang Yun-Suk
    • Journal of the Korean Society for Railway
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    • v.9 no.3
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    • pp.298-304
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    • 2006
  • An active application of concrete track is being expected for the future constructions of Korean railroad. For the successful concrete track construction and design in earthwork areas, the roadbed behavior should be reasonably estimated using the proper analysis method. In this paper, behaviors of concrete track on the reinforced roadbed constructed with the standard stiffness and depth were estimated thorough numerical analyses and field measurements. A three dimensional finite difference method was employed to model the concrete tracks and subground. The settlement and vertical pressures caused by train load were estimated by the numerical method and compared with the field measurement results. The bearing characteristics of roadbed were presented and the proper method for the analysis of concrete track was proposed.