• Title/Summary/Keyword: railroad roadbed

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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.

Long-Term Measurement under the Moving train at the Test Reinforced Roadbed Site in Railway (철도강화노반 시험부설구간에서의 열차 주행시 장기거동 계측)

  • 황선근;신민호;이성혁;최찬용;이시한
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.223-230
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    • 2001
  • Nine different types of the reinforced railroad roadbeds which . are located in between Suwon-Chunan station of Kyongbu line were constructed in order to increase the bearing capacity of railroad roadbed and to improve the ridability as a part of speed-up project of conventional railroad systems. Each three sections were composed of weathered granite soil, crushed stone and furnace slag(HMS25), and fully instrumented with earth pressure cells, settlement plates and geophones to monitor the behavior of roadbeds under actual train loads. Field measurement has continued since October 31, 2000 and presently with rather longer measurement interval. The measurement data such as settlement, earth pressure and vibration levels are currently under analysis process. In this paper, only cumulative measurement data of railroad roadbeds were introduced. In the near future, comprehensive measurement data and result of analysis will be presented and design technique for the reinforced railroad roadbed will be proposed as a final product of this study.

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Trend of the track irregularity with reinforced Railroad Roadbed materials measuring in Service Railroad line (실 열차구간에서 측정된 강화노반재료별 궤도틀림 진행 평가)

  • Choi, Chan-Yong;Lee, Jee-Ha;Park, Chang-Woo;Kim, Sung-Soo
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.1833-1837
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    • 2007
  • The railroad roadbed plays an important role in distributing and transferring the train loading to subgrade, preventing subgrade from bearing softened by providing appropriate stiffness for subgrade, and eventually supporting the track structures. Presently, the reinforced roadbed was widely constructed in high speed line and is proceeding a research about economical thickness and methodologies for the design of reinforced roadbed. Field test section is located at Kongbu line which is from Suwon to Pungtack. In this study, field test were measured a track irregularity with several types of reinforced roadbed materials by using Track Master. The field testing were conducted between March, 2006 and March, 2007.

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Study on the Resonance in Trackbed of High-Speed Railway Considering Ground Condition (지반조건에 따른 고속철도 토공노반의 공진에 관한 연구)

  • Lee, Il-Wha;Hwang, Seon-Keun;Choi, Chan-Young
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.1320-1325
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    • 2006
  • When the train running on the high-speed track, there is a speed band which track distortion is unusually increased according to the condition of track and roadbed. This speed is called critical velocity and physical parameter values are increased greatly. These phenomenon happened as high-speed train were developed, studied regularly through TGV 100 running test in France. As research result until now, the main reason is soft roadbed's bearing capacity. Wave propagation and track support capacity is varied by the ground characteristics. This paper achieved theoretical examination about resonance band(speed and frequency) that occurred in roadbed on the base rock in point of geotechnical engineering. The examination of resonance divides with ground response analysis, critical band analysis by the shear wave velocity of roadbed and train critical speed through the ground stratum.

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A Review on Intelligent Compaction Techniques in Railroad Construction

  • Oh, Jeongho
    • International Journal of Railway
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    • v.7 no.3
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    • pp.80-84
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    • 2014
  • The purpose of this paper was to review Intelligent Compaction (IC) techniques, which is regarded relatively new to the railroad roadbed construction activity. Most of civil structures are built on roadbed that supposed to provide adequate load bearing support to the upper structure through the qualified compaction process. However, it is not uncommon for structure failure attributed to inadequate compaction control take place in field sites. Unlike traditional compaction control method to check field density at several locations, IC techniques continuously measure various compaction quality indices that represent compaction uniformity. In this paper, a series of literature review relevant to IC techniques was conducted to provide concise summary on the following categories: 1) background of IC technique; 2) Summary of IC vendors and basic principles; 3) modeling of IC behavior, and 4) case study along with correlation between IC with other measurements. In summary, IC technologies seem to be promising in future railroad construction to achieve better compaction quality control so that the serviceability of railroad can be ensured with minimizing rehabilitation and maintenance activities.

Evaluation of Applicability of HMS-25 as the Railroad Roadbed Material (철도 노반재로서의 수경성 입도 조정 고로슬래그(HMS-25)의 적용성 평가)

  • 황선근;이성혁;이시한;최찬용
    • Journal of the Korean Geotechnical Society
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    • v.16 no.1
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    • pp.157-165
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    • 2000
  • The applicability and performance of HMS-25 as the railroad roadbed materials were evaluated through the model and laboratory tests. The uniaxial compression test of HMS-25, model soil box test, and combined resonant column and torsional shear test were performed for static and dynamic analysis of railroad roadbed. The uniaxial compression test result of HMS-25 shows steady increase in strength due to hardening chemical reaction between HMS-25 and water. The result of model soil box test reveals that railroad roadbed of HMS-25 is better than that of soil in several aspects such as bearing capacity and settlement. The combined resonant column and torsional that shear test result indicates that shear modulus of HMS-25 increases with the power of 0.5 to the confining pressure and that shear modulus increases with the increase of curing period.

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Trend of the Long-term track irregularity with Reinforced Railroad Roadbed materials (강화노반재료별 장기 궤도틀림 진행 평가)

  • Choi, Chan-Yong;Lee, Jee-Ha;Park, Tae-Hwan
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.281-285
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    • 2008
  • The railroad roadbed plays an important role in distributing and transferring the train loading to subgrade, preventing subgrade from bearing softened by providing appropriate stiffness for subgrade, and eventually supporting the track structures. Presently, the reinforced roadbed was widely constructed in high speed line and is proceeding a research about economical thickness and methodologies for the design of reinforced roadbed. Field test section is located at Kyungbu line which is from Suwon to Cheonan In this study, field test were measured a track irregularity with several types of reinforced roadbed materials by using Track Master. The field testing were conducted between March, 2006 and April, 2008.

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Prediction of Cumulative Plastic Displacement in the Concrete Track Roadbed Caused by Cyclic Loading (반복하중에 의한 콘크리트 궤도 노반의 누적 소성 변위 예측)

  • Won, Sang-Soo;Lee, Jin-Wook;Lee, Seong-Hyeok;Jung, Young-Hoon
    • Journal of the Korean Society for Railway
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    • v.17 no.1
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    • pp.52-58
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    • 2014
  • Plastic deformation of roadbed influences the stability and maintenance of concrete slab track. Long-term plastic deformation in a railway roadbed is generated primarily due to accumulated inelastic strains caused by repeated passing of trains. Prediction of cumulative plastic deformation is important in cost-effective maintenance of railway tracks as well as for the safe operation of trains. In this study, the vertical displacements in railway roadbeds with different thicknesses of reinforced roadbed were computed. Parameters of the power model for cumulative plastic strain were calibrated by using the data from triaxial tests and full-scale loading tests. Results of three-dimensional finite element analyses of standard roadbed sections provide us with design guidelines for the selection of the thickness of reinforced roadbed.

Dynamic behavior of Track/Roadbed with Loading Frequency in Concrete Track through Full Scale Model Test (실대형 실험을 이용한 가진주파수 변화에 따른 콘크리트궤도의 동적평가)

  • Choi, Chanyong;Kim, Hunki;Eum, Kiyoung;Kang, Yunsuk
    • Journal of the Korean Geosynthetics Society
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    • v.13 no.3
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    • pp.39-47
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    • 2014
  • In this study, the full scale model tests were performed with track-roadbed system such as Ho-nam high speed railway. The measured data gives good similar a roadbed pressure with equivalent depth to the Odemark's theory. In the case of earth pressures have a under 50 kPa at upper-subgrade applying 330 kN static loading. Results of cyclic loading tests did not differ significantly from those of static loading test. The elastic displacement at HSB layer has a level of 1/100 compared to the 1 mm that it was evaluation criteria for speed up of High Speed Railway. Elastic displacement at subgrade layer was measured a level of 1/175. The dynamic characteristics of track-roadbed with loading frequency level were linearly increased under 35 Hz, while the wheel loading, displacement and acceleration of roadbed were decreased loading frequency above 35 Hz.