• Title, Summary, Keyword: 자갈궤도

Search Result 108, Processing Time 0.049 seconds

Field Model Tests on Frost Penetration Depths and Frost Heave Amounts in Ballast track and Concrete track (현장모형실험을 통한 자갈궤도와 콘크리트궤도의 동결심도 및 동상량 측정)

  • Kim, Young-Chin
    • Journal of the Korean Society for Railway
    • /
    • v.19 no.4
    • /
    • pp.506-514
    • /
    • 2016
  • Experimental ballast track and concrete track were installed on the railway site and the frost penetration depth and the frost heave amount in the winter were measured. As a result, when the freezing index was the same, the frost penetration depth of concrete track was deeper than that of ballast track. Furthermore, when an XPS and polyethylene aggregate layer was installed below the ballast track, the frost penetration depth of the ballast track decreased significantly; in the case of the concrete track, the frost penetration depth decreased when the thickness of the subbase increased. Meanwhile, the frost heave amount also decreased when an XPS and polyethylene aggregate layer was installed below the ballast track ; in the case of the concrete track, the frost heave amount decreased when the thickness of the subbase increased.

A Comparison of Behavior of the Roadbeds of Ballasted & Concrete Track with the Cyclic Loading (자갈궤도와 콘크리트궤도에서의 하중재하에 따른 노반거동 비교)

  • Choi, Chan-Yong;Lee, Sung-Heok;Eum, Ki-Young
    • Journal of the Korean Geosynthetics Society
    • /
    • v.9 no.3
    • /
    • pp.1-8
    • /
    • 2010
  • The track systems installed in Korea railway consist of two types on ballasted track or ballastless track. In this study, it was compared with difference of the behaviors at roadbed with cyclic loading through full scale model test. From the results of model tests, loading distribution ratio of the concrete slab track become more widely distributed than ballasted track, and loading distribution ratio at concrete track was about 30:20:15. The concrete slab track is likely to behavior of the rigid plate, while ballasted track is such as flexible pavement. The vertical stresses of upper roadbed with traffic cyclic loading in concrete track were measured about 30 kPa or less. It was a scene very similar to the results of the field train running test. The vertical stress at concrete track was occurred approximately 4 times smaller than ballasted track. Also, the soil velocities with cyclic loading at the slab track were occurred about 0.3 cm/sec or less, its 8 times smaller than ballasted track.

  • PDF

A Study on Effect of Vibration Reduction with Ballast Mat of Ballasted Track in Tunnel (터널내 자갈도상제도의 자갈도상매트 시공 후 진동 저감 효과에 대한 연구)

  • You, Chung-Jun
    • Journal of the Korean Society for Railway
    • /
    • v.12 no.1
    • /
    • pp.167-174
    • /
    • 2009
  • Due to the travelling of the train with high speed the period of maintenance activities of the ballasted track is coming to be short, and more from the residential area of the ballasted track tunnel circumference the civil appeal is increasing with railroad vibration problem. To reduce the vibration problem and a maintenance cost establishes the ballast mat in the tunnel within part segment. In this study, to estimate the vibration reduction effect of the ballast mat we have done a comparative analysis with the vibration field test by the transit train by at the ballasted track with ballast mat and the standard ballasted track without vibration protection in tunnel.

Analysis of Life Cycle Costs of Railway Track : A Case Study for Ballasted and Concrete Track for High-Speed Railway (철도 궤도의 수명주기비용 분석 : 고속철도 자갈궤도와 콘크리트궤도 사례 연구)

  • Jang, Seung Yup
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.20 no.2
    • /
    • pp.110-121
    • /
    • 2016
  • In the decision-making, such as selection of structure, construction method, or time and scheme of maintenance, the evaluation of life-cycle cost(LCC) is of great importance. The maintenance cost occupy a large portion of the LCC of the railway track as well as the initial construction cost. Futhermore, the proportion of the maintenance cost is much higher in the ballasted track. Thus, the importance of the LCC evaluation is higher than in any other engineering structures. In this study, a LCC model that can consider various design parameters such as the type of track structure, annual traffic volume, axle load, train speed, and proportion of curve sections and engineering structures has been developed. Fundamental data for calculating costs also have been presented. Based on the model and data proposed, the trends in the variation of LCC according to the design parameters were examined and the most important design parameters in the LCC analysis of railway track were investigated. The results show that the proportion of renewal and operational costs is much higher in the ballasted track than in the concrete track, and the annual traffic volume and ballast taming period are most significant factors on the LCC of the ballasted track. On the contrary, it is revealed that the proportion of the initial construction costs in the concrete track is much higher, and the LCC of the concrete track is less sensitive to the traffic volume, train speed, and axle load.

Behavior Characteristics of Ballasted Track on Asphalt Roadbed Using Real Scale Test (실대형 실험을 통한 아스팔트 노반상 자갈궤도의 거동 특성)

  • Lee, Seonghyeok;Lee, Jinwook;Lee, Hyunmin
    • Journal of the Korean Society for Railway
    • /
    • v.18 no.3
    • /
    • pp.252-260
    • /
    • 2015
  • Ballasted track on an asphalt roadbed can be beneficial for its various effects such as (i) decreasing of roadbed thickness by dispersing train load; (ii) prevention of both strength reduction and weakening in roadbed system by preventing rainwater penetration; and (iii) reducing maintenance cost by preventing roadbed mud-pumping and frostbite. With these beneficial effects, ballasted track on asphalt roadbed has been widely used in Europe and Japan, and relevant research for applying such ballasted track on asphalt roadbed systems in Korea is ongoing. In this study, full-scale static and dynamic train load tests were performed to compare the performance of ballasted track on asphalt roadbed and ballasted track. The optimum thickness levels of asphalt and reinforced roadbeds, corresponding to the design criteria for reinforced roadbed of high-speed railway, was estimated using the FEM program ABAQUS. Test results show that the earth pressure on reinforced roadbed of ballasted track on the asphalt roadbed was relatively low compared with that of simple ballasted track. The elastic and plastic displacements of simple ballasted track on the asphalt roadbed were also lower than those of ballasted track. These test results may indicate that the use of ballasted track on asphalt roadbed is an advantageous system in view of long-term maintenance.

Evaluation of Applicability of Apparent Track Stiffness Measured by Light-Weight Deflectometer as a Ballasted Track Condition Index (소형동평판재하시험기로 측정한 궤도 겉보기 강성의 자갈궤도 상태평가 지표로서의 적용성 고찰)

  • Choi, Yeong-Tae;Hwang, Sung Ho;Jang, Seung Yup;Park, Bongsik;Shim, Gwang Seop
    • Journal of the Korean GEO-environmental Society
    • /
    • v.19 no.2
    • /
    • pp.37-44
    • /
    • 2018
  • Ballasted track has been widely used due to its flexibility. However, the plastic deformation of ballasted track causes the evolution of track geometrical errors, and hence it requires continuous maintenance; increase in number of trains, weight, and speed expedites maintenance frequency and cost as well. Ballast stiffness is well-known as an indicator of design and maintenance. In this regard, this paper aims to suggest the method to measure ballast track stiffness using light-weight deflectometer (LWD) and thus verify its applicability as a maintenance measure. Preliminary field tests determined simple field testing protocol to measure track stiffness. The apparent ballast stiffness by LWD shows good corelation with TQI (Track Quality Index) and maintenance length. That is, as average of apparent stiffness increase, TQI and tamping length decrease exponentially. Therefore, apparent stiffness can be used as an index for ballast condition assessment.

The Evaluation of Track Impact Factor on the Various Track Type in Urban Transit (도시철도 궤도구조별 궤도충격계수 평가)

  • Choi, Jung-Youl;Park, Yong-Gul;Lee, Sang-Min
    • Journal of the Korean Society for Railway
    • /
    • v.14 no.3
    • /
    • pp.248-255
    • /
    • 2011
  • Impact factor of concrete and ballast track which has been used in Korea railway was applied to equation (1+0.513V/100) from AREA. As the use of this equation, overcapacity of track design might be occurred. Therefore, this study compared impact of ballast track (well, bad) and concrete track (sleeper embeded system, rail floating and sleeper floating) by field test to analyzing dynamic effect of track structure's characterstic and wheel load on service line. In addition, it suggested a method to generate reasonable impact factor on each track type.

An Estimate of Ballast Track Condition on Dynamic Behavior of Railway Bridge (철도교량의 동적거동 특성을 고려한 자갈도상궤도의 상태추정에 관한 연구)

  • Kweon, Oh-Soon;Choi, Jung-Youl;Kang, Myoung-Seok;Lee, Hee-Up;Park, Yong-Gul
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.480-493
    • /
    • 2007
  • Many railway-advanced countries are using the various types of track to reduce the track maintenance and repair cost according to the improvement of velocity. It spends on much maintenance and repair cost for ballast track due to abrasion of ballast, track irregularity and unisotropical ballast-support stiffness. The ballast track on railway bridge is accelerating the deterioration of ballast according to interaction of railway bridge and track. As continuing the deterioration, it is caused dynamic loads. Due to these effects, it increases negative loads of track and bridge. However, when designing the railway bridge, the effect of ballast track was applicate only dead load, so elastic behavior effect of ballast track is not influenced. Therefore, this paper presumes the stiffness of ballast track on railway bridge considering dynamic behavior of railway bridge, it was evaluated that effect on dynamic behaviors of railway bridge according to ballast track stiffness.

  • PDF

Evaluation of the Optimal Vertical Stiffness of a Fastener Along a High-speed Ballast Track (고속철도 자갈궤도 체결구 최적 수직강성 평가)

  • Yang, Sin-Choo;Kim, Eun
    • Journal of the Korean Society for Railway
    • /
    • v.18 no.2
    • /
    • pp.139-148
    • /
    • 2015
  • By increasing the vertical stiffness of the rail fastening system, the dynamic wheel load of the vehicle can be increased on the ballast track, though this increases the cost of track maintenance. On the other hand, the resistance acting on the wheel is decreased, which lowers the cost of the electric power to run the train. For this reason, the determination of the optimal fastener stiffness is important when attempting to minimize the economic costs associated with both track maintenance and energy to operate the train. In this study, a numerical method for evaluating the optimal vertical stiffness of the fasteners used on ballast track is presented on the basis of the process proposed by L$\acute{o}$pez-Pita et al. They used an approximation formula while calculating the dynamic wheel load. The evaluated fastener stiffness is mainly affected by the calculated dynamic wheel load. In this study, the dynamic wheel load is more precisely evaluated with an advanced vehicle-track interaction model. An appropriate range of the stiffness of the fastener applicable to the design of ballast track along domestic high-speed lines is proposed.

Analysis on Factors Affecting the Vibration of the Ballast Track in Kyeong-Bu High Speed Line (경부고속선 자갈궤도의 진동에 영향을 미치는 인자에 대한 분석)

  • Kim, Man-Cheol
    • Journal of the Korean Society for Railway
    • /
    • v.10 no.5
    • /
    • pp.463-472
    • /
    • 2007
  • In this paper, the correlation between the vibration characteristics of the track components and the parameters affecting the vibration is analysed. To do it, the accelerations of each track component such as rails, sleepers and ballast are measured in Kyong-Bu high-speed line. The RMS values of the measured data are calculated and the pad stiffness, the longitudinal irregularity, running velocity and the corrugation, are considered as the parameters in the viewpoint of track. By using the linear regression, the correlation coefficient is calculated to analyse the relationship. Also, the 1/3 Octave analysis is calculated to analyse the dominant frequency band of tile vibrations of the track components.