• Title/Summary/Keyword: railway ballast

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Breakage Characteristics of Ballast (도상자갈의 마모/파쇄 특성)

  • 정근영;김현기;이종득
    • Journal of the Korean Society for Railway
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    • v.2 no.3
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    • pp.61-69
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    • 1999
  • The durability of ballast plays an important role in track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several scholars. The deterioration characteristics is very important factor in the behaviour of track and its life. In this paper, abrasion/breakage characteristics of ballast is studied to see the effect of physical ballast characteristics on ballast life. To reveal breakage characteristics of ballast, the ballast box test and the MTT field test were carried out. The breakage characteristics studied in this paper is applied to the ballast life prediction in various conditions, such as LA abrasion, annual tonnage, tamping number per year, etc

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Evaluation of Low Velocity Impact Damage and Compressive Strength After Impact for Laminate Composites Applied to Lightweight Bogie Frame Induced by Flying Railway Ballast (도상자갈 비산에 의한 경량 대차프레임 적용 적층 복합재의 저속충격 손상 및 충격 후 압축 강도 평가)

  • Goo, Jun-Sung;Shin, Kwang-Bok;Kim, Jung-Seok
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.2661-2665
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    • 2011
  • In order to evaluate the structural integrity of a GFRP composite bogie frame due to flying railway ballast, the low velocity impact test and compressive test after impact was conducted for glass fiber/epoxy 4-harness satin woven laminate composites applied to skin part of a bogie frame. The impact test was performed using a instrumented impact testing system with energy levels of 5J, 10J and 20J and the designed impactor based on typical railway ballast shapes such as sphere, cube and cone to simulate the ballasted track environments. The compressive strength was tested to according to ASTM D7137 to evaluate the degradation of mechanical property of impact damaged laminate composites. The results showed that the damage area and the degradation of compressive strength after impact for laminate composites was increased with increase in impact energy for all ballast shapes and was particularly most influenced by cone ballast shape.

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A study on availability of GPR in estimating the condition of ballast (자갈도상 상태평가를 위한 GPR기법의 적용성 분석)

  • Lee, Choon-Kil;Kim, Nam-Hong;Woo, Byoung-Koo;Kim, Kwan-Hyung
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.494-499
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    • 2007
  • The ballast, one of a track components, plays an essential role as intermedium in transmitting train traffic-load to subgrade safely, and deterioration of ballast caused by cumulative load effects growth of track irregularity. Especially in the case of Gyeongbu high-speed railway, the deteriorating speed of ballast by dynamic vibration is faster than conventional line because KTX is longer than normal trains in length and it's velocity is very fast with high speed of 300km/h as well. In addition, ballast is a nonlinear material contrary to ordinary metal which has homogeneous property and this property of ballast may cause transformation of ballast. Therefore the theoretical modeling of ballast is quite complicated and it is hard to ensure the reliability of the result. The objective of this paper is to examine the availability of GPR(Ground Penetrating Radar) in estimating the thickness and the degree of deterioration of ballast. First, We figured out the principle of GPR which is the technique of evaluating the condition of ballast and then analyzed data which were measured at Gyeongbu high-speed railway where KTX is running now.

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A Study on Dynamic characteristics in the Ballast gravel in Gyeongbu High Speed Railway (경부고속철도 토공부의 자갈도상에 대한 진동특성 연구)

  • Park, Jun-O;Kang, Tae-Ku;Hong, Won-Pyo
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.84-90
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    • 2009
  • The gravel ballast in the ballasted track has the function to not only transfer/scatter the train loads to subgrade through rail and sleeper but also elastically support the train loads. Because track irregularities results inevitably from the repetitive train loads, the track maintenance should be undertaken for correcting them. By analyzing the track maintenance history in the Gyeongbu high speed railway, this study tries to choose the local two spots in the railway in which the repair frequencies are maximum and relative small; to analyze their dynamic characteristics as well as grade; and to compare them with maintenance history. As the dynamic characteristics of track, the vertical displacement and vibrating acceleration of sleeper as well as acceleration of ballast are measured/analyzed. Furthermore, by collecting soil and gravel on the reinforced roadbed and undertaking ballast screening test, the size distributions are compared with grade distribution standards of high speed railway.

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A Study on the Dynamic Behaviors of Ballast Track using Field Test (현장측정을 통한 자갈도상궤도의 동적 거동 분석)

  • Park Yong-Gul;Choi Jung-Youl
    • Journal of the Korean Society for Railway
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    • v.9 no.4 s.35
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    • pp.401-411
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    • 2006
  • The major objective of this study is to investigate the dynamic behaviors of track due to the deterioration characteristics of ballast for servicing tracks by the field test. The durability of ballast plays an important role in the track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several scholars. The deterioration characteristics of ballast is one of the most important factor in the dynamic behaviour of track and its life. In this paper abrasion/breakage characteristics of ballast is studied to predict the effect of physical ballast characteristics on ballast track. To reveal deterioration characteristics of ballast, the field test were carried out. The deterioration characteristics, studied in this paper, is applied to the dynamic behaviour of track in various conditions.

An Experimental Study of Diminution of Ballast Track Bridges Vibration due to the Variation of Ballast Depth (도상두께 변화에 따른 유도상교량 궤도 진동저감의 실험적 연구)

  • Kwon, Soon-Jung;Lee, Sang-Bae;Hong, Cheng-Hi
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1222-1229
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    • 2011
  • Railway bridges are divided into ballastless and ballast track bridges. The ballast abrasion occurs on the ballast track upon bridges more than soil roadbed because the track vibration occurs a lot in the ballast track upon bridges due to girder vibration when a train's weight is loaded onto track even though the identical ballast is used. The phenomena of mud pumping especially, which occurs when drainage is not properly secured for heavy rain, leads to the increase of maintenance work load and the decline of ride comfort. There are countermeasures such as ballast change, installation of cross-drainage for poor drainage, gutter establishment, ballast lifting methods, ballast mats and resilient sleepers laying for the mud pumping. The ballast thickness range in domestic railroad construction rule is uniformly set up according to the design speed of railroad and passing tonnage of train without considering field conditions which is considered in foreign railroad companies. The purpose of this study is to verify the effect of vibration decrease by measuring the acceleration, displacement and ride comfort of ballast track with the change of ballast thickness on the ballast track bridges and to suggest the optimal height of ballast on the Yocheon Bridge built for the test in Honam Line.

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A study on the Steel Plate Girder Railway bridge in the applying External Post-tensioning Method (강철도교에 대한 외부 후긴장 보강공법의 적용에 관한 연구)

  • Choi Jung-Youl;Park Yong-Gul;Byun Jong Gul
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1034-1039
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    • 2004
  • The major objective of this study is to investigate the effects and application of reinforcement for steel plate girder railway bridge by the external prestressing method. It analyzed the mechanical behaviors of non-ballasted railway bridge with ballast reinforced and external post-tensioning reinforced on the finite clement analysis for the static and dynamic behavior. As a result, the reinforcement of ballasted railway bridge the external prestressing method are obviously effective for the additional dead force which is ballast. The analytical study are carried out to investigate the post-tension force decrease bending behavior and deflection in composite bridge for serviceability. To develop two type FEM model which reflect well the post-tension force transverse distribution behavior of servicing bridge. With the comparing the results of railway bridge with ballast which carried out before the post-tensioning with the results of railway bridge with ballast which carried out after post-tensioning, It is investigated that the additional dead load decrease effect and bending behavior of servicing bridge is effect by the post-tensioning. The reinforcement by using the external tendon can be reducing that structure of a degradation phenomenon by unusual stresses due to additional dead load and other problems.

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A Study on the Assessment of Track Stabilization on Ballast Cleaning work site (크리너 작업구간 선로안정화 상태평가에 관한 연구)

  • Jeon, Il-Sik;Lee, Syeung-Youl;Choi, Hyoung-Su;Kim, Han-Chip
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.268-274
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    • 2011
  • In railway, Ballast plays an essential role as intermedium in transmitting train load to subgrade safely. Gyoung-Bu HSL 1st phase consists of ballasted track except for over 5km long tunnels. Ballast track occurred track irregularity by train loads and requires periodic maintenance work. However, Repetitive train operation and tamping work cause to accelerate track irregularity and ballast deterioration such as abrasion and crushing. For these reason, Track irregularity areas had occurred ballast cleaning work to improve track quality. However, for the train to run safety, ballast cleaner working area needs train speed reduction and track stabilization work due to ballast relaxation and initial settlement. In this study, according to train speed-up and cumulative traffic tonnage, we measured and analyzed the track settlement and acceleration of sleepers to evaluate of track stabilization in order to keep the ballast condition stable after cleaning work.

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A Study on the Influence of Track Stability for Ballast Resistance Force (도상저항력이 궤도 안전성에 미치는 영향)

  • 박준명;이방우;박선규;이종득
    • Journal of the Korean Society for Railway
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    • v.6 no.3
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    • pp.169-173
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    • 2003
  • Transportation by railroad is superior to other transport in a mass transport, stability, rapid transit, delightfulness and low-pollution etc. But, it need to ensure a track stability that supports the train-load for high-speed in transportation by railroad. Ballast resistance force resists against the buckling of track taking a rail-tie's place. So, it plays an important role in a careful train-service. So, in this papers, we forced on measuring and theorizing about the Ballast Resistance Force that play a key role in track stability and high-speed. And we studied the mechanical property. Finally, we suggested the method of securing Ballast Resistance Force and the report for a careful train-service in high-speed.

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
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    • v.19 no.4
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    • pp.506-514
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    • 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.