• Title, Summary, Keyword: roadbed settlement

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A Study on the Settlement Prediction of Reinforced Roadbeds (고속전철 강화노반의 침하예측에 관한 연구)

  • 황선근;신민호;이일화;조용권
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.346-353
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    • 2000
  • The benefit of reinforced roadbeds, such as roadbed reinforced with slag and roadbed with crushed stone has been known among engineers. In this study, model soil box test is executed to determine optimum roadbed thickness. As a result, a empirical solution for the settlement of reinforced roadbeds was suggested. Furthermore, optimum thickness of reinforced roadbed could be determined based on the settlement characteristic of reinforced roadbed among the several variables.

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A Study on the Criteria of Settlement in Concrete Slabtrack (토노반상 콘크리트궤도의 노반허용침하기준설정에 관한 연구)

  • Hong, Chul-Kee;Yang, Shin-Chu;Kim, Yun-Tae
    • Journal of the Korean Society for Railway
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    • v.10 no.3
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    • pp.355-364
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    • 2007
  • Recently a concrete slab tracks are being constructed on roadbed in the Gyoeng-bu 2nd phase high speed railways. In respdnding to this trend, new design standards and track materials maintenance systems, based on the slab track material safety and usage perspective, are needed. This research provides a roadbed design criteria and the maintenance system. The proposed roadbed design criteria and the maintenance system are based on the developed analysis meathod of train/slab-track interaction. where the roadbed settlement and train speed are utilized as mediating variables. In the analysis, the dynamic response of train/slab-track interaction apply to various speeds and settlements. the roadbed settlement is shown in a sinusoidal shape of wave, the scope of the settlement occurrence presented in its wavelengths, include 6meters, 10meters, 15merwes, 20meters, 30meters. The train speeds involved are 50, 100, 150, 200, 250, 300, 350, 400kilometers per hour.

Characteristics of Behavior of the Crushed Stone Reinforced Roadbed under Cyclic Loading (동적하중 재하시 쇄석강화노반의 거동 특성)

  • 황선근;이성혁;이일화;최찬용
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.525-532
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    • 2001
  • In this study, performance of reinforced railroad roadbeds with the crushed stones was investigated through the real scale railroad roadbed tests. Several real scale reinforced railroad roadbeds were constructed in the laboratory with different subgrade conditions and were tested with the estimated actual train loads including the impact loading of train. The affecting factors such as settlement, earth pressure and stress change at the surface of reinforced roadbed, subgrade layers as well as surface of rails were measured. It was found through the actual testing that for the roadbed with the same thickness, the settlement and vibration level (velocity) of reinforced roadbed decreases with the increase of reaction modulus of subgrade. The settlement of reinforced roadbed with the same reaction modulus of subgrade also decreases with the increase of thickness of the reinforced roadbed.

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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.

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 $5000t/m^2$.

Effect of Settlement Restoration Grouting between concrete track/Roadbed on the train service stability (콘크리트궤도 침하복원을 위한 궤도/노반 인터페이스부 그라우팅이 주행안정성에 미치는 영향)

  • Lee, Il-Wha;Lee, Sung-Jin;Lee, Tae-Guen;Kang, Tae-Ho
    • Proceedings of the KSR Conference
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    • pp.796-804
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    • 2008
  • Various design factors should be considered in order to apply the concrete slab track system on the soil/rock roadbed. One of the important factors is the settlement of roadbed. This settlement of concrete track should be supervised under the allowable settlement limit. If the settlement of roadbed under the concrete track exceed the allowable limit, the train serviceability will considerably come down and furthermore the fatal disaster may happen. Therefore, in this paper we introduced a digitalized grouting method as a settlement restoration method that can be suitably adopted to the concrete slab track. And we also evaluated the train service stability through the analysis of the track behavior according to the difference of the stiffness between the grouted part and the original roadbed.

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Study of the Long-Term Behavior Characteristics of Roadbed on Concrete Track of High-speed Railway (고속철도 콘크리트 궤도상 토공노반의 장기거동 특성 연구)

  • Choi, Chan-Yong;Jung, Jae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.8-16
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    • 2018
  • This study examined the long-term behavior of a roadbed using high-speed railway concrete track and roadbed measurement data and evaluated the long-term performance of the track and roadbed. Recently, high-speed railway track type has been adopted as a concrete slab. On the other hand, the concrete track is vulnerable to roadbed settlement. In the case of gravel tracks, it is easy to restore the original state by maintenance even if the roadbed settles. On the other hand, in the case of the concrete track, if excessive settlement of the roadbed occurs, cracks are generated continuously on the slabs and sleepers, resulting in greatly reduced usability. For this reason, it is difficult to restore the original state only by partial maintenance. In this paper, a long-term performance evaluation was carried out on a concrete track during operation by monitoring the measurement data of sensors buried from the beginning of construction for approximately 3 years after the high-speed railway opened. Performance evaluation methods include a performance evaluation of track/roadbed when the train passes, long-term track and roadbed performance evaluation, analysis of the track/roadbed effect on long-term settlement and analysis of the factors influencing long-term settlement. The trail response of KTX-Sancheon was greatest in the track/roadbed performance evaluation by train. The results of the long-term track and roadbed performance evaluation were measured within the standard values. The track and roadbed performance impact assessment with long-term settlement was strongly related to TCL settlement. The influences of the water content and groundwater level were verified by analyzing the external factors of long-term settlement. Through such a method, the stability of a track/roadbed can be secured.

Settlement Characteristics of the Reinforced Railroad Roadbed with Crushed Stones Under a Simulated Train Loading (모사 열차하중 재하에 따른 쇄석강화노반의 침하특성)

  • Hwang, Seon-Keun
    • Journal of the Korean Geotechnical Society
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    • v.20 no.2
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    • pp.5-13
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    • 2004
  • Conventional railroad roadbeds constructed with soils can easily deteriorate with time due to the increase of repeated traffic loading, increase of train speed, built-up of ground water on the roadbed and decrease of permeability in the roadbed layer, etc. In this study, performance of reinforced railroad roadbeds with the crushed stones was investigated through the real scale roadbed tests and numerical analysis. It was found that the reinforced roadbed with crushed stone had less elastic and plastic vertical displacement(settlement) than general soil roadbed regardless of the number of loading cycles. It was also found through the actual testing that for the roadbed with the same thickness, the displacement of reinforced roadbed decreases with the increase of subgrade reaction modulus. The settlement of reinforced roadbed with the same subgrade reaction modulus also decreases with the increase of thickness of the reinforced roadbed. However, the subgrade reaction modulus is a more important factor to the total plastic displacement of the track than the thickness of the crushed stone roadbed.

The Characteristics of Settlement on the Roadbed Reinforcement Materials of Cyclic Loading with a Falling Water (반복재하 하중을 받는 철도노반재료의 강우에 따른 침하 특성)

  • 황선근;최찬용;이진욱;오상덕
    • Proceedings of the KSR Conference
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    • pp.562-567
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    • 2001
  • In this study, performance of reinforced railroad roadbeds with the slag(HMS-25) and soil were investigated through the real scale railroad roadbed tests. Several real scale reinforced railroad roadbeds were constructed in the laboratory with different subgrade conditions and were tested with the estimated actual train loads including the impact loading of train. The affecting factors such as plastic & elastic settlement roadbed layers as well as surface of rails were measured. The settlement at rail surface and roadbed surface of case of soil and slag roadbed comparative with good roadbed site were 2.3, 5.7 times and 1.9, 1.6 times, respectively.

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