• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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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.

• 한국철도학회논문집
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• 제10권3호
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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.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.191-198
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• 2000

Dynamic fatigue test is carried out using soil model box for the evaluation of performance of three different roadbed materials. Bearing capacity, settlement and mud pumping phenomenon of each roadbed materials as well as penetration of model ballast into the roadbeds are investigated. It was found that settlement of slag and crushed stone roadbed is smaller than the soil roadbed during dynamic fatigue test with same initial conditions.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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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.

• 한국철도학회논문집
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• 제5권2호
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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.

• International Journal of Railway
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• 제6권3호
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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.

• International Journal of Railway
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• 제8권2호
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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 $5000t/m^2$.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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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.

• 한국산학기술학회논문지
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• 제19권4호
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• pp.8-16
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• 2018

본 논문의 목적은 고속철도 콘크리트 궤도 및 노반 측정 데이터(노반압력, 진동가속도, 탄성변위 등)를 이용하여 토공노반의 장기거동을 분석하고 궤도 노반의 장기성능을 평가하고자 하는데 있다. 최근 고속철도 궤도 형식이 콘크리트 슬래브로 채택되고 있다. 그러나 콘크리트 궤도는 노반 침하에 취약하다. 자갈궤도의 경우 노반이 침하되어도 유지보수로 원상복구가 용이하다. 반면에 콘크리트 궤도의 경우 노반의 과도한 침하가 발생하면 도상 및 침목에 균열이 지속적으로 발생되고 사용성이 크게 저하된다. 이와 같은 이유로 부분보수만으로 원상복구가 어렵다. 본 논문에서는 운영 중 콘크리트 궤도에 대하여 건설 초부터 매설된 센서의 측정 데이터를 개통 후 약 3년까지 모니터링하여 장기성능평가를 수행하였다. 성능평가 방법은 열차별 궤도 토공노반 및 장기 궤도 노반 성능평가, 장기침하에 따른 궤도 노반 성능 영향 분석 및 장기 침하 영향인자 분석 등이다. 열차별 궤도 노반 성능평가에서는 KTX-산천중련의 노반응답이 가장 컸다. 장기 궤도 노반 성능평가 결과는 측정항목이 기준치이내로 측정되었다. 장기침하에 따른 궤도 노반 성능영향 평가는 TCL처짐은 침하와 깊은 연관이 있는 것으로 분석되었다. 장기침하의 외부영향인자 분석을 통해 함수비와 지하수위의 영향성을 확인하였다. 이와같은 방법을 통해 궤도상 토공노반의 안정성을 확보할 수 있을 것으로 사료된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.407-414
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• 2000

Recently the geogrids are being used in some large projects such as Inchon International Airport construction, highway construction, and Korean High-Speed Railway construction with not only the merit of simple construction but also reinforcing efficiency for the soft ground. Main function of roadbed is to provide a stable foundation in terms of bearing capacity and settlement for the subballast and ballsat layers. Differential settlement of the railroad should be avoided. The cyclic laboratory model tests were performed to investigate the settlement behavior of geogrid reinforced railroadbed. The ratio of settlement of roadbed under cyclic loading with three layers of geogrid reinforced is less than 1/2 of the roadbed thickness without reinforcement.