• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2057-2063
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• 2011

Recently, concrete slab track is mostly used to satisfy requirements for safety of high-speed train operation and economical efficiency of maintenance. Due to structural characteristics of ballast track structures, roadbeds under the ballast experience a state of high stress. In case of slab track structures, however, its roadbeds place on a condition of low stress less than roadbeds of ballast track structures as increasing of the loading area. In this study, vertical earth pressure under slab track structures was investigated through real-scale loading tests and theoretical analysis to compare with each other.

• 한국지반환경공학회 논문집
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• 제19권2호
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• pp.37-44
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• 2018

자갈궤도는 그 유연성으로 인해 전세계적으로 널리 쓰이고 있다. 그러나 소성 변형이 발생하여 궤도선형오차가 증가하므로 지속적인 유지관리가 필요하며, 최근 통과톤수, 열차중량, 속도 증가 등으로 유지보수 비용과 횟수가 증가하고 있다. 자갈궤도 강성이 거동의 중요 지표로 알려져, 소형동평판시험기(LWD)를 레일과 침목이 체결된 상태에서 실험을 하여 궤도 겉보기 강성을 측정하였다. 예비실험을 통하여 현장시험법을 결정하였고, 측정한 겉보기 강성과 TQI(Track Quality Index), 유지관리지표와의 상관성을 분석한 결과, 평균강성이 증가함에 따라 TQI와 탬핑연장이 지수함수적으로 감소함을 밝혔다. 이로부터 겉보기 강성을 궤도상태지표로써 사용가능함을 제시하였고, 향후 정량적인 유지관리지표를 개발할 수 있을 것으로 기대된다.

• 한국안전학회지
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• 제33권2호
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• pp.152-157
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• 2018

The degradation and damage of the components for ballasted track could be caused a serious problem for railway safety. Therefore, the integrity evaluation of ballasted track condition is important to ensure and predict that the track safety and track maintenance. Various track components such as rail pad, ballast, sleeper, and rail that are widely used in Republic of Korea and represent a range of physical properties have been selected for this research. In this study, the experimental modal analysis was performed by the non-destructive testing. Modal test results were obtained from the field test and used to assess the condition of the track components. From the field test, the system of ballasted track was found to be simplified as a two-degree-of-freedom(2DOF) dynamic system. The condition of track component was found to directly affect the dynamic response of ballasted tracks. As the results, the dynamic properties of the track component was depend on the track condition and was distributed more roughly and over a wider range than its initial design values. Further, the methodology presented in this study is possible to determine experimentally the fundamental track parameters which are required in the numerical analysis, and also are useful for the safety assessment of track condition.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.479-486
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• 2000

최근에 철도분야에서는 철도차단시간을 최소화하는 상태에서 현장케도의 동적성능을 향상시키고자하는 노력이 지속되어 왔다. 본 연구에서는 철도케도의 거동 및 동특성규명을 위해 운행선 궤도를 대상으로 도상안정제 살포 전ㆍ후 열차주행시험, 횡저항력시험 및 정ㆍ동적해석을 실시하였다. 이들 결과를 토대로 도상안정제의 효과를 확인하였으며, 아울러 궤도상태를 나타내는 궤도계수 산출을 위한 도표와 도상궤도 구성요소의 진동 및 하부구조로 전달되는 분포력 저감방안을 제시하였다. 본 연구에서 제시되는 결과는 향후 궤도상태판정 및 유지관리를 위한 기초자료로서 널리 이용될 수 있을 것으로 판단되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1827-1832
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• 2007

The purpose of a railway track is to provide a smooth surface for safe and economical train transportation. The performance of the track results from a complex interaction of the track and subgrade components in response to train loading and environmental actions. In the past, the role of subgrade as the track foundation were not recognized adequately. There are insufficient information and inadequate methods for subgrade design, assessment and improvement. This situation has survived for a long time largely because a subgrade defect can often be adjusted by adding more ballast under the ties or applying more frequent track maintenance. Therefore, the application of reinforced roadbed technology will be expected to increase in the future. The reinforced roadbed thickness is set depending on subgrade reaction modulus$(K_{30})$ in the condition of upper subgrade through PBT in both conventional railroad and KTX railroads. As train velocity (V), train passing tonnage (N), and train axial load (P) are not considered in design, the roadbed thickness could be overestimated (or underestimated). Therefore, In this study, the computer model, GEOTRACK, was analyzed the influence of reinforced roadbed thickness factors on track modulus and the characteristics of stress pulses in track and subgrade generated by repeated axle loading.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1279-1286
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• 2007

The purpose of a railway track is to provide a smooth surface for safe and economical train transportation. The performance of the track results from a complex interaction of the track and subgrade components in response to train loading and environmental actions. In the past, the role of subgrade as the track foundation were not recognized adequately. There are insufficient information and inadequate methods for subgrade design, assessment and improvement. This situation has survived for a long time largely because a subgrade defect can often be adjusted by adding more ballast under the ties or applying more frequent track maintenance. Therefore, the application of reinforced roadbed technology will be expected to increase in the future. The reinforced roadbed thickness is set depending on subgrade reaction modulus($K_{30}$) in the condition of upper subgrade through PBT in both conventional railroad and KTX railroads. As train velocity (V), train passing tonnage (N), and train axial load (P) are not considered in design, the roadbed thickness could be overestimated (or underestimated). Therefore, in this study has proposed a determination method of reinforced roadbed thickness using design chart made by resilience modulus and properties of earthwork materials.