도시철도 장기 사용레일의 피로수명 평가

공선용,성덕룡,박용걸,Kong, Sun-Young,Sung, Deok-Yong,Park, Yong-Gul 대한토목학회 2013 대한토목학회논문집 Vol.33 No.2

최근 연구결과 레일연마 및 장대레일화를 통해 누적통과톤수에 의한 레일교체기준의 연장이 가능한 것으로 보고되었다. 본 연구에서는 장기 사용레일에 대한 실내피로시험을 수행하였고, 파괴확률 50%에서의 장기 사용레일의 잔존수명을 표현한 S-N 선도는 적은 실험데이터에 대한 가중치 확률 해석기법을 사용하여 도출하였다. 여기서 피로시험에 사용된 레일들이 누적통과톤수가 서로 다르기 때문에 누적통과톤수를 평균하여 반복횟수를 수정하였다. 또한, 레일표면요철 및 열차속도를 고려한 레일 저부 휨응력은 기존 연구결과 도출된 레일휨응력 예측식을 사용하여 장기 사용레일의 잔존수명을 평가하였다. 따라서 본 연구를 통해 도시철도에서 레일연마를 통한 레일관리가 이루어진다면 누적통과톤수에 의한 레일교체기준(약 8억톤)보다 약 2억톤이상 연장 사용이 가능하며, 피로한도 이하의 응력범위에 대한 피로시험결과를 바탕으로 레일의 피로수명을 평가하기 위해서는 수정마이너법칙보다는 피로한도 이상에서의 S-N선도 기울기의 1/2인 하이바크법칙을 적용하는 것이 합리적이라 판단되었다. As a result of recent research, it is reported that the periodic replacements criterion of rails is able to extend as grinding rail surface and using the continuous welded rail (CWR). In this study, we carried out fatigue tests on existing laid rails. Based on the test results, an S-N curve expressing the remaining life of laid rails at a fracture probability of 50% was obtained using weighted probit analysis suitable for small-sample fatigue data sets. As rails used for testing had different histories in terms of accumulated tonnage, the test data were corrected to average out the accumulated tonnage. We estimated the remaining service lives for laid rails on the urban railway using equations developed in the past to estimate rail base bending stress and that surface irregularities into consideration. Therefore, estimating the remaining service life of laid rails showed that the rail replacement period could be extended over 200 MGT, although it is necessary to remove longitudinal rail surface irregularities at welds by grinding. Also, the fatigue test results under fatigue limit, Haibach's rule appling half slope of S-N curve under the fatigue limit was considered more reasonable than modified Miner's rule for estimating rail fatigue life.

레일연마를 고려한 장대레일의 피로수명 평가

공선용,성덕룡,박용걸,Kong, Sun-Young,Sung, Deok-Yong,Park, Yong-Gul 대한토목학회 2015 대한토목학회논문집 Vol.35 No.5

본 연구에서는 국내 일반철도 새마을호 동력차 및 궤도조건을 고려한 차량/궤도 상호작용해석을 수행하였다. 레일표면요철에 따른 레일휨응력을 분석하였고, 레일 휨응력예측식을 도출하였다. 또한, 일반철도 레일강의 S-N선도를 이용한 피로해석을 수행하였다. 파괴확률에 따른 레일피로수명을 산정하였고, 레일연마에 따른 레일표면요철 제거 및 레일휨응력 저감효과를 고려한 레일피로수명 평가를 수행하였다. 따라서, 국내 일반철도에서 레일연마 시행방법에 따른 레일피로수명을 평가하여 제시하였다. In this study, vehicle/track interaction analysis by the Saemaul powered vehicle was carried out. The prediction equation for the bending stress of rail was estimated using the rail bending stress by the rail surface irregularities at welds. Also, the fatigue analysis using a S-N curve of welds in the conventional railway was carried out. We estimated the fatigue life of CWR by the fracture probability. By the rail grinding, the fatigue life of CWR was evaluated in consideration to reduce the rail bending stress through removing the rail surface irregularities. Therefore, it presented the fatigue life of CWR according to the rail grinding execution plan in the conventional railway.

서울지하철 4호선 R250m 인접구간 도시개발정비에 따른 궤도방진설계

공선용(Kong Sun-Yong),김상진(Kim Sang-Jin),양태경(Yang Tae-Kyung),백찬호(Baik Chan-Ho) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.7

The surroundings around subway are becoming more lively for project of CBD (an redevelopment project), however vibrations which are made through passing train cold spread buildings around. The structure-borne noise could be generated at the same time that makes people including developers and th citizens have negative viewpoint on railway. Especially, Seoul Metro 1-4 lines ar built alongside the road nearby houses and business district. That could make plenty of public resentments because of the structure-borne noise. Seoul Metro should make active alternative plans for their future urban environment projects which will be conducted. The case was Railway Facility which were conducted to minimize structure-borne noise from sharp curved track section (4 line, Sinyongsan~Ichon, R 250m). The section is adjacent to house district as near as 6.6m related with pusing international city project, the 4th urban environment project around international building, near Yongsan station. The interval of sleepers would be downsized in half with breaking existing case, and pad stiffness is reduced 4 ton from 10 ton. That makes structure-borne noise minimized because of vibrations are lowered about 19.1-23.0db. The structure above has remained for a year and a half from October, 2008, and had not any trouble to perform excellence with 80million ton rail accumulated tonnage.

현장측정을 통한 노후 레일의 피로수명 평가에 관한 연구

공선용(Kong Sun-Yong),성덕룡(Sung Deok-Yong),김준형(Kim Jun-Hyung),박용걸(Park Yong-Gul) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

It is essential to reduce track maintenance costs and to extend the periodic replacements of continuous welded rails based on accumulated passing tonnage. As recently train load decrease and rail joints wear down less, the periodic replacements of continuous welded rails can be extended. There are many kinds of rail damage like squat, head-check and corrugation. These can be taken nondestructive or naked eye test. So the periodic replacements of continuous welded rails based on accumulated passing tonnage were examine with focusing on a crack of rail bottom of continuous welded rail. Therefore, this study measure dynamic response of track by metro train load, it compute impact coefficient and track spring coefficient for estimating a condition of actual track system. Also, it is converted the measured stress waveform into stress frequency histogram by the rain-flow counting methods, and then the equivalence of stress is calculated. As apply s-n curve of a new welded rail, accumulated fatigue damage ratio of laid rail and remaining service lives is estimated. This study suggest a plan of the periodic replacements of continuous welded rails based on accumulated passing tonnage classified by the types of track system.

레일지지계수 및 축중 변화에 따른 B2S판넬의 최적두께 산정

공선용(Kong Sun-Yong),김상진(Kim Sang-Jin),백찬호(Baik Chan-Ho) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월

Most of Domestic railroads was composed of the ballast track that had an advantage of LCC (Life Cycle Cost) and it was constantly developed with the railroad materials such as a fastening components. Recently, it also has turning point to the concrete slab tracks that improve the driving stability. As the concrete tracks are planned, the Rail Level is regarded as an important factor on the construction expense. Although the Rail Level becomes lower than before that is to be stable enough for vehicle operating with technological development. Because of the B2S features that used a precast panel, estimation of its optimum thickness is also important factor for not only expense but also efficiency during mortar construction to the bottom layer of panel. This paper presents to calculate the optimum thickness of B2S panel according to various axle loads and rail support stiffness, and to evaluate the applicability. It also analyzes the effect from train loads to track by the 3D model, when the various rail support stiffness is applied for axle loads such as subway, light rail transit, railroad for convention line. As a result, it was evaluated that applicability of B2S slab track related to the conclusion for 2 types of railroads of other operating condition. And it should be used for the improvement of existing and construction railroads and tried to secure the basic data for structural safety and optimal track design.

서울메트로 1~4호선 고가역(창동역) 고체소음 저감 사례

공선용(Kong Sun-Yong),오희완(Oh Hee-Wan),김상진(Kim Sang-Jin) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

In the recent railway construction, the concrete slab track is highlighted as the maintenance-free track and the main stream is moving from ballasted track to concrete slab track. However, in spite of many merits of concrete slab track, the higher noise generated from the concrete slab track is a troublesome question to solve and, by this reason, many studies on noise reduction of concrete slab track are carried out. The railway noise can be classified into the reflection noise emitted from wheel/rail contact and the structure-borne noise transmitted through railway structures. In this presentation, we would like to introduce an example of the successful reduction of structure-borne noise at track retrofitting to maintenance-free concrete slab track in elevated Changdong Station which was built with ballasted track on Rahmen structure.

급곡선용 레일탄성체결장치를 사용한 생력화궤도 시공 사례

공선용(Kong Sun-Yong),김상진(Kim Sang-Jin) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-

SMSC(Seoul Metropolitan Subway Corporation) is substantially taking the core role of mass transit system in Seoul Metropolitan area. When it was built, the design had challenged to sharp curved tracks less than 250m radius considering the protection of buildings and cultural properties as well as the connection to ground roads. Such circumstances have required a certain extent of slack in track geometry and therefore led to the construction of ballasted track with wooden sleepers. However, the dynamic force from running on sharp curved track has caused the misalignment and abnormal failure of track geometry, and it has resulted in a frequent maintenance and repair works which require a lot of cost and manpower. In this paper, we present the construction case of maintenance-free track system by using of concrete sleeper and elastic rail fastening system to ensure the safety of both passengers and trains, and to contribute the effective maintenance for track facilities of SMSC.

지하철 3호선 동호철교 하로판형교 구간 콘크리트도상화개량 시공 사례

공선용(Kong Sun-Yong),이규천(Lee Gyu-Chon),김상진(Kim Sang-Jin) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-

In this report, we introduce the design criteria, construction case and performance of our track improvement project from ballasted track to concrete track on the example section of Dong-Ho Bridge (girder-plate type bridge) in Seoul Metro Line No. 3, after monitoring 3 years which is from Dec. 2002. 15-year-old Dong-Ho Bridge"s ballast was crushed, worn away, reduced track absorption, had draining problems from the crushed ballast, and corrosion was progressing in steel bridge because the waterproof underneath track was partially damaged. So, we applied changing the track on bridge area from ballasted to concrete in order to keep the track watertight and improve durability of bridge by reducing its weight. This investigation is based on the design criteria and construction case of the concrete track on the girder-type bridge in operating line. We explain the main design, materials, and other performance results in detail and hope it to be helpful for the track improvement in operating line.

B2S궤도 적용에 따른 철도교량의 동적안정성 검토

공선용(Kong Sun-Yong),김상진(Kim Sang-Jin),백찬호(Baik Chan-Ho) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월

This paper presents an analytic study for replacement of the ballast track in existing subway bridge by the Precast slab panel(B2S) track. To evaluate the dynamic responses on application of B2S track, the time history analysis with the 3D modeling. A total of two models, which were one ballast track bridge and B2S track bridge, were used in the FE analysis. The results of this study show that the dynamic displacement and acceleration of the B2S track bridge were significantly reduced for a higher train speed, compared to the ballast track bridge. Also, the replacement of the ballast track bridge in existing subway bridge by the B2S track increased the structural safety of bridge and ensured sufficient dynamic stability and serviceability. As a result, the servicing subway bridge with B2S track system has need of the reasonable measures which could be reducing the static and dynamic response and improving the performance.

콘크리트 궤도의 최적 탄성에 관한 연구

공선용(Kong Sun-Yong),김상진(Kim Sang-JIn) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

In recent railway construction, the concrete slab track is getting highlighted as main stream in track type. However, it is the fact that there are different opinions in selection of the optimized spring coefficient of elastic pad. In this study, the performance of vibration reduction in different stiffness of rail pad for ballasted track was compared, and the changes in characteristics, such as static/dynamic deflection of components, vibration acceleration, insertion loss etc., were analysed by using ISI Program for various types of rail fastening system used in concrete slab track. It was concluded that the fastening system with softer pads has shown the better performance of vibration reduction in concrete slab track and the optimized static stiffness has been calculated to 21.1kN/㎜ for conventional railways, 17.6kN/㎜ for high-speed railways and 17.8kN/㎜ for subways.