콘크리트 슬래브궤도의 휨강성 평가를 위한 비파괴 탄성파 기법의 개발

조미라(Cho Mi-Ra),조성호(Joh Sung-Ho),이일화(Lee Il-Wha) 대한토목학회 2008 대한토목학회논문집 D Vol.28 No.6D

최근 고속전철의 자갈도상에 대한 대안으로 콘크리트 슬래브궤도가 도입되어 고속전철 신규노선에 시공되고 있다. 콘크리트 슬래브궤도는 자갈 상에 비해 내구성, 유지관리 측면에서의 경제성, 열치운행의 안정성 등의 측면에서 우위에 있지만, 우수 및 지하수로 인한 노반강성의 저하, 연약한 원지반의 침하 등으로 인한 슬래브궤도의 처짐은 열차안정성에 치명적인 결함이 된다. 본 연구에서는 슬래브궤도의 처짐 지표로서 슬래브궤도의 휨강성을 설정하고 슬래브궤도의 휨강성을 2차원 영상으로 표현할 수 있는 FRACTAL (Flexural-Rigidity Assessment of Concrete Tracks by Antisymmetric Lamb Waves) 기법이라는 비파괴 탄성파 기법을 제안하였다. 이론적 근거 확보를 위하여 콘크리트 슬래브궤도에서의 탄성파 시험을 수치해석적으로 모사하여 영향인자 연구를 수행하였고, FRACTAL 기법의 적용성 평가를 위하여 실제 고속전철 슬래브궤도에 적용하여 보았다. 그리고 FRACTAL 시험측선과 통일 측선에서 Impulse-Response 기법과 인접지반에서 전기비저항시험을 수행하여, FRACTAL 기법의 신뢰성을 검증하였다. Recently, concrete tracks are introduced into high-speed railroads as an alternative to ballast tracks. Concrete tracks are superior to ballast tracks in the aspect of durability, maintenance and safety. However, deteriorated stiffness of railroad bed and settlement of soft ground induced by trapped or seepage water lead to problems in safety of train operation. In this research, flexural rigidity of concrete tracks was employed as an index of track displacement and a new seismic technique called FRACTAL (Flexural-Rigidity Assessment of Concrete Tracks by Antisymmetric Lamb Waves) method was proposed to delineate flexural rigidity of concrete tracks in a 2-D image. In this paper, to establish theoretical background, parametric research was performed using numerical simulations of stress-wave tests at concrete tracks. Feasibility of the FRACTAL technique was proved at a real concrete track for Korean high-speed trains. Validity of the FRACTAL technique was also verified by comparing the results of impulse-response tests performed at the same measurement array and the results of DC resistivity survey performed at a shoulder nearby the track.

자갈궤도와 콘크리트궤도에서의 하중재하에 따른 노반거동 비교

최찬용(Choi Chan-Yong),이성혁(Lee Sung-Heok),엄기영(Eum Ki-Young) 한국토목섬유학회 2010 한국지반신소재학회 논문집 Vol.9 No.3

국내에 적용하고 있는 궤도시스템은 크게 자갈궤도와 콘크리트궤도로 구분할 수 있다. 본 논문에서는 콘크리트궤도와 자갈궤도의 노반 거동현상을 실험적으로 비교하였다. 실 대형 실험결과 하중 분산은 자갈궤도의 경우 연성포장구조, 콘크리트궤도는 강성포장구조의 형태로 하중이 분산되었으며 하중배분율은 약 30%:20%:15%로 자갈궤도보다 폭 넓게 분산되었다. 열차하중에 대한 노반에서 발생된 토압은 약 30㎪ 이내로 기존 실차주행시험결과와 유사한 결과이며 자갈궤도에 비해 약 4배 정도 작게 발생하였다. 또한 반복하중에 대한 콘크리트궤도의 지중입자속도는 약 0.3㎝/sec 이내로 자갈궤도보다 8배 정도 작게 측정되었다. The track systems installed in Korea railway consist of two types on ballasted track or ballastless track. In this study, it was compared with difference of the behaviors at roadbed with cyclic loading through full scale model test. From the results of model tests, loading distribution ratio of the concrete slab track become more widely distributed than ballasted track, and loading distribution ratio at concrete track was about 30:20:15. The concrete slab track is likely to behavior of the rigid plate, while ballasted track is such as flexible pavement. The vertical stresses of upper roadbed with traffic cyclic loading in concrete track were measured about 30 ㎪ or less. It was a scene very similar to the results of the field train running test. The vertical stress at concrete track was occurred approximately 4 times smaller than ballasted track. Also, the soil velocities with cyclic loading at the slab track were occurred about 0.3 ㎝/sec or less, its 8 times smaller than ballasted track.

콘크리트 궤도 균열 및 유지관리 방법에 대한 연구

이종태(Lee Jong Tae),강보순(Kang Bo Soon) 한국철도학회 2015 한국철도학회 학술발표대회논문집 Vol.2015 No.10

최근 철도가 고속화가 되면서 높은 안전성과 유지보수의 노력과 비용 절감을 위해 국내외적으로 콘크리트궤도가 증가되고 있는 추세이다. 고속철도 경우에는 콘크리트궤도가 자갈도상궤도에 비해 더 효율적이라고 평가되고 있으나 현장타설 콘크리트궤도는 도상의 균열, 침목의 균열, 도상과 침목의 분리 등 이 발생 될수 있고 현장타설 콘크리트궤도 같은 경우에는 기준이 명확하게 제시되어 있으나 사전제작식 콘크리트궤도 같은 경우에는 충전재 탈락, 패널 과충전재 사이의 간극등이 발생되고 있지만 아직 유지관리 기준이 확립되어 있지 않다. 따라서 콘크리트궤도의 문제점을 파악하고 현장타설 콘크리트궤도와 사전제작식 콘크리트의 관리에 있어서 기준 값을 초과 되지 않는 범위를 유지 하기 위해 국내기준과 해외기준을 비교, 적합한 기준을 찾고 콘크리트 궤도를 더 안전하게 유지하고 보수하는 방법을 고찰하고자 한다. Recently, railway steps into a high-speed era. Under the consideration of improving safety and decreasing repairing cost, our country pave concrete track to follow the world trend. Concrete track enjoy higher rank than gravel ballastless track. In addition, on site casting concrete track concrete track also has roadbed cracks, sleeper cracks and others when roadbed and sleeper separating. also Precast concrete traks has filler shed and the gap between panel and filler. However, the situation of on-site casting concrete track is confirmed but Precast concret track is not. Therefore, the study of concrete track in and outside of country focuses on understanding and managing on-site casting and Precast concrete track, compare state with national standard, to find a suitable standard to maintain and renovate concrete track in a safety way and on the study on it.

고속철도 콘크리트 궤도상 토공노반의 장기거동 특성 연구

최찬용(Chan-Yong Choi),정재현(Jae-Hyun Jung) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.4

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. 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 valuation 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.

광폭침목형 아스팔트콘크리트 궤도의 열차 주행 시 거동 분석

이성혁(Seong-Hyeok Lee),배영훈(Young-Hoon Bae),최영태(Yeong-Tae Choi),한두섭(Doo-Seop Han),정인균(In-Gyun Jeong) 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05

자갈궤도와 콘크리트 궤도의 장점을 결합하고 단점을 상호 보완한 신개념 궤도시스템인 아스팔트 콘크리트 궤도에 대한 연구를 수년간 수행하여 왔다. 그 동안의 연구결과를 바탕으로 국내 최초로 아스팔트콘크리트 궤도를 영업선에 시험 부설하여 현장설치 시험을 진행하고 있다. 본 연구에서는 시험 부설된 광폭침목형 아스팔트콘크리트 궤도에 대해 열차 주행 시 측정된 윤중, 횡압, 레일 저부 응력, 레일 및 침목의 수직변위를 이용하여 광폭 침목형 아스팔트콘크리트 궤도의 거동 특성을 분석하였으며, 분석 결과 광폭 침목형 아스팔트 콘크리트 궤도는 궤도 안전성을 만족하기 위한 요구 사항을 만족하고 있는 것을 확인하였다. Asphalt concrete track has been studied for a few years, which is a new concept railway track that combines the advantage between ballasted track and concrete track. Based on the results of the study, asphalt concrete track was inceptively constructed on the commercial line in Korea and field test is in progress. In this study, wheel load, lateral load, stress of rail bottom surface, vertical displacement of rail and wide sleeper were measured in wide sleeper type asphalt concrete track during train operation. The behavior of wide sleeper type asphalt concrete track was analyzed by the measured results. As a result of the analysis, it was confirmed that wide sleeper type asphalt concrete track was fitted to the requirements for track safety and stability.

현장타설 콘크리트궤도 시공 중 초기균열 저감을 위한 연구

김만철(Man-Cheol Kim),배영훈(Young-Hoon Bae),표석훈(Sukhoon Pyo),김재학(Jae-Hak Kim),신순호,김인섭(In-Sup Kim),서흥석(Heong-Sok Seo) 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05

콘크리트궤도의 균열은 장기적인 내구성을 저하시키고 유지보수 시간 및 비용을 증가시키며, 철도 안전에 대한 사회적 논란을 유발시킬 수 있다. 본 논문은 현장타설 콘크리트궤도 양생 중에 강재 임시레일의 온도변화에 의해 유발되는 균열 저감 대책을 연구하였다. 이를 위해서 낮은 열팽창계수를 갖는 복합소재 임시레일 및 타설 직후 콘크리트 궤도를 두꺼운 포장재로 덮는 방법을 이용한 현장시험을 실시하여 초기 균열 발생 현황을 분석하였다. 그 결과 콘크리트궤도 양생 중 발생하는 초기 균열을 방지하기 위해서는 콘크리트 타설 직후 콘크리트궤도를 두꺼운 포장재를 덮어 레일의 온도변화를 최소화 하고, 가능한 이른 시간 내 임시레일을 해체하거나 기온변화가 없는 시기에 콘크리트를 타설하는 것이 콘크리트궤도 품질에 효과적인 요소임을 알 수 있었다. Cracks in concrete slab track have reduced long-term durability and increased the maintenance time and cost, and invoked the social controversy about railway safety. In this study, effective countermeasures are investigated to reduce cracks in concrete slab track caused by the temperature change of the temporary rail made from steel during on-site curing of concrete. The effectiveness to reduce the early age cracking is evaluated by adopting alternative methods: using temporary rails made from composite materials with low thermal expansion coefficient, and covering concrete slab track with thick packing sheets immediately after the casting of concrete. It is revealed from this research that efficient methods to reduce early age concrete cracking in concrete slab track are 1) minimize the temperature changes of rails by covering concrete slab track with thick packing sheets right after the casting of concrete, 2) disassemble of the temporary rails as soon as possible, and 3) cast concrete while temperature changes are insignificant.

장대레일 부설을 위한 궤도선형 설계기준의 콘크리트 궤도 적용성 평가

이형덕(Hyeoung-Deok Lee),송종걸(Jong Keol Song),윤기용(Ki Yong Yoon),문지호(Jiho Moon) 한국방재학회 2022 한국방재학회논문집 Vol.22 No.6

국내 KR code에 명시된 장대레일 설치 시 요구되는 궤도선형 조건은 자갈궤도의 경우 타당한 것으로 보여지나 자갈궤도에 비하여 훨씬 큰 좌굴 저항 성능을 갖는 콘크리트 궤도에 적용성은 명확하지 않다. 특히 도심지의 경우 장대화가 필요하나 KR code의 장대레일 부설조건을 만족하지 못하는 경우도 있으므로 콘크리트 궤도에 대하여 평가해 볼 필요가 있다. 본 연구에서는 이러한 점에 초점을 맞추어 연구를 수행하였다. 먼저 문헌조사를 통하여 KR code의 장대레일 부설을 위한 궤도 선형조건의 근거를 파악하였으며 이후 궤도좌굴 해석을 통하여 KR code 내 평면 및 종곡선 반경 조건에 대하여 콘크리트 궤도 적용성을 검토하였다. 검토 결과, KR code 규정 적용 시 특별한 보강 없이 콘크리트 궤도에 장대레일을 부설할 수 있는 것으로 나타났다. In the KR code, the track alignment limitations for CWR installation are specified. These limitations appear reasonable for ballasted tracks. However, its application to the concrete slab track is doubtful because the concrete slab track has a much higher buckling resistance than the ballasted track. In addition, sometimes the track alignment cannot satisfy the KR code limitations in urban areas. Therefore, the track alignment limitations for the CWR in the KR code should be evaluated for the concrete slab track. In this study, the focus was on assessing the applicability of track alignment limitations for CWR installation in the KR code for a concrete slab track. First, a literature review was conducted to identify the basis of KR codes. Subsequently, a series of track stability analyses were performed to evaluate the applicability of the horizontal and vertical curves in the KR code to the concrete slab track. The results indicated that CWR can be installed on a concrete slab track without special limitations for the curve ranges specified in the KR code.

철도에서의 다공성 폴리프로필렌 폴리머 콘크리트 슬래브 적용 타당성 분석

탁준영(J. Y. Tak),서인수(I. S. Suh) 한국도시철도학회 2014 한국도시철도학회논문집 Vol.2 No.1

In railway systems, tracks are installed to allow safer operation and distribute passed load on rail. Concrete slab tracks are being more utilized as railroad cars are developed to have higher speed performances when compared to Ballasted tracks. However, there are some disadvantages when it comes to noise reduction when compared to Ballasted tracks. In order to reduce those disadvantages, Concrete slab tracks have been continuously conducted in order to reduce noise and vibration but are still currently insufficient for commercialization. In this paper, Pervious concrete applying at the vehicle road field for reducing noise will be introduced and evaluated that can be applied into concrete slab track in railway field. Furthermore, the application of polypropylene polymer(PP) reinforced Pervious concrete slab track, its intensity of the absorption, and its feasibility of application has been researched.

Experimental investigation on the application of quick-hardening mortar for converting railway ballasted track to concrete track on operating line

Lee, Il-Wha,Pyo, Sukhoon Elsevier BV 2017 Construction and Building Materials Vol.133 No.-

<P><B>Abstract</B></P> <P>The ballasted track system has been widely adopted on conventional railways due to its ease of construction, but its key shortcoming is its need for frequent maintenance. In recent years, with the growing demand for railway vehicles capable of higher speeds and capacities, the concrete track is becoming more popular due to its high rigidity and relatively low maintenance. A fast converting technology was developed in this study to transform the existing ballasted tracks into concrete tracks using the developed quick-hardening mortar, which has high fluidity and strength development at an early stage, such that it could minimize the interruption of train operation. To assess the applicability of the developed mortar in the field, durability, fluidity and strength development of the mortar were characterized. The developed quick-hardening mortar was applied to a 52m-long existing ballasted track of an operating line, and structural stabilities under moving train loads were evaluated. Experimental results showed that the track conversion was successful with the quick-hardening mortar, and the concrete structures proved to have excellent performance compared to the existing ballasted track.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Converting technology developed to transform the existing ballasted tracks into concrete tracks. </LI> <LI> A quick-hardening cement mortar was developed that meets the functional requirements. </LI> <LI> Quick-hardening mortar was applied to a 52m-long existing ballasted track of an operating line. </LI> <LI> Running stability of the train on the converted track was evaluated. </LI> </UL> </P>

콘크리트 슬래브궤도에서 레일과 철근 사이의 결합계수에 대한 연구

김민석(Kim Min-Seok),이상혁(Lee Sang-Hyeok),권재욱(Kwon Jae-Wook),이종우(Lee Jong-Woo) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-

The system of the railway signaling using the track transmits the approved speed to the location of a train and it. Referring to the way of transmitting train control information, there are the one transmitting it to the on-board system of a train using the direct track, the another transmitting it establishing an instrument, and the other transmitting an instrument by a railway track. The one is the method using the direct track as a conductor for composing the part of the track and attaining the information controlling a train by transmitting a signal to the track. It is used for the high-speed railway and the subway. The method using the track attains information by transmitting it to returned information, and the on-board system of a train attains it by magnetic coupling. Because many reinforcing bars on the concrete slab track are used, interaction between a rail and a reinforcing bar that is not produced on ballast track is made. Due to the interaction, the electric characteristic of rail is changed. In the current paper, we numerically computed the coupling coefficient between the rail and the reinforcing bar based on the concrete slab track throughout the model related to the rail and the reinforcing bar using the concrete slab track that is used in the second interval of the Gyeongbu high-speed railway, and we defined the coupling coefficient not changed in the electric characteristic of rail in the condition that there is no interaction between the rail and the reinforcing bar.