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지광습(Goangseup Zi),이승정(Seungjung Lee),장승엽(Seungyup Jang) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.7
We proposed a design procedure for Korean Precast Slab Track system. Korean Precast Slab Track system cannot use the same design procedure to German slab track system because of different shapes and some problems. We identified the problems of German slab track design system that cannot simulate effects of loads. This proposed procedure is implemented for the commercial software of ABAQUS. Using this procedure, one can consider uncombined effects between slab panel and hydraulic sub base, effect of close sleepers.
GPR 분석을 위한 자갈궤도 자갈의 감쇄특성을 이용한 이득함수 개발
신지훈(Jihoon Shin),최영태(Yeongtae Choi),장승엽(SeungYup Jang) 한국지반환경공학회 2017 한국지반환경공학회논문집 Vol.18 No.4
자갈궤도는 100여년 이상 전세계적으로 널리 사용되는 궤도구조로 저렴한 초기 건설비용, 유연한 유지보수와 진동 및 소음의 저감효과가 있지만, 열차운행에 따라서 지속적인 침하가 발생하는 단점이 있다. 이로 인해 지속적인 유지보수가 필요하며, 최근 열차의 속도, 용량, 중량의 증가로 유지보수비용이 증가하고 있는 실정이다. 파울링(fouling)은 노반 세립분이나 자갈입자가 파쇄되면서 발생한 세립분이 자갈 사이의 공극을 메우는 현상으로 배수가 나빠지고, 자갈궤도의 침하를 가속화시키는 등 자갈도상의 열화의 주원인으로 지목되고 있다. 본 논문에서는 GPR(Ground Penetrating Radar)을 이용하여, 도상의 상태를 평가 할 수 있는 분석방법을 제안하였다. 경험에 의존하는 기존의 분석기법을 대신하여, 고속선에 사용되는 자갈의 감쇠 특성을 반영한 이득함수(gain function)를 제안하였다. 실내 박스 실험과 실모형 실험을 통해 제안한 이득함수로 증폭한 GPR신호에 힐버트 변환을 추가로 적용하여 자갈층과 노반층에서 반사된 신호의 세기변화를 깊이에 따라 계산하였다. 이로부터 신호의 세기가 비교적 크게 변화하는 곳을 파울링층과 노반층의 경계로 구분할 수 있었다. 다만 현장적용을 위해서는 침목의 영향을 분리하고 전자기파 분산특성 등에 대한 추가 연구가 필요할 것으로 사료된다. Ballasted track has been used as track system for more than 100 years. Ballasted track has advantages of low construction cost, flexible maintenance, low noise and vibration, and so on. However, ballasted track leads to continuous settlement which causes maintenance. Recently, increase in speed, traffic volume, and weight of train requires more frequent maintenance. Fouling, well-known phenomenon of accumulation of fine materials due to intrusion of subgrade and breakage of ballast materials, expedites the settlement (i.e., irregular settlement) of track. Ground Penetrating Radar (GPR) can be one of non-destructive tools that can evaluate fouling level of ballast. In this paper, a gain function based on the attenuation characteristics of ballast material is suggested in conjunction with Hilbert transform. Lab box tests and full-scale tests indicate that the suggested method reasonably classifies clean, fouled layers, and subgrade. However, additional study to eliminate effect of sleeper and to include the scattering features of the electromagnetic wave in ballast voids should be required in order to enhance the accuracy.
최원석(Choi, Wonseok),이희영(Lee, Heeyoung),이일화(Lee, Illwha),장승엽(Jang, SeungYup),정원석(Chung, Wonseok) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.1
급속경화궤도는 기존의 자갈도상궤도를 콘크리트궤도로 대체하는 방식으로 유지⋅보수비용을 절감할 수 있는 장점을 갖고 있다. 급속경화궤도를 고속철도에 적용할 경우에는 열차하중의 증가로 인해 콘크리트에 응력이 과도하게 발생할 위험이 있다. 따라서 교량상 급속경화궤도를 적용하기 위해서는 레일과 급속경화궤도 슬래브의 거동에 대한 분석이 필요하다. 본논문에서는 유한요소해석을 통해 교량상 급속경화궤도의 레일 및 슬래브의 거동을 분석하고, 급속경화궤도 슬래브의 적합한 앵커수, 앵커설치위치, 급속경화궤도의 시공길이를 산정하는 모델을 제시한다. The existing ballasted track has problems including riding quality degradation due to disorder of track and increasing maintenance cost. To solve the aforementioned problem, Fast Hardening Track (FHT) has been developed for replacing the ballasted track. When applied to the FHT high-speed rail, the slab has a risk of stress that occurs on a concrete slab as the train load increases. Therefore, The analysis of the behavior of rails and slabs are required to apply to a bridge. This study suggests a number of appropriate anchors and anchors installation location, construction length in the FHT.
한병찬(Han ByungChan),김재환(Kim JaeHwan),임승찬(Lim SeungChan),권영진(Kwan YoungJin),임남형(Lim NamHyoung),이진옥(Lee JinOk),장승엽(Jang SeungYup) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-
The synthetic fibers such as polyvilyl-alcohol(PVA) fiber are poised as a low cost alternative for reinforcement in structural applications. It has been reported that synthetic fiber in cement composites can control restrained tensile stresses and cracks and increase toughness, resistance to impact, corrosion, fatigue and durability. High performance fiber reinforced cementitious composite(HPFRCC) shows ultra high ductile behavior in the hardened state, because of the fiber bridging properties. In this study, it was proposed a direct tensile testing machine(DTTM) to be simple and to be applied to HPFRCC, and examined the tensile properties of HPFRCC by this machine. As a results, it was confirmed that a direct tensile test of HPFRCC could be certainly carried out DTTM to be developed in this study. Also, tensile strength and yield strength of HPFRCC were similar regardless of specimens thickness. And, all specimens revealed the stable strain-hardening behavior and multiple cracking in flexible and tensile loads. But, deviation of strain at ultimate tensile strength increased with the increase of specimen thickness.
한병찬(Han ByungChan),김재환(Kim JaeHwan),임승찬(Lim SeungChan),권영진(Kwan YoungJin),임남형(Lim NamHyoung),이진옥(Lee JinOk),장승엽(Jang SeungYup) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-
High performance fiber reinforced cement composite(mortar) shows ultra high ductile behavior in the hardened state, because of the fiber bridging properties. Therefore, a variety of experiments have being performed to access the performance of the materials recently. In this study, a flexural fatigue test was carried out to investigate flexural fatigue behavior and provide basic data for fatigue design. Based on the flexural fatigue test, the fatigue safety of the high performance fiber reinforced cement mortar specimens was estimated. For the fatigue test, 10x10x40cm specimens were designed. A static flexural load test was also performed before the fatigue test to analyze the structural behavior of the specimens. The initiation of fatigue cracks in the specimens could be detected through the history of displacement range. Fatigue limit was predicted Weibull distribution using S-N relationship, and a satisfactory result was obtained.