• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2006년도 추계학술대회 논문집
• /
• pp.407-413
• /
• 2006

Railways are very important to get stability of railway structure as transportation system carrying a lot of passengers and freight. These days the construction of underground railway crossing such as expansion of new roads, construction of subway and gas pipe is increasing because of economic and social development. But these kinds of construction didn't take into account Cost-benefit analysis of railway which has the most important aspects of railway safety, so the results of construction didn't get a good evaluation. This study adapt Cost-benefit analysis to evaluate the economic validity of underground railway crossing. This study adjust about Cost-benefit analysis of railway part, and analyze the new method and technology of underground railway crossing constructed by Korean National Railroad and Railway Network Authority. Also this study divide between high frequency line and low frequency lineusing B/C, NPV, and IRR analysis. After analysis, B/C ratio method is the most suitable method among B/C, NPV, and IRR analysis method. Therefore this study can express economic benefit quantitatively and decrease the cost by adapting Cost-benefit analysis, and can clearly express the construction feasibility and investment effects of construction of underground railway crossing method.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.595-600
• /
• 2007

Greater expansion and more frequent operation of the railroad transportation system anticipated due to its characteristics including low cost, safety and mass transportation. Recently, effects on the railway structures due to expansion of newly constructed road, construction of subway, city gas pipeline, communication network, electric power network and construction of other railway underground crossing in accordance with urban planning and organization has influenced safe operation of trains. Accordingly, standard for selection of construction method that will enable construction of more economical and rational subway underground crossing structures by preventing problems occurring at the time of above construction works and accidents in safe operation of trains due to construction in advance is definitively necessary. Although there are numerous construction methods that can be applied at the time of construction of railway underground crossing, there are much difficulties in selection of appropriate construction method that considers characteristics of each construction method on non-excavation type construction method, train operation plan of number of operational routes and on-site circumstances. Therefore, this research aims to present rational standard for selection of construction method for such, and standard for slowdown speed and interception of train when passing the areas of slowdown in sectors under construction.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2001년도 추계학술대회 논문집
• /
• pp.546-551
• /
• 2001

We analysed the affection to subgrade that railway underground crossing construction make with studying displacement of subgrade of each construction methods and processing of Front jacking method and Pipe roof method with already-measured data(during the construction) and additionally-measured field test data in railway underground crossing construction. We measured vertical and horizontal displacement at two construction places of front jacking method and pipe roof method each, and we analysed the results of the measurement at each stage of construction to applied to the excution of construction.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.2439-2449
• /
• 2011

Existing grade crossings between railway and roadway area gradually changed to grade separation systems by the law. In the case of new roadway construction which crosses railways, it shall be grade separation system in principle. With the railway underground crossing method, many practices have been developed which can minimize rail displacements and avoid rail release. With these methods, the effects to the train can be reduced. The underground crossing methods can be identified as open-cut methods and non open-cut methods. The open-cut methods include temporary support methods and special rail construction methods. Also the non open-cut methods includes pipe roof methods, front jacking methods, messer shield methods, NTR methods and JES methods. Among these, the most suitable method is applied considering safety, economy, class of each rail system (train passing frequency and velocity), etc. In the non open-cut methods, the cost and duration shall be increased to keep existing rail system during construction. In the open-cut methods which use plate girders, the rail speed shall be restricted due to the displacement and vibration of the girder. In this study new grade separation methods were developed. With this method, the safety during construction can be increased. This method refines temporary support methods, but pc slab girder with huge stiffness is applied instead of plate girders. With this method, the rail displacement can be reduced and higher safety can be obtained during construction. Also construction cost and duration can be minimized because the temporary work and the overburden soil depth can be reduced.

• International Journal of Railway
• /
• 제6권2호
• /
• pp.69-77
• /
• 2013

In this study, numerical analysis and model experiments were conducted to analyze behavioral characteristics acting on the track roadbed with excavation through steel pipe injection, a non-exclusive method of crossing construction under railroad as primary target. In model experiments that simulate injection excavation behaviors with an increase in the depth of soil cover, the upper displacement was measured by construction of the first and the second pipes in order to predict actual behaviors, and the behavior characteristics were verified through numerical analysis. The investigation results showed that surface displacement was smaller under the condition of higher soil cover. In the case of injecting two pipes, when the first pipe was injected, deformation of the surface increased linearly in both settlement and uplift experiments. However, when the second pipe was injected, the amount of change was found to be very small due to the relaxation and plastic zones around the first pipe. In addition, the results of numerical analysis on the same cross section with the model experiment found that the results of investigation into settlement ratio and volume loss were in very good agreement with those obtained by the model experiment.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.895-902
• /
• 2010

The method in a bid to make better use of limited urban space amidst increasingly expanding urban area have been attempted in various ways. Efficient using underground space is one of the examples. The pipe roof and excavation for underground crossing implemented in this study was the part of evaluation of such attempt. However, the pipe roof method for underground crossing may cause the ground surface to be uplifted or settled down, having effect on structure above the ground. Thus in this study, a laboratory model test designed to evaluate the effect on surface during implementing pipe roof and excavation was carried out. The ground displacement during pipe roof advancing and excavation is usually occurred in a radial shape but as the study focused on trackbed, the evaluation included ground settlement only. Thus, appropriately-scaled model was selected considering domestic geological characteristics and operation characteristics of traditional and high-speed rail trains and the qualitative evaluation of displacement was carried out with a certain ground loss depending on excavation after categorizing trackbed settlement pattern depending on depth of top soil.

• Geomechanics and Engineering
• /
• 제11권1호
• /
• pp.117-139
• /
• 2016

Previous studies for soil movements induced by tunneling have primarily focused on the free soil displacements. However, the stiffness of existing structures is expected to alter tunneling-induced ground movements, the sheltering influences for underground structures should be included. Furthermore, minimal attention has been given to the settings for the shield machine's operation parameters during the process of tunnels crossing above and below existing tunnels. Based on the Shanghai railway project, the soil movements induced by an earth pressure balance (EPB) shield considering the sheltering effects of existing tunnels are presented by the simplified theoretical method, the three-dimensional finite element (3D FE) simulation method, and the in-situ monitoring method. The deformation prediction of existing tunnels during complex traversing process is also presented. In addition, the deformation controlling safety measurements are carried out simultaneously to obtain the settings for the shield propulsion parameters, including earth pressure for cutting open, synchronized grouting, propulsion speed, and cutter head torque. It appears that the sheltering effects of underground structures have a great influence on ground movements caused by tunneling. The error obtained by the previous simplified methods based on the free soil displacements cannot be dismissed when encountering many existing structures.

• 한국터널지하공간학회 논문집
• /
• 제20권3호
• /
• pp.543-560
• /
• 2018

도심지 지하공간의 개발과 운행선 하부를 저토피로 입체 교차화하는 시설 증가에 따라 비개착식 공법의 수요는 점차 증가추세에 있으나 대다수의 공법은 중대구경 강관을 압입하여 루프를 형성하고 내부를 굴착하는 파이프루프(Pipe roof) 계열의 공법이 주로 적용되고 있다. 강관 압입 시 발생되는 이완영역 및 하중은 여러 인자의 영향을 받게 되나 가장 큰 요소는 압입하는 강관의 크기에 좌우되며 이는 강관 루프 내 지중구조물에 작용하는 하중의 크기로 볼 수 있다. 지반의 교란 및 이완하중 발생을 최소화시키기 위해 개발된 SEM공법(Super Equilibrium Method)은 기존의 중대구경 강관 대신 ${\Phi}114mm$ 내외의 소구경 강관을 사용한다. 이 소구경 강관을 SEM파일로 명명하였으며 강관의 선 압입 및 그라우팅 보강을 실시한 후 지반의 침하나 융기 없이 지반 내 횡단구조물을 유압잭을 이용하여 압입하게 된다. 이와 같이 SEM공법의 구성 중 지보역할을 하는 SEM파일은 선단부 굴착 시 지반의 붕락을 방지하고 상재하중을 지지하기 위한 길이 5 m 내외의 Fore poling 파일이며 이 파일의 배치간격, 시공연장, 부재의 강성 등을 산정하기 위해서는 이완영역의 적절한 산정이 필수적이다. 본 논문은 SEM공법의 최적설계를 위하여 SEM파일 압입 시 발생되는 이완하중 산정 값을 비교분석하였다. 이완영역 산정에 근거한 주요 이론식 및 경험식들의 영향인자를 고려하여 분석하고 FEM analysis (유한요소 해석)를 수행하여 SEM파일에 적합한 이완하중 산정을 검토하였다. 또한 실제 SEM파일 압입 및 굴착 시 발생되는 지반이완을 확인하기 위해 강관압입 축소모형실험을 수행하였으며 토피고/강관(H/D)에 따른 지표침하 및 지반이완을 정량적으로 검토하였다.