• 로봇학회논문지
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• 제17권2호
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• pp.216-220
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• 2022

This paper proposes an inspection robot that can operate on a single square rail. Various inspection robots have been developed to identify emergency situations in industrial environments, such as those involving fires or individuals with cardiac arrest. Because the robots must operate in wide areas and long tunnels, they are designed to move along a rail installed on the ceiling. Double rail track are typically used to ensure the stability of robot movement. However, the cost for installing a double rail track is nearly two times that for a single rail track. Moreover, it is challenging to install double rail tracks while ensuring the same curvature and interval between the two rails. Therefore, in this study, an inspection robot that operate on a single square rail track is developed. To ensure stable movement in the longitudinal and lateral directions, two passive guide parts are used, and the main active wheel is allowed to move on the upper side of the square rail. The prototype was manufactured, and experiments were performed for different robot velocities.

• 한국터널지하공간학회 논문집
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• 제21권6호
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• pp.749-762
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• 2019

최근 들어 대도시의 교통난 해소 및 녹지공간 확보를 위해서 도로의 지하화가 추진되고 있으며, 대형차 혼입률이 낮기 때문에 소형차 전용 도로터널로 계획되거나 건설되고 있다. 또한, 도시에 건설되고 있는 터널은 간선도로의 기능을 수행하기 위해서 장대화되는 추세이다. 따라서 환기시스템의 용량이 증대하고 다양한 환기방식이 요구되고 있으며, 환기기 운전비용 등 터널준공 후, 유지관리의 중요성이 부각되게 되었다. 따라서 환기기 소비전력의 절감을 위한 운전단계의 최적화나 환기기 운전제어로직에 대한 연구의 필요성이 증대하고 있는 실정이다. 본 연구에서는 소형차 전용도로 터널에 ① 제트팬방식과 조합환기방식, ② 제트팬 + 공기정화방식, ③ 제트팬 + 수직갱방식, ④ 제트팬 + 급기반횡류환기방식을 적용하여 에너지 절약적인 환기기 운전을 실현하기 위해서 운전단계 및 제어로직 최적화 방안의 필요성에 대한 연구를 수행하였다. 연구의 결과로 조합환기방식의 터널의 경우, 다양한 운전조합이 있을 수 있으며, 발생되는 환기량이 동일할 지라도 운전조합에 따라 소요동력이 크게 차이가 나며, 일반적으로 수행하고 있는 제트팬 우선 운전방식보다는 축류팬을 우선 운전하는 것이 동력절감에 효과가 있는 것으로 나타났다.

• 한국지반공학회논문집
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• 제24권5호
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• pp.65-78
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• 2008

절토사면 및 천심도 터널의 경우 불연속면을 따른 블록의 미끄러짐 및 회전 등이 안정성에 큰 영향을 미친다. 절토사면이나 터널의 초기 설계 단계에서 안정성 검토를 위해 수치해석을 널리 사용하는데, 대부분의 상용화된 프로그램들은 연속체 해석에 기반을 두고 있다. 불연속면을 고려하여 연속체 해석을 수행할 수도 있으며, 절리를 포함한 암반자체의 강도를 감소시킴으로써 모사하는 것이 대표적인 방법이다. 또한, 연속체 해석방법인 Mohr-Coulomb 모델에 편재 절리모델 (ubiquitous joint model)을 적용함으로써 불연속면을 고려하는 방법이 있다. 절토사면의 수치해석시 주 입력치인 절리암반의 점착력, 마찰각, 탄성계수 등은 암반분류법(rock classification system)에 의한 경험식으로 도출할 수 있으며, 본 논문에서는 이 중 RMR 및 GSI 시스템에 의한 경험식을 통해 얻은 입력치를 실제 위험절토사면에 적용함으로써 두 시스템의 차이를 비교해 보고자 하였다. 또한 RMR 및 GSI 시스템으로 도출한 입력치에 편재절리모델을 혼합하여 적용함으로써 계측을 통해 얻은 변위량 및 변위양상과의 차이를 분석하였다. 분석 결과 GSI 시스템으로 도출한 입력치에 편재절리모델을 혼합하였을 경우의 수치해석결과가 실제현장의 변위량 및 변위양상과 가장 유사한 결과를 얻을 수 있음을 확인할 수 있었다.

• 한국안전학회지
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• 제32권3호
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• pp.130-135
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• 2017

This study deal with the traffic accident. The purpose of this study is to develop the accident density models reflecting the transportation and socioeconomic characteristics based on 230 zones of Korea. In this study, The models which are tested to be statistically significant are developed through multiple linear regression analysis. The main research results are as follows. First, in the transportation-based model, road length, avenue ratio, number of intersections and tunnels are analyzed to be positive to the model, however, school zone is analyzed to be negative to the model. Second, in the socioeconomic-based model, population density, transportation vulnerable ratio, children and truck ratio are analyzed to be positive to the model. Finally, in the integrated models, road ratio, population density, transportation vulnerable ratio, children ratio, truck ratio and number of companies are analyzed to be positive, however, school zone is analyzed to be negative to the model. This results could be expected to give good implications to accident-reduction policy-making.

• Computers and Concrete
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• 제11권1호
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• pp.51-61
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• 2013

This paper describes earthquake response of the Arhavi Highway Tunnel its geometrical properties, 3D finite element model and the linear time history analyses under a huge ground motion considering soil-structure interaction. The Arhavi Highway Tunnel is one of the tallest tunnels constructed in the Black Sea region of Turkey as part of the Coast Road Project. The tunnel has two tubes and each of them is about 1000 m tall. In the study, lineartime history analyses of the tunnel are performed applying north-south, east-west and up accelerations components of 1992 Erzincan, Turkey ground motion. In the time history analyses, Rayleigh damping coefficients are calculated using main natural frequency obtained from modal analysis. Element matrices are computed using the Gauss numerical integration technique. The Newmark method is used in the solution of the equation of motion. Because of needed too much memory for the analyses, the first 10 second of the ground motions, which is the most effective duration, is taken into account in calculations. The results obtained 3D finite element model are presented. In addition, the displacement and stress results are observed to be allowable level of the concrete material during the earthquakes.

• 한국유체기계학회 논문집
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• 제3권4호
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• pp.52-58
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• 2000

The numerical study on the waterhammer was carried out for the intake pumping station of the metropolitan water supply 6th stage project. Because the waterhammer problems as a result of the pump power failure were the most important, these situations were carefully investigated. The surge tank and the stand pipes effectively protected the tunnels md the downstream region of pipeline from the pressure surge. In case the moment of inertia of the pump and motor was above $5080\;kg{\cdot}m^2$, the column separation did not occur in the pipeline between the pumping station and the inlet of 1st tunnel. As the moment of inertia increased, the pressure surges decreased in the pipeline conveying raw water. The pump control valve was chosen as the main surge suppression device for the intake pumping station. After power failure, the valve disc should be rapidly closed in 2.5 seconds and controlled the final closure to 15 seconds by the oil dashpot. If the slamming happened to the pump control valve, there was some danger of this system damaging. As the reverse flow through the valve increased, the upsurge extremely increased.

• 한국신뢰성학회지:신뢰성응용연구
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• 제9권4호
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• pp.275-290
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• 2009

This paper considers accelerated thermal degradation tests which are performed for rubber seal materials used for undersea tunnels constructed by immersion method. Three types of rubber seals are tested; rubber expansion seal, omega seal, and shock absorber hose. Main ingredient of rubber expansion seal is EPDM(Ethylene Propylene Diene Monomer) and that of both omega seal and shock absorber hose is SBR(Styrene Butadiene Rubber). The accelerated stress is temperature and an Arrhenius model is introduced to describe the relationship between the lifetime and the stress. From the accelerated degradation tests, dominant failure mode of the rubber seals is found to be the loss of elongation. The lifetime distribution and the service life of the rubber seals at use condition are estimated from the test results. The acceleration factor for three types of rubber seals are also investigated.

• Geomechanics and Engineering
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• 제7권1호
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• pp.55-73
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• 2014

The theoretical predictions of ground movements induced by tunnelling are usually based on the assumptions that the subsoil has the same soil densities. The theoretical prediction does not consider the impact of different sand soil types on the surface settlement due to tunnelling. The finite elements analysis (FEA) considers stress and strength parameters of the different sand soil densities. The tunnel construction requires the solution of large soil-structure interaction problem. In the present study, the FEA is used to model soil-tunnel system performance based on a case study to discuss surface displacement due to tunnelling. The Greater Cairo metro tunnel (Line 3) is considered in the present study as case study. The surface displacements obtained by surface displacement equation (SDE) proposed by Peck and Schmidt (1969) are presented and discussed. The main objective of this study is to capture the limitations of the parameters used in the SDE based on the FEA at different sand soil densities. The study focuses on the parameters used in the SDE based on different sand soil densities. The surface displacements obtained by the FEA are compared with those obtained by the SDE. The results discussed in this paper show that the different sand soil densities neglected in the SDE have a significant influence on the surface displacement due to tunnelling.

• Wind and Structures
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• 제24권6호
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• pp.657-677
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• 2017

This paper discusses some features and conditions that characterize the Zonda wind, focusing particularly on the implications for wind engineering applications. This kind of wind, typical of mountainous regions, is far from being adequately characterized for computational simulations and proper modeling in experimental facilities such as boundary layer wind tunnels. The objective of this article is to report the research works that are being developed on this kind of wind, describing the main obtained results, and also to establish some general guidelines for the proper analysis of the Zonda in the wind engineering context. A classification for the Zonda wind is indicated and different cases of structural and environmental effects are described. Available meteorological data is analyzed from the wind engineering point of view to obtain the Zonda wind gust factors, as well as basic wind speeds relevant for structural design. Some considerations and possible directions for the Zonda wind-tunnel and computational modeling are provided. Gust factor values larger than those used for open terrain were obtained, nevertheless, the basic wind speed values obtained are similar to values presented by the Argentinian Wind Code for three-second gust, principally at Mendoza airport.

• 한국터널지하공간학회 논문집
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• 제4권2호
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• pp.167-174
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• 2002

본 연구에서는 시공순서를 고려한 대단면 터널의 안정성 평가를 수치해석에 의해 수행하였다. 일반적으로 터널의 안정성은 최종 굴착 후의 안정성에 의해 판단하는 것이 보통이나, 본 연구에서는 굴착단계별 안정성을 비교·검토하였다. 해석결과를 종합하면, 터널의 안정성에는 별 문제가 없을 것으로 판단되며, 이곳을 시공할 때 계측을 철저히 하는 등의 각별한 주의가 요구된다. 또한, 굴착단계별 안정성을 비교한 결과, 우측 본선터널 상부 반단면 굴착시 (5 단계)의 안정성이 오히려 최종굴착 후의 안정성보다 취약한 것으로 나타났다.