• 한국전산유체공학회지
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• 제10권2호
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• pp.60-68
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• 2005

For study on the unsteady wall interference effect, flows around a forced oscillating airfoil in closed test-section wind tunnels have been numerically investigated by solving compressible Navier-Stokes equations. The numerical scheme is based on a node-based finite-volume method with the Roe's flux-difference splitting and an implicit time-integration method coupled with dual time-step sub-iteration. The Spalart-Allmaras one-equation model is employed for the turbulence effect. The computed results of the oscillating airfoil having a thin wake showed that the lift curve slope is increased and the magnitude of hysteresis loop is reduced by the interference effects. Since the vortex around the airfoil is generated and convected downstream faster than the free-air condition, the phase of lift, drag and pitching moment coefficients was shifted. The pressure on the test section wall shows harmonic terms having the oscillating frequency contained in the wail effect.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1328-1332
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• 2010

The enlargement of existing tunnels is required to cope with problems related to traffic congestion. Sometimes, the tunnel traffic must be maintained through existing tunnels during their reconstruction due to non-availability of detours. And excavation by drill and blasting is desired for widening a hard rock tunnel. In this case, the road must be closed for some period for blasting through analyzing of traffic volume. In this paper, a case study on some traffic countermeasures for tunnel enlargement by blasting was performed. And the traffic flow characteristics of some tunnels in domestic main city were analyzed.

• 자동차안전학회지
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• 제13권4호
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• pp.73-80
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• 2021

Recently, Korea has established a plan for the supply of hydrogen vehicles and is promoting the expansion of the supply. Risk factors for hydrogen vehicles are hydrogen leakage, jet fire, and explosion. Therefore Safety measures are necessary for this hazard. In addition, risks in semi-closed spaces such as tunnels, underground roads, and underground parking lots should be analyzed. In this study, an explosion experiment was conducted on a hydrogen tank used in a hydrogen vehicle to analyze the risk of a hydrogen vehicle explosion accident that may occur in a semi-closed space. As results, the effect on the structure and the human body was analyzed using the overpressure and impulse values for each distance generated during the explosion.

• 한국터널지하공간학회 논문집
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• 제5권4호
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• pp.371-388
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• 2003

최근 시공되고 있는 터널은 2Km 이상의 장대 터널로서 자동차 바퀴와 포장면의 마찰로 인한 주행 소음이 매우 심각한 실정이다. 특히, 터널 내부의 콘크리트 포장은 터널의 폐쇄적인 특성으로 주행 소음의 불쾌감이 가중되고 포장에서 발생하는 분진은 티널 내 환경을 오염시키는 요인이 되고 있어 이에 대한 대책이 시급하다. 본 연구는 터널 내부에서 발생하는 주행 소음을 줄이기 위한 방안으로 선진 외국에서 채택하고 있는 각종 포장표면처리공법을 조사하여 각 공법에 대한 소음 저감 효과와 시공 방법 및 사례를 조사 분석하였다. 터널 내 각종 표면처리공법을 콘크리트포장에 이용할 경우 5dB~10dB까지 소음을 감소시킬 수 있다. 골재노출표면공법은 소음저감 및 미끄럼 저항성 향상 측면에서 기타 다른 포장표면처리공법에 비해 가강 적절한 공법으로 평가되었다. 그러나 국내 실정에 적합한 저소음 포장공법의 개발을 위해서는 장비의 도입, 설계, 시방규정의 재정립이 필요한 것으로 분석되었다.

• Smart Structures and Systems
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• 제24권5호
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• pp.587-595
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• 2019

Deformation measurement of large scale structures, such as the ground beds of high-rise buildings, tunnels, bridge, and railways, are important for insuring service quality and safety. The pose-relay videometrics method and displacement-relay videometrics method have already presented to measure the pose of non-intervisible objects and vertical subsidence of unstable areas, respectively. Both methods combine the cameras and cooperative markers to form the camera series networks. Based on these two networks, we propose two novel videometrics methods with closed-loop camera series network for deformation measurement of large scale structures. The closed-loop camera series network offers "closed-loop constraints" for the camera series network: the deformation of the reference points observed by different measurement stations is identical. The closed-loop constraints improve the measurement accuracy using camera series network. Furthermore, multiple closed-loops and the flexible combination of camera series network are introduced to facilitate more complex deformation measurement tasks. Simulated results show that the closed-loop constraints can enhance the measurement accuracy of camera series network effectively.

• 터널과지하공간
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• 제13권4호
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• pp.245-259
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• 2003

Refering to the articles "Squeezing rocks in tunnels(Barla, 1995)" and "Tunnelling under squeezing rock conditions(Barla 2002)" this article deals with technologies for design, stability analysis and construction of the tunnel being driven in the squeezing rock mass. The definition of this type of behavior was proposed by ISRM(1994). The identification and quantification of squeezing is given according to both the empirical and semi-empirical methods available to anticipate the potential of squeezing problems in tunnelling. Based on the experiences and lessons learned in recent years, the state of the art in modem construction methods was reported, when dealing with squeezing rock masses by either conventional or mechanical excavation methods. The closed-form solutions available for the analysis of the rock mass response during tunnel excavation are described in terms of the ground characteristic line and with reference to some elasto-plastic models for the given rock mass. Finally numerical methods were used for the simulation of different models and for design analysis of complex excavation and support systems, including three-dimensional conditions in order to quantify the influence of the advancing tunnel face to the deformation behavior of the tunnel.

• 한국구조물진단유지관리공학회 논문집
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• 제22권4호
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• pp.27-36
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• 2018

현재 적용되고 있는 평가체계는 1996년 개정되어 이후 4차례 개정을 실시하였으나, 구조적 안전성의 확보 목표에 국한된 평가체계로 인해 장기적 관점의 성능저하 예측 및 예산투입을 위한 우선순위 의사결정의 근거로 활용하기에는 부족하다. 따라서, 본 연구에서는 델파이 기법과 AHP기법을 활용하여 기존 도로터널의 여러 구조형식 중 재래식(ASSM) 터널의 성능평가에 적합한 평가체계를 새롭게 제시하고자 한다. 국 내외의 기존 평가체계 및 평가항목을 검토한 결과, 도출가능한 평가항목이 한정적인 것으로 판단되어 기존에 적용되고 있는 항목에 대한 폐쇄적인 설문과 새로운 항목 도출을 위한 개방형 설문을 병행하여 설문조사를 실시하였다. 조사한 설문결과를 내용타당도 검증을 거쳐 재래식(ASSM)터널에 적합한 성능평가인자를 도출하였으며, AHP기법을 활용하여 도출된 평가항목에 대한 가중치를 산정한 후 구조물의 특성에 맞는 성능평가 체계를 새롭게 제시하여, 향후 성능평가 세부지침 수정 및 보완 시 참고자료로 활용될 수 있도록 하고자 한다.

• 한국지반공학회논문집
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• 제23권4호
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• pp.185-197
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• 2007

한계해석법인 상 하계법은 점착성, 점착성-마찰성, 마찰성분만 가지는 지반에서의 주로 얕은 터널에 대한 안정수를 구하기 위해 발전되어 왔다. 그러나 점성이 없고 마찰성분만 존재하는 지반에서의 비교적 깊은 터널에 대한 이러한 해석법의 연장은 현재까지 그 연구가 드물게 진행되어왔다. 따라서 본 연구는 이러한 상황에서의 터널붕괴하중을 구하기 위한 근사적인 해석법으로 응력불연속장에 근거하는 하계법과 동적 파괴메카니즘에 근거하는 상계법을 각각 제안하였다. 이러한 해석법에 의한 터널붕괴하중은 수치해석과 기존의 경계해석법과 비교되었으며 특히, 터널 수평축 상에 위치하는 유한지반요소들에 대한 유한요소해석 결과와 잘 일치됨을 보여 주었다.

• 대한안전경영과학회지
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• 제24권4호
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• pp.143-148
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• 2022

This paper attempted to analyze the correlation between the risk image of the evacuees in the tunnel and the variables that affect the evacuation behavior due to the closed feeling. As to whether there is a difference in the level of recognizing the tunnel risk image according to the distribution of jobs, the null hypothesis was rejected at the significance probability of 0.002, so it can be said that the level of recognition of the tunnel risk image varies depending on the job group. In the distribution difference between gender and tunnel risk image recognition level, the significance probability was 0.012, indicating that the null hypothesis was rejected, indicating that the tunnel risk recognition distribution according to gender was different. As a result of analyzing the distribution difference between the tunnel's closed feeling and the tunnel risk perception level, the significance probability was 0.001, and the null hypothesis was rejected, indicating that there was a difference in the tunnel risk image level.

• 지질공학
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• 제32권1호
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• pp.1-12
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• 2022

Based on the extended spatial mobilization plane (SMP) criterion, we present an elastic-brittle-plastic solution for an axisymmetric cylindrical tunnel. The influences of the intermediate principal compressive stress and material strain-softening behavior are considered. Closed-form formulas for the critical support force, radius of plastic zone, and distributions of stress and displacement in surrounding rock are proposed. The elastic-plastic solution based on SMP is compared with the Kastner solution to verify the credibility of the obtained elastic-plastic solution. The elastic-brittle-plastic solution following the SMP criterion and the current solution based on the Mohr-Coulomb criterion are also compared. The rock strain-softening rate and the intermediate principal stress affect the stability of the surrounding rock. The results provide guidance for optimizing the design of support systems for tunnels.