• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집B
• /
• pp.619-624
• /
• 2000

The purpose of present study is to investigate for reducing micro pressure waves generated according to train speeds $(240km/h{\sim}380km/h)$ through tunnels with countermeasures as followings; the hood configuration in tunnel entrance. We developed hoods for tunnel of 0.5 km length in the condition of tunnel cross-section area of $107m^2$ on the slab track. According to the results the maximum micro-pressure wave is reduced by 41.2% for the slit hood installed at the entrance of the tunnel and reduced by 47.7% for the slit hood installed at the entrance of the tunnel and the $45^{\circ}$ slanted portal at the exit of the tunnel

• 전기학회논문지
• /
• 제65권8호
• /
• pp.1392-1399
• /
• 2016

Blackout effect occurs when a driver misadapts to the changed lighting conditions upon entering a tunnel. This could lead to a decrease in visibility especially in the daylight, depending on the difference in the degree of brightness between inside and outside the tunnel. To alleviate such a problem, we decrease windshield transparency before the driver arrives at the tunnel entrance. Controlled amount of light inside the car can allow the drivers to adjust to the dark prior to entering. The windshield transparency coefficient is to be determined by the arrival time at the tunnel and difference in the level of brightness between inside and outside the tunnel. Navigation, road sign detection, and tunnel entrance detection provide the arrival time. We also designed an opto-electronic conversion function to estimate the level of brightness. The black-hole phenomenon alleviation method is verified by field experiments using an automobile camera and a navigation. The result shows that the adjusted windshield transparency is able to provide an environment with a comfortable level of brightness with which the drivers can enter tunnels without the visibility problem.

• 한국터널지하공간학회 논문집
• /
• 제7권3호
• /
• pp.259-267
• /
• 2005

본 논문에서는 터널별로 매설된 온도계의 연중계측을 통하여 년 중 온도변화특성과 갱구부로부터의 길이별 온도변화특성, 터널연장별 대기 온도변화특성, 지표부 온도 변화특성을 분석하였다. 터널의 연장별 터널내 바닥부 온도 분포에 대한 분석 결과 입구부와 출구부가 다른 온도분포를 보임을 알 수 있었다. 출구부에서의 터널내 바닥부 표면온도 분포는 출구부에서 50m 지점까지는 온도가 변하다가 50m 이후 깊이에서는 터널연장에 상관없이 거의 일정한 온도분포를 보임을 알 수 있었다. 그러나 입구부에서의 터널내 바닥부 표면온도 분포는 출구부와 달리 터널내 길이 약 125~150m 지점에서 본도분포가 변하고 있음을 알 수 있었다. 이는 입구부로 유입되는 찬공기가 풍향 및 풍속의 영향을 받아 터널깊이 약 125~150m 지점까지 영형을 끼치는 것으로 보인다.

• 대한기계학회논문집B
• /
• 제25권6호
• /
• pp.758-765
• /
• 2001

Purpose of the present is to investigate the food configuration at a tunnel entrance for reducing the micro pressure wave that is generated according to train speed. Two configurations were examined for tunnel of 0.5 km length. The experimental results show that a slit cover hood installed at the entrance of the tunnel reduces the maximum micro pressure wave by 41.2%, and a configuration with a slit cover hood installed at the entrance and a 45$^{\circ}$slanted portal at the exit of the tunnel suppresses it by 47.7%.

• 한국지열·수열에너지학회논문집
• /
• 제14권3호
• /
• pp.21-28
• /
• 2018

This paper presents two-step simulations to calculate the influence of blast-induced pressures on explosion-protection valves installed at the boundary between a protection facility and a tunnel entering the facility. The first step is to calculate the respective overpressure on the entrance and exit of the tunnel when an explosion occurs near the tunnel entrance and exit to approach the protection facility. Secondly, the blast pressures on the explosion-protection valves mounted to walls located near the tunnel inside approaching the protection facility are analyzed with a 0.1 ms time variation using the results obtained from the first-step calculations. The following conclusions could be derived as a results: (1) The analysis of the entrance tunnel scenario, P1, leads to the maximum overpressure of 47 kPa, approximately a half of the ambient pressure, at the inner entrance due to the effect of blast barrier. For the scenario, P2, the case not blocked by the barrier, the maximum overpressure is 628 kPa, which is relatively high, namely, 5.2 times the ambient pressure. (2) It is observed that the pressure for the entrance tunnel is effectively mitigated because the initial blast pressures are partially offset from each other according to the geometry of the entrance and a portion of the pressures is discharged to the outside.

• 한국지열·수열에너지학회논문집
• /
• 제17권4호
• /
• pp.79-90
• /
• 2021

This paper presents a study to reduce the effect of blast pressure on the blast valves installed in protection tunnels, where the shape of the tunnel entrance and the blast pocket is optimized based on the predetermined basic shape of the protective tunnels. The reliability of the numerical tunnel models was examined by performing analyses of mesh convergence and overpressure stability and with comparison to the data in blast-load design charts in UFC 3-340-02 (DoD, 2008). An optimal mesh size and a stabilized distance of overpressure were proposed, and the numerical results were validated based on the UFC data. A parametric study to reduce the blast overpressures in tunnel was conducted using the validated numerical model. Analysis was performed applying 1) the entrance slope of 90, 75, 60, and 45 degrees, 2) two blast pockets with the depth 0.5, 1.0, and 1.5 times the tunnel width, 3) the three types of curved back walls of the blast pockets, and 4) two types of the upper and lower surfaces of the blast pockets to the reference tunnel model. An optimal solution by combining the analysis results of the tunnel entrance shape, the depth of the blast pockets, and the upper and lower parts of the blast pockets was provided in comparison to the reference tunnel model. The blast overpressures using the proposed tunnel shape have been reduced effectively.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집B
• /
• pp.841-846
• /
• 2000

The compression wave produced when a high-speed train enters a tunnel propagates along the tunnel ahead of the train. The micro pressure wave related to He compression wave is a special physics Phenomena created by high-speed train-tunnel interfaces. On this work, the method for reducing the micro pressure wave is to delay the gradient of the compression wave by using aerodynamic structures. The objective of this paper is to determine the optimum angle of the slanted portal using the moving model rig. According to the results of the present study, the maximum value of micro pressure wave is reduced by 19.2% fer the $45^{\circ}$ slanted portal installed at the entrance of the tunnel and reduced by 41.9% far the $45^{\circ}$ slanted portals at the entrance and exit of the tunnel. Also it is reduced by 34.6% for the $30^{\circ}$ slanted portals installed at the entrance and exit of the tunnel.

• 지질공학
• /
• 제23권3호
• /
• pp.283-292
• /
• 2013

석회암 사면에서 터널 출입구를 시공하기 위하여 진입로를 개설하던 중 사면붕괴가 발생되었다. 사면의 붕괴원인을 조사하기 위하여 현장조사, 실내시험 및 수치해석을 수행하였다. 수치해석결과에 따르면 터널 출입구 진입로 개설이전 사면안전율은 1.0이하이며, 진입로 개설이후 사면안전율은 더 저하되는 것으로 나타났다. 그리고 진입로 개설이후 전단변형률 및 소성영역은 사면상부에서 하부로 전이되므로 사면활동영역이 증가되어 사면안정성을 저하시키는 것으로 해석되었다. 터널 출입구 시공을 위해서는 해당사면에 대한 안정성을 확보하여야 하므로, 대상현장의 조건을 고려하여 록볼트, 록앵커 및 FRP 그라우팅을 사면에 보강하는 것으로 결정하였다. 적용된 사면보강공법의 효과를 확인하기 위하여 현장계측을 수행하였다. 현장계측결과 사면지반의 수평변위는 매우 미소하며, 대부분 발생된 이후 다시 회복되는 탄성거동을 보였다. 그리고 록볼트 및 앵커축력은 터널굴착작업 및 장마기간에 의한 영향보다는 사면굴착작업시 영향을 가장 크게 받으며, 터널굴착작업이후 수렴하는 경향을 보이므로 대상사면은 안정한 상태임을 확인할 수 있다.

• 한국터널지하공간학회 논문집
• /
• 제2권3호
• /
• pp.3-11
• /
• 2000

본 연구의 목적은 고속철도 터널 입구에 슬릿 커버 후드를 적용하여, 고속열차 터널 진입시 터널 출구 쪽에서 방사되는 미기압파를 저감시키는데 있다. 경부고속철도 $107m^2$의 단면적을 갖는 슬라브 궤도 0.5 km 터널에 대하여 슬릿 커버 후드라는 구조물 대책을 마련하였다. 개발시험 결과는 터널 입구에만 후드를 설치했을 경우 미기압파가 최대 41.2 %가 저감되었으며, 터널 입구에 후드를 설치하고 출구에 $45^{\circ}$ 경사갱구를 설치했을 경우는 47.7 %가 저감되었다.

• 한국도시철도학회논문집
• /
• 제6권4호
• /
• pp.309-317
• /
• 2018

Sudden pressure changes caused by the high-speed train entering the entrance of the tunnel are propagated into the tunnel and spread out around the tunnel in the form of a micro pressure wave at the exit of the tunnel. This phenomenon can cause noise and vibration around the tunnel, causing damage to the surroundings. Analysis of this phenomenon is very difficult, but the development of analytical technology has revealed more phenomena than in the past. In this study, we propose this method of analysis and compare it with the experimental data to show the data with higher reliability.