• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.165-172
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• 2001

본 연구에서는 하천인접구간에서와 같이 지하수가 풍부한 지반에서 시공되는 터널의 막장 안정성을 평가하기 위하여 터널 막장에 작용하는 힘의 두 가지 요소를 고려하였다. 하나는 극한해석 중 upper bound solution으로부터 산출된 유효응력이며, 또 하나는 지하수의 정상류 흐름조건을 고려한 수치해석으로부터 산출된 침투력이다. 지하수가 풍부한 토사지반에서의 터널 시공시 터널 막장에 작용하는 힘을 구하기 위하여 침투력을 고려한 극한해석의 해를 구한 결과 터널 막장의 안정성을 유지하기 위한 최소 지보력은 터널 막장에 작용하는 유효응력과 침투력의 합으로 나타낼 수 있었다. 또한 터널 막장에 작용하는 평균침투압은 지하수위에 비례하여 작용하는 것으로 나타났으며, 이를 실내모형 실험 결과를 통하여 검증하였다. 지하수의 정상류 조건 하에서의 토사터널에 대한 실내모형 실험 결과, 터널 막장에 작용하는 침투력은 수치해석 결과 비슷한 양상을 보여주어 제안된 이론의 타당성을 입증하였다.

• Tunnel and Underground Space
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• v.15 no.1 s.54
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• pp.61-70
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• 2005

The objective of this study was to analyze the smoke movement for the case of fire and to determine the interval between emergency exits in long tunnels. Based on Froude modeling, the 1/50 scaled model tunnel (20 m long) was constructed by acrylic tubes and tests were carried out systematically. From the strong relationship between CO propagation time and distance through the tunnel, it was found that the optimal escaping time was 6 minutes in case of 20MW fire. But, regarding passengers' psychological state under fire, another one minute of delay time should be considered. Therefore, the total escaping time should be estimated by 5 minutes. The interval between the emergency exits for vehicle passengers was calculated by 250 m with respect to the 5 minute of escaping time.

• Tunnel and Underground Space
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• v.24 no.4
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• pp.308-315
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• 2014

In this study, reduced scale experiments were carried out to evaluate the effect of external wind in a road tunnel fire. Experiments were conducted in a $1.1m{\times}0.5m{\times}50.4m$ tunnel. 4.5 litter gasoline was used as a fuel. Temperature, oxygen and carbon monoxide concentration were measured. Smoke reaching time to the tunnel exit was affected by the external wind. When a fire was fully developed, wind effect is reduced compared with the early stage of a fire. CO concentration was reached at more than 1,500 ppm.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.227-237
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• 2005

In this study, the behavior of shallow 2-Arch tunnel due to excavation under horizontal discontinuity plane was verified experimentally. The model tests were carried out by varying the overburden height and the location of the discontinuity plane. The model tests followed exactly the real 2-Arch tunnel construction stages. As a result, it is discovered that stress-transfer mechanism and loosening area around the 2-Arch tunnel depends on the overburden heights and the location of the discontinuity plane. And central pillar load is also dependent on overburden height, location of discontinuity plane and construction stages.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.53-61
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• 2006

This study is aimed at to examine the stress redistribution mechanism for tunneling in an unconsolidated ground with inclined layers through model tests. To make the unconsolidated ground, two dimensional model ground is prepared with aluminum rods and blocks, which are frictional resistance free between testing apparatus walls and ground materials, by establishing the ground materials self-supporting. It is carried out to measure the ground deformation and the stress redistribution for model ground with tunneling by measuring apparatus respectively. For the ground deformation, surface settlements are measured to examine the deformation features during tunnel excavation. For the stress redistribution, the earth pressure acting on both the tunneling part and its surrounding parts is measured to examine their mutual relationship. Based on test results, precise examination is conducted on the stress redistribution mechanism in the unconsolidated ground with inclined layers during tunnel construction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.141-149
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• 2004

In this study, smoke movement in tunnel fire with natural and longitudinal ventilation systems has been investigated. Reduced-scale experiments were carried out under the Froude scaling using 14.55kW fire source with a wick and experimental data is obtained with 1/18 model tunnel test. Temperature profiles were measured under the ceiling and vertical direction along the center of the tunnel and poisonous gas was measured at emergency exit point. The results show that refuge time for 225m intervals of emergency exit in case of natural ventilation systems is 256 seconds and critical velocity for sufficient back-layer prevention is 2.8m/s for fire strength of 20MW.

• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.2
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• pp.32-40
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• 2000

This paper presents the results of a parametric study on the behavior of tunnel face reinforced with horizontal pipes. A series of reduced-scale model tests was carried out to in an attempt to verify previously performed three-dimensional numerical modeling and to investigate effects of reinforcement layout on the tunnel face deformation behavior. The results of model tests indicate that the tunnel face deformation can significantly reduced by pre-reinforcing the tunnel face with longitudinal members and thus enhancing the tunnel stability. In addition, the model tests results compare fairly well with those from the previously performed three-dimensional finite element analysis. Therefore, a properly calibrated three dimensional model may effectively be used in the study of tunnel face reinforcing technique.

• Tunnel and Underground Space
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• v.20 no.4
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• pp.260-266
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• 2010

In this study, wish to analyze effect that affect on each tunnel (right and left tunnel) according as proceeding of leading tunnel (right tunnel), following tunnel (left tunnel) and pilot tunnel excavation through behavior of tunnel and surrounding base by model tests. And stress-transfer mechanism that occurs from in-situ loosing area and arching effect by difference of stiffness ratio and overburden heights were verified experimentally. The model tests were carried out by varying the stiffness of reinforced area and overburden height, measured deformation of tunnel and displacement of surrounding base. The model tests followed exactly the real 2-Arch tunnel construction stages.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.99-99
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• 2016

최근 홍수의 특성과 피해 양상은 과거와는 다르게 변화하고 있으며, 급격한 도시화로 인하여 기존 하천유역의 저류 능력이 감소하였는데 이러한 한계를 극복하기 위하여 이미 외국에서는 대심도 터널을 활용한 홍수재해 관리방안이 오래전부터 활용되어 왔다. 본 연구에서는 현재 서울시에 건설중인 '신월 빗물저류배수시설' 연속강우 시 대심도 터널의 수리적 안정성 평가와 운영방안 수립을 위한 수리모형실험을 실시하였다. 모형은 Froude 상사법칙을 사용하여 원형의 1/50크기로 제작하였다. 모형의 전체 저류 가능량은 모형기준 $2.78m^3$ (원형 $347,778m^3$)이며, 터널 내 잔류수는 전체 저류 가능량의 0 ~ 100%까지 10%씩 변화시켜 실험 CASE를 선정하였다. 각 실험CASE별 수직 유입구 안정성 평가를 실시한 결과 터널 내 잔류수가 10%~80%까지 존재 할 때는 저지수직구1에서의 압축공기 폭발현상으로 인한 월류현상이 발생하였으며, 10%~40%까지는 저지수직구2에서 월류현상이 발생하였다. 하지만 고지수직구에서는 모든 CASE에서의 공기폭발 현상 및 월류현상이 발생하지 않아 유입성능 및 공기배출 성능이 충분히 발휘되고 있는 것으로 분석되었다. 또한 저지수직구1에서의 월류현상 발생 시점은 5분55초에서 3분42초까지 빨라졌으며 저지수직구2에서의 월류현상 발생 시점은 5분57초에서 4분57초로 빨라졌다. 이는 터널 내 잔류수량이 증가할수록 터널 내 만관시점이 빨라져 발생하며, 저지수직구1,2에서의 압축공기 폭발현상 및 월류 현상은 터널 내에서 발생한 반사파의 영향으로 판단된다. 차후 터널 내 반사파 발생에 대한 연구가 추가적으로 진행되어야 할 것이다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.609-623
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• 2018

If the ground is excavated in a depth which is deeper than the adjacent existing tunnel, the behavior of the braced wall is known to be greatly affected by the presence of the tunnel. By the way it is expected to be also affected by the structure on the ground surface, There are not many examples of studies which are conducted on this subject. As a result, largel scale model tests and analysis were conducted, to measure the behavior of the tunnel under the building whose location on the ground surface was varied during the adjacent ground excavation. For this purpose, the location of a building load was varied in 0 m, 1D, 2D on ground surface. In this paper, the behaviors of braced wall and adjacent tunnel was studied. Model tests in 1 : 10 scale were performed in real construction sequences. The size of test pit was $2.0m(width){\times}6.0m(height){\times}4.0m(length)$ in dimension. As a result, it was found that the stability of the existing tunnel under the influence of the building load on the ground surface adjacent to the braced wall.