• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.4
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• pp.285-303
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• 2023

Interest in building underground spaces is increasing for the creation of downtown infrastructure and efficient space utilization. A representative method of utilizing underground space is a tunnel, and in addition to road tunnels, the construction of utility tunnels such as power conduits and utility conduits is gradually increasing. The current basic tunnel construction method can be divided into NATM (New Austrian Tunnelling Method) and TBM (Tunnel Boring Machine). The NATM is a reliable method, but it is accompanied by vibration and noise due to blasting. In the case of the TBM excavation method, there are disadvantages in terms of construction period and construction cost, but it is possible to improve economic feasibility by introducing appropriate complementary methods. In this study, a blasting method was develop using the NATM after TBM pre-excavation using the protective shield method. This is a method that compensates for the disadvantages of each tunnel construction method, and is expected to reduce construction costs, blasting vibration, and noise. In order to review the performance of the developed method, an experiment was conducted to evaluate the performance of explosion-proof tube to which a protective shield scale model was applied, and the impact of blasting vibration of the protective shield method was analyzed.

• 방재와보험
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• s.111
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• pp.12-18
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• 2006

일반적으로 긴 일방향성의 형상을 가진 터널의 구조는 화재 및 각종 사고 발생시 정보나 피난동선의 확보가 제한되어 인명피해 우려가 높은 특수한 방호공간이다. 따라서 터널의 화재 위험 및 관리실태를 점검하여 과학적이고 체계적인 종합 안전 대책을 수립하여야 한다.

• Magazine of korean Tunnelling and Underground Space Association
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• v.20 no.4
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• pp.25-31
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• 2018

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.377-396
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• 2019

Explosion after penetration of a warhead in an underground structure generally causes considerable displacement, breakage and extensive damage to the target. Therefore, in order to reduce the damage effect, it is required to design an underground structure protection against penetration. In this study, major factors for improvement of penetration protection performance of reinforced concrete underground structures using applied element method are divided into strength (concrete UCS) and density (concrete thickness, reinforcement layers, reinforcement diameters, reinforcement spacings). Based on these major factors, this study performed numerical analysis of simulation of dynamic response by penetrators under various conditions and analyzed the results. The results of this study are expected to be used as basis materials to improve penetration protection performance of reinforced concrete underground structures.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.235-245
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• 2008

Since rapidly increase of tunnel with increasing of expressway, the study on safety improvement of safety device at entrance of expressway tunnels is necessary. The existence of tunnel occurs more speed reduction than an upward slope by itself, the collision accident of tunnel entrance causes heavier damage than that of general accident on the road. So, many kinds of safety devices such as poly-ethylene barrier, guard-rail are placed on the road side. But these devices affect the drivers as an obstacle. Although there are various safety devices that are placed at tunnel entrance, this study is related to following 2-cases. One is that the poly-ethylene barrier is placed and the other is that a safety devices is not placed. The reason that these two cases are selected, is that poly-ethylene barrier is usually placed at many tunnel entrances and safety devices can affect the drivers as an obstacle. This study is related to the difference of right-hand side clearance between inside tunnel and outside tunnel, too. The average difference observed car speed and VDS(vehicle detect system) speed nearby the tunnel is analysed. Through the statistical analysis of the average difference, this study suggests an alternatives on safety improvement of safety devices at entrance of expressway tunnels. It is concluded that the small difference of right-hand side clearance is desirable to drivers when a poly-ethylene barrier is placed. And when the difference of right-hand side clearance is large, no safety devices is desirable, and when the difference of right-hand side clearance is small, poly-ethylene barrier should be placed to improve safety.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.4
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• pp.79-90
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• 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.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.04a
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• pp.135-143
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• 2003

• Journal of Korean Association for Spatial Structures
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• v.23 no.1
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• pp.25-34
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• 2023

This paper presents a computational fluid dynamics (CFD) analysis to investiagate the effect of expansion chamber on overpressure reduction in protective tunnels subjected to detonation of high explosives. A commercial CFD code, Viper::Blast, was used to model the blast waves in a protective tunnel with a length of 160 m, width of 8.9 m and height of 7.2 m. Blast scenarios and simulation matrix were establihsed in consideration of the design parameters of expansion chamber, including the chamber lengths of 6.1 m to 12.1 m, widths of 10.7 m to 97 m, length to width ratios of 0.0 to 5.0, heights of 8.0 m and 14.9 m, and ratios of chamber to tunnel width of 1.2 to 10.9 m. A charge weight of TNT of 1000 kg was used. The mesh sizes of the numerical model of the protective tunnel were determined based on a mesh convergence study. A parametric study based on the simulation matrix was performed using the proposed CFD tunnel model and the optimized shape of expansion chamber of the considered tunnel was then proposed based on the numerical results. Design recommendations for the use of expansion chamber in protective tunnel under blast loads to reduce the internal overpressures were finally provided.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.295-303
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• 2015

This paper presents the study of leakage effect due to multi-cell inflater of rapid protection system to protect the possibilities of tunnel damages by flooding threats and unusual leakage to be occurred during and after subsea tunnel construction. Particularly, this protect system should be necessary in subsea tunnel. This research concentrates the physical model tests due to several multi-cell inflater to study protection capacity of leakage between the inflater and tunnel liner. A 27:1 small scale model are used in the model tests. The leakage rate, water pressure and axial displacement of inflater are measured during the model tests. According to the results, the minium leakage rate clearly shows in the case of two-cell inflater compared with in other cases. It is concluded that the results of this research will be very useful to understand the fundamental information of inflater structure design and development the technology of tunnel protection structures in the future.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.31-31
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• 2011

1990년 이후 공산체계인 구소련과 동구권이 몰락하고 세계적으로 탈냉전의 변화와 우리의 민주정부 수립 후 햇빛정책 등에도 불구하고 북한은 적화통일을 포기하지 않고 작년 11월에 연평도에 포격을 가하여 민간인과, 군이 2명이 사망하는 사건이 발생 하였다. 또한 북한의 공격은 과거의 포탄공격뿐만 아니라 미사일이나 화생방과 같은 생화학물질 탑재 가능한 공격이 예상된다. 이에 대비 정부에서는 고정시설의 화생방 방호는 일단유사시에 국민의 생명과 재산을 보호하는데 필수요소로서 집단보호개념에 도입하고 있으며, 현재 각 중요 대피시설 및 지자체의 기존 대피시설을 개인방호, 탐지, 제독, 운용절차를 포함한 실태파악 및 재래식 탄을 포함한 통합적인 조치를 마련하고 있다. 작년 2010년 11월 연평도에서의 북한 포격이후 우리는 서해5도나 접경지역 주민과 그리고 근접거리의 서울시민들이 안전하게 포격으로부터 피난 할 수 있는 민방위대피소에 대한 문제점이 대두되고 대책방안을 요구하고 있다. 소방방재청 기준에 따르면 직격(直擊) 핵폭탄을 제외한 화생방, 재래식 무기 공격에 견딜 수 있는 시설은 '1등급 대피시설'인데 서울에는 한 곳도 없다. 고층건물의 지하 2층 이하나 지하철, 터널 같은 2등급 대피시설도 폭격은 견딜 수 있지만 화생방 공격에는 취약하다. 지하상가 등 건축물의 지하층, 지하차도나 보도는 그보다 더 취약한 3등급이며 단독 주택의 지하층처럼 방호 효과가 떨어지는 곳이 4등급이다. 2등급으로 분류된 대피소의 경우 분류만 되어 있을 뿐 장기간 대피시 시민들이 사용 할 수 있는 거주공간이 아닌 임시 대피로서의 역할만 하고 있다. 본 연구에서는 민방위 기본법에 따라 지하에 $3.3m^2$ 당 4명 이상이 대피할 수 있는 규모의 공간을 갖추기만 하면 대피시설로 볼 수 있는 현 문제점과 1등급에서 4등급으로 나뉘어져있는 민방위 대피소와 대피소가 있지만 피난공간으로서의 역할과 구조적으로 안전한가에 대한 국내외 실태 분석을 통하여 분석한 결과 우리는 서해5도 대피시설의 반 이상이 무용지물이고 접경지 또한 피난시에 피난장으로서의 대피소가 난방이나, 구급품과 식구 시설 등이 구비가 되어 있지 않고 대피시설로 지정한곳이 간판이나 안내시설이 없다. 외국의 경우 스위스는 연방정부의 관리책임으로 전쟁이나 핵 확산에 따른 화생방 업무 전담팀을 두고 있으며, 방독면은 개인 방호물자로서 전국민 100% 보유하고, 각가정이나 건축, 시설물의 경우 화생방 표준 대피시설 설치관련 규정 마련 시행하고 있다. 대피시설은 화생방 방호가 가능한 지휘부용 대피시설과 일반 주민대피용 시설을 구분하여 설치운영하고 있으며, 전국에 650만개를 설치하고 있다. 결론은 대피시설이 북한 공경시 피난시설로의 활용방안을 모색 등급구분에 따른 현실적용 수정과 기존 대피소 보강과 재선별이 필요하고, 신축시 설계 표준설계안 그리고 기존의 대피소에 대한 보수, 보강방법 가이드라인과 장기간 거주에 대한 설비구축 등과 국민 대홍보등을 제안하였다.