• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.67-75
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• 2012

Because recently(July 14, 2011) fire occurred in the engine room of a moving taxi under Namsan Tunnel 1, 51 vehicles' driver and more than 250 passengers in the road tunnel were urgently evacuated with abandoned vehicles. Vehicle fires in Namsan Tunnel that day, Sufferers struggled to escape quickly difficult to escape the two-way by abandoned vehicles on the road and to fear many casualties by using vehicle fuel and combustible interior and the driver who is ignorant of vehicle accident continuous entered in the road tunnel had accessibility the site of fire department was more difficult. In this study, It is to investigate structure and basic materials, such as fire extinguish equipment and facilities for damage prevention and to analyze the problems and to plan improvement method of fire extinguish equipment, facilities for damage prevention and transportation facilities(Large traffic signs, Breaker, etc.) on the Namsan Tunnel that in the long-term plan is prepared to strengthen for accessibility of the site of fire department in case of Vehicle's fire.

• Wind and Structures
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• v.12 no.5
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• pp.413-424
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• 2009

A series of wind tunnel free-decay sectional model dynamic tests were conducted to examine the effects of torsional-to-vertical natural frequency ratio of 2DOF bridge dynamic systems on the aerodynamic and dynamic properties of bridge decks. The natural frequency ratios tested were around 2.2:1 and 1.2:1 respectively, with the fundamental vertical natural frequency of the system held constant for all the tests. Three 2.9 m long twin-deck bridge sectional models, with a zero, 16% (intermediate gap) and 35% (large gap) gap-to-width ratio, respectively, were tested to determine whether the effects of frequency ratio are dependent on bridge deck cross-section shapes. The results of wind tunnel tests suggest that for the model with a zero gap-width, a model to approximate a thin flat plate, the flutter derivatives, and consequently the aerodynamic forces, are relatively independent of the torsional-to-vertical frequency ratio for a relatively large range of reduced wind velocities, while for the models with an intermediate gap-width (around 16%) and a large gap-width (around 35%), some of the flutter derivatives, and therefore the aerodynamic forces, are evidently dependent on the frequency ratio for most of the tested reduced velocities. A comparison of the modal damping ratios also suggests that the torsional damping ratio is much more sensitive to the frequency ratio, especially for the two models with nonzero gap (16% and 35% gap-width). The test results clearly show that the effects of the frequency ratio on the flutter derivatives and the aerodynamic forces were dependent on the aerodynamic cross-section shape of the bridge deck.

• Journal of the Korean Professional Engineers Association
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• v.43 no.2
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• pp.34-38
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• 2010

The Busan-Geoje Fixed Link is an 8.2 km long motorway connecting Busan to the island of Geoje where the Korean big two shipbuilding yard locate on. This motorway includes a 3,300m immersed tunnel which is one of the longest immersed tunnel in the world and two cablestayed bridges each of 2km in length. The site locates in a exposed offshore, which is subjected to strong winds, large swell waves and strong tidal currents. These conditions together with the tunnel being at a deepest immersed tunnel ever built and the foundation condition is consisting of a very soft, normally to slightly over consolidated marine clay, makes the project unique and one of the most challenging immersed tunnels ever built.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.15-38
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• 2022

Recently, tunnel technology in Korea has shown various achievements such as long tunnel and large section by tunnel construction using TBM in Korea and abroad. Especially subsea tunnels are frequently designed and constructed. The Ga-deok subsea tunnel was completed in December 2010, and the Incheon North Port Tunnel was opened and operated in 2017, and the Bo-ryeong subsea tunnel between Dae-cheon Port and Won-san Island will be completed in 2021. In foreign countries, many subsea tunnels have been constructed and operated in such as Norway and Japan. The main technical problem in the construction of subsea tunnel is to secure stability due to high water pressure conditions and large-scale seawater inflow in fault zones and weak zones. In this paper, various risk factors and solutions are described in the subsea tunnel planning of national road 77 construction work between Abhae and Hwawon.

• 도로교통
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• s.84
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• pp.23-39
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• 2001

Increasing constructions of tunnels are become larger of the size and longer of the length. Construction of the tunnellinings is in poor working environment, for example, dark and narrow underground. Therefore, it is difficult to constructlining by required quality in these poor working conditions. In case of the designing tunnel in large scale, particularly, there may be several problems as follows; delay of construction due to a long time in constructing lining and difficulty of quality control. It is also indicated that longitudinal cracks of them are main defects in domestic tunnels. Therefore, in this study, the precast lining method is introduced for solving problems, which are delay of the tunnel construction a d deterioration of tunnel lining. Precast linings have mainly been constructed in Norway and North Europe. A new construction method of tunnel lining, suitable in domestic situation, is introduced by detailed case study. Also, useful materials for design and construction of Precast lining are presented.

• Wind and Structures
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• v.23 no.6
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• pp.595-613
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• 2016

Large amplitude oscillation of steepled main cables usually presents during construction of a long-span bridge. To study this phenomenon, six typical main cables with different cross sections during construction are investigated. Two main foci have been conducted. Firstly, aerodynamic coefficients of a main cable are obtained and compared through simulation and wind tunnel test: (1) to ensure the simulation accuracy, influences of the numerical model's grid size, and the jaggy edges of main cable's cross section on main cable's aerodynamic coefficients are investigated; (2) aerodynamic coefficients of main cables at different wind attack angles are obtained based on the wind tunnel test in which the experimental model is made by rigid plastic using the 3D Printing Technology; (3) then numerical results are compared with wind tunnel test results, and they are in good agreement. Secondly, aerodynamic coefficients of the six main cables at different wind attack angles are obtained through numerical simulation. Then Den Hartog criterion is used to analyze the transverse galloping of main cables during construction. Results show all the six main cables may undergo galloping, which may be an important reason for the large amplitude oscillation of steepled main cables during construction. The flow structures around the main cables indicate that the characteristic of the airflow trajectory over a steepled main cable may play an important role in the galloping generation. Engineers should take some effective measures to control this harmful phenomenon due to the big possibility of the onset of galloping during the construction period.

• Structural Engineering and Mechanics
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• v.84 no.5
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• pp.699-706
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• 2022

Settlement control techniques are critical for the safety of shield tunnel constructions, especially for facing complex situations. In this study, the shield tunnel structure from Huaita east road station to Heping Road station in Xuzhou metro No.3 line (China) is taken as engineering background, which has various complex problems of the upper-soft and lower-hard composite stratum conditions, twin curve shield tunnels, and underpass the foundation of the piled raft. The deformation characteristics of shield tunnelling passing through buildings are explored. Subsequently, comprehensive research methods of numerical simulation and field measurement are adopted to analyzing the effectiveness of settlement control by using the top grouting technique. The results show that the settlement of the buildings has obvious spatial characteristics, and the hysteresis effect can be obviously observed in soil deformation caused by shield construction. Meanwhile, the two shield constructions can cause repeated disturbances, reducing the soil deformation's hysteresis effect. Moreover, the shield tunnel's differential settlement is too large when a single line passes through, and the shield construction of the outer curve can cause more significant disturbance in the tunnel than the inside curve. Notably, the proposed process control parameters and secondary topgrouting method can effectively control the deformation of the shield tunnel, especially for the long-term deformation.

• Tunnel and Underground Space
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• v.15 no.6 s.59
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• pp.432-440
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• 2005

Baehuryeong tunnel connects Chuncheon with Hwacheon in Kangwon, Korea, This tunnel is a single tunnel with 5,057 m long and two bidirectional lanes which will be extended into low lanes in the future. The estimated construction period of Baehuryeong tunnel is approximately 55 months. This tunnel will become the longest bidirectional roadway tunnel in Korea. Compared to a twin tunnel, a bidirectional single tunnel has two major disadvantages with regard to the ventilation system and ease of escape during fire. For these reasons, a service tunnel and the transverse ventilation system are planned first time in Korea. In case of fire, the tunnel ventilation design aims to maintain a smoke free layer for passenger evacuation. The geology of Baehuryeong tunnel site is mainly composed of gneiss and granite. Baehuryeong fault is a mainly large scale fault which stands vertical and parallels with tunnel direction. The influenced zone of this fault is within 70 m. Baehuryeong tunnel was designed that it was separated with the distance of more than 100 m from Baehuryeong fault for its safety.

• Journal of the Korean GEO-environmental Society
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• v.24 no.12
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• pp.53-60
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• 2023

Recently, along with the improvement of high-speed rail and road design speed, the proportion of tunnel construction work is increasing proportionally. In particular, the construction of long tunnels is rapidly increasing due to the mountainous terrain of our country. In this way, due to the trend of tunnels becoming longer, it is difficult to design and construct tunnels by avoiding fault zones. In the case of tunnel construction in mountainous areas, ground investigation is often difficult even during design due to the topographical conditions, making precise ground investigation difficult, and as a result, the upper part of the tunnel is damaged during tunnel construction. When fault zones, which are vulnerable to weathering, exist, the stability of the tunnel during excavation is directly affected by the fault zone distribution, strength characteristics, and groundwater distribution range. In particular, when a fault zone is distributed in the upper part of a tunnel, damage such as tunnel collapse and excessive displacement may occur, and in order to prevent this in advance, countermeasures must be established through analysis of similar cases. Therefore, in this study, when a large-scale fault zone exists in the upper part of a tunnel, the relationship and characteristics of damage to the tunnel structure were analyzed.

• Journal of the Korea Institute of Building Construction
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• v.4 no.1
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• pp.97-103
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• 2004

In case of a fire in road or railway tunnel it is always necessary to keep the escape condition as good as possible. Most of the victims of major fires in tunnels are because they couldn't leave the tunnel in time and were trapped by smoke, or rescue teams couldn't reach the place of the accident due to low visibility and high temperature. In spring 2003 a comprehensive field experiment was undertaken in a large scaled tunnel in Youngin City to test the effectiveness of a new water spray curtain system, designed to the air qualify inside of a tunnel in case of fire during passenger's escape to safe routes, In order to control the smoke propagation, fixed water sprayed nozzles were used to make water curtain system, which can be installed or hanging water piping line below ceiling. The experiment was accompanied by an extensive measurement campaign in order to measure temperature dropping effect and flow conditions as well as CO concentration for various water sprayed curtains produced by sprinkler heads or water spray nozzle. Eventually comparison analysis were undertaken to investigate the performance of water curtains under fixed water pressure. Therefore most effective water curtain system was presented on the basis of water droplet size in long tunnel.