• 건축구조
• /
• v.14 no.4
• /
• pp.79-86
• /
• 2007

Underground space development is more active on the latest date. Currently, we construct an connecting tunnel Euljiro underground shopping-area in seoul. we select DSM, considering geological condition and construction efficiency. The numerical analysis is performed with PENTAGON-3D and MIDAS CIVIL This paper will introduce the Earth Tunnel Method and make an examination possible to apply downtown weak ground.

• Journal of the Korean Geotechnical Society
• /
• v.15 no.6
• /
• pp.251-262
• /
• 1999

The assemblage of the trapezoidal segments, which is being used increasingly to shield tunnelling, with Guide rod and Dowel forms tunnel lining. In this case the larger the taper angle of trapezoidal segment is, the easier the assembly work becomes. The large angle can reduce the water proof material's phenomenon of being pushed back, but decreases the structural safety in connecting section of tunnel lining. In this paper a 3-dimensional numerical analysis was performed to estimate the exact behavior of a model shield tunnel made by connecting 3-dimensionally various accessories with irregular sectioned segments. We obtained the operating force of connecting section according to the change of taper angle of trapezoidal segment and sought for improved scheme for connecting section by comparing and analyzing the test results on the friction resistance force of connecting parts.

• Geomechanics and Engineering
• /
• v.15 no.3
• /
• pp.833-839
• /
• 2018

Dynamic behaviour of a tunnel is one of the most important issues for the safety and it is generally subjected to the seismic response of the surrounding soil. Relative displacement occurred in tunnel lining during earthquake produces severe damage. Generally, it concentrates at the connecting area when two tunnels are connected in the ground. A flexible segment is a useful device for the mitigation of seismic loads on tunnel lining. In this study, 1-g shaking table tests are performed to investigate the acceleration response for the verification of the effect of flexible segment and to determine the optimum location of the flexible segment for connected tunnels. Four different seismic waves are considered; as a result, peak acceleration is reduced to 49% in case that flexible segment is implemented adjacent to connecting area. It also exhibited that the mitigation of acceleration response is verified in all seismic waves. Additionally, 3-dimensional numerical analysis is performed to compare and verify the results. And the numerical results show good agreement to those of the experimental study.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.12 no.1
• /
• pp.43-49
• /
• 2010

The escape connecting gallery in a tunnel on a road is one of emergency equipment to ensure safety for passer in the tunnel against the tunnel fire. Government stipulate over 500m tunnel has the cross passage at intervals of less then 250 m. However, this lump estimated interval is generated the concerns of exaggeration and under construction because peculiarity of the tunnel ex. The velocity of the tunnel airflow, an incline, degree of a fire, and innering area are not considered. The study indicate the way to estimate of the cross passage considered an incline and the velocity of the tunnel airflow for efficient application of cross passage on the tunnel design. As a result, in 0.0 m/s and 1.0 m/s of the velocity of the tunnel airflow case, the movement of smoke is influenced by the incline however, in 20 m/s case, it isn't influenced by incline much. According to the velocity of tunnel airflow and the incline, optimum interval of cross passage is not corresponded. Therefore established lump estimate that has 250 m intervals would be changed to estimate of optimum interval of cross passage that considered about the properties of tunnel, the velocity of the tunnel airflow, incline, degree of a fire and innering area of the tunnel.

• Tunnel and Underground Space
• /
• v.25 no.5
• /
• pp.470-486
• /
• 2015

Two-arch tunnels require minimal spacing between the 2 tunnels and thus occupy small amount of land compared to parallel tunnels. But it is rather expensive. The parallel tunnel is not as expensive, but it requires more land than 2-arch tunnels. This may cause a problem when there is a land shortage. The new design is to connect these two types of tunnels by another pair of parallel tunnels where the separation distance is gradually increasing. The applicability of this new design to the cases where rock condition is not even fair has to be verified since the width of the pillar between the connecting tunnels can be quite narrow. Therefore both two and three dimensional numerical analyses were conducted and pillar stability was examined for rock classes IV and V in two different ways. Results showed that this new design is still effective for poor rock conditions if central pillar is properly reinforced by tension bolts as long as overburden is less than five times of the tunnel diameter.

• Tunnel and Underground Space
• /
• v.24 no.2
• /
• pp.120-130
• /
• 2014

Recently, a few mega projects of subsea tunneling are completed or ongoing or under planning stage all across the world. In Korea, subsea tunnels connecting to Japan and China have been considered in the past decades. At the same time, subsea tunnels connecting to domestic islands were planned with preliminary design concepts. Development and improvement of indigenous techniques regarding subsea tunneling are essential in light of current technical level in Korea and their future impact on tunneling industry. In this paper, distinct features of subsea tunnel and construction trend of subaqueous tunnels are analyzed via case studies. Also, case studies about incidents related to subsea tunneling and required techniques to secure safety are presented.

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

• The Journal of Engineering Geology
• /
• v.7 no.1
• /
• pp.1-10
• /
• 1997

The construction of Kyungbu canal connecting Han and Naktong rivers is needed to facilitate the carriage of goods and enhance the economic growth. The two rivers are liflked by the Choryeong tunnel with 20.5 km length and 125 m altitude. Seven locks involving of 25 m lifting height are planned to reach the tunnel from Shingok dam along the Han river. The tunnel and dams are located favorably by topographic and geologic map analysis. The water needed to fill the chamber of high lock will he supplied by construction of additional dams above Chungju-dam and/or intmduction of water-saving lock system.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.06b
• /
• pp.165-193
• /
• 2003

The Han River tunnel connecting Yoido and Mapo was constructed as a part of the Seoul subway line No.5, which is 52 km long, to improve the traffic conditions of Seoul. It is constructed 15.6∼30m below the river floor. It Is the first under-river tunnel in Korea with the length of 1,288m. Geological conditions of the ground under the Han River were more complex and irregular than expected at the design stage, because there were several faults, fracture zones and slickensided joints coated with graphite. It was thus indispensable to estimate the ground condition of the tunnel face to apply proper excavation and reinforcement methods. Advance borings and face mappings were performed before excavation to improve constructional efficiency and excavation stability.

• Geomechanics and Engineering
• /
• v.35 no.4
• /
• pp.395-409
• /
• 2023

Long-span suspension bridges have tunnel anchor systems to maintain stable cables. More investigations are required to determine how closely tunnel excavation beneath the tunnel anchor impacts the stability of the tunnel anchor. In order to investigate the impact of the adjacent tunnel's excavation on the stability of the tunnel anchor, a large-span suspension bridge tunnel anchor is utilised as an example in a three-dimensional numerical simulation approach. In order to explore the deformation control mechanism, orthogonal tests are employed to pinpoint the major impacting elements. The construction of an advanced pipe shed, strengthening the primary support. Moreover, according to the findings the grouting reinforcement of the surrounding rock, have a significant control effect on the settlement of the tunnel vault and plug body. However, reducing the lag distance of the secondary lining does not have such big influence. The greatest way to control tunnel vault settling is to use the grout reinforcement, which increases the bearing capacity and strength of the surrounding rock. This greatly minimizes the size of the tunnel excavation disturbance area. Advanced pipe shed can not only increase the surrounding rock's bearing capacity at the pipe shed, but can also prevent the tunnel vault from connecting with the disturbance area at the bottom of the anchorage tunnel, reduce the range of shear failure area outside the anchorage tunnel, and have the best impact on the plug body's settlement control.