• Tunnel and Underground Space
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• v.33 no.4
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• pp.209-227
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• 2023

The government continues to announce measures to revitalize smart construction technology based on BIM for productivity innovation in the construction industry. In the design phase, the goal is design automation and optimization by converging BIM Data and other advanced technologies. Accordingly, in the basic design of the Namhae Seomyeon-Yeosu Sindeok National Road Construction Project, a domestic undersea tunnel project, BIM-based design was carried out by developing tunnel design automation technology using 3D spatial information according to the tunnel design process. In order to derive the optimal alignment, more than 10,000 alignment cases were generated in 36hr using the generative design technique and a quantitative evaluation of the objective functions defined by the designer was performed. AI-based ground classification and 3D Geo Model were established to evaluate the economic feasibility and stability of the optimal alignment. AI-based ground classification has improved its precision by performing about 30 types of ground classification per borehole, and in the case of the 3D Geo Model, its utilization can be expected in that it can accumulate ground data added during construction. In the case of 3D blasting design, the optimal charge weight was derived in 5 minutes by reviewing all security objects on the project range on Dynamo, and the design result was visualized in 3D space for intuitive and convenient construction management so that it could be used directly during construction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.198-200
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• 2014

부산 강서구 천성동에 소재한 중죽도는 해양문화공간으로 조성할 수 있는 다양한 잠재력과 가능성을 가지고 있다. 거가대교의 지상부분으로 연결되는 장소에 있는 중죽도와 대죽도는 거가대교를 건설하면서 육지와 침매 해저터널로 연결된 무인도이다. 이러한 시설을 조성하면서 자연스럽게 형성된 방파제와 매립지는 중죽도와 인접한 까닭에 육지에서 자동차로 접근이 가능한 공간이다. 때문에 무인도라는 섬을 자동차로 갈 수 있다는 장점뿐 아니라 육지의 전기가 공급된다는 장점도 있다. 특히 대형차량을 위한 주차시설과 거가대교 홍보관이 있는 가덕해양파크 휴게소에서 차량을 이용하여 접근이 가능하므로 이 시설과 연계한 관광상품도 개발이 가능한 현실이다. 국내 유일의 이러한 환경을 활용하여 친환경적인 개념을 도입하여 각종 시설을 계획한다면 매우 매력적인 해양문화공간을 조성할 수 있을 것이다. 이에 본 연구는 중죽도와 연결된 매립지을 활용하여 해양문화공간을 조성하는 방안을 제시하고자 한다.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.716-724
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• 2008

In the case of subsea tunnels, hydro-mechanical coupled analysis is necessary for an exact design and construction. The consideration of the overstretched ground condition is also required because they are usually located at the great depth unlike the usual tunnels. Many researches have been performed on the estimation of relaxed rock mass height. However, there have been no researches on the estimation of relaxed rock mass height under overstretched ground conditions. In this study, therefore, hydro-mechanical coupled analyses were performed under the overstressed ground conditions and the relaxed rock mass heights were estimated based on the contour of the local safety factor around a tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.201-220
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• 2023

Power cable tunnels is one of the underground structures meant for electricity transmission and are constructed using shield TBM method when transitting across urban and subsea regions. With the increasing shaft depth for tunnels excavation when the shield TBM excavated the rock mass, the review of selecting closed-type shield TBM in rocks becomes necessary. A simplified shield TBM design method is also necessary based on conventional geotechnical survey results. In this respect, design method and related design program are developed based on combined results of full-scale tests, considerable amount of accumulated TBM data, and numerical simulation results. In order to validate the program results, excavation data of a completed power cable tunnel project are utilized. Thrust force, torque, and power of shield TBM specification are validated using Kernel density concept which estimates the population data. The robustness of design expertise is established through this research which will help in stable provision of electricity supply.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.133-143
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• 2015

Gas hydrate is a solid substance composed of natural gas constrained in water molecules under low temperature and high pressure conditions. The existence of hydrates has been reported to be world-widely distributed, mainly at permafrost and deep ocean floor. Test productions of small amount of natural gas from the on-shore permafrost have been accomplished in U.S.A and Canada, but, world-first and the only production case from off-shore hydrate bearing sediments was in Nankai trough, Japan. In this study, we introduce key technologies in gas production from hydrates by analyzing the Japanese off-shore gas production project in Nankai trough in terms of depressurization- induced dissociation so as to utilize planned domestic gas production test in Ulleung basin.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.161-172
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• 2014

An earth pressure balanced shield TBM with the diameter of 4.4 m was designed and manufactured for a subsea discharge tunnel excavation. Its cutterhead was designed to be optimized for the strongest rock mass condition in the tunnel alignment, and then the applicability of the refurbished shield TBM was validated for its maximum capacity. Especially, the maximum cutter penetration depth for the strongest rock mass condition should be kept to be below 7 mm/rev in order to satisfy the allowable capacities of the shield TBM. From the analysis of TBM advance data, approximately 95% of field data showed the cutter penetration depth below 7 mm/rev. In addition, it was certified that the acting forces of every disc cutter, TBM thrust and torque during TBM driving were within the allowable capacities of the shield TBM and its disc cutters. When real acting forces of the disc cutters in the field were compared with those predicted by the CSM model, they showed the close relationships with each other even though the predictions by the CSM model were approximately 22~25% higher than field data.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.825-831
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• 2006

This research does by purpose that present safe navigation plan for ships during doing dredging construction with dredger crossing waterway of Gadeok Dredging operations need to build sunken tunnel that cross the bottom of the sea under waterway of Gadeok for access road construction between Busan- Geoje. Accordingly, dredger must cross and dredge waterway of Gadeok fatally. There is possibility of marine accident of collision for latent danger situation of ships to navigate waterway of Gadeok relatively. Therefore, safe navigation plan of ship is groped in reply and its countermeasure is presented. Firstly, navigating traffic in daytime was forecasted less than 20% of its maximum capacity through estimating the traffic volume and traffic congestion The proposal was presented to execute dredging operations in three-step and to establish temporary waterway after reviewing waterway design principles. The role of VTS center was emphasized in the new Busan Port, lastly.

• New & Renewable Energy
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• v.7 no.4
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• pp.37-41
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• 2011

This paper presents a Combined solar-wave Power Generation (CPG) concept that the CPG unit is maintained as buoyant at the level of sea water and it is also supported by a submerged tunnel, with the aim of supplying emergency electric power during the station blackout events of nuclear power plants. The CPG concept has been motivated from the 2011 Fukushima-Daiichi Accidents due to the loss of both offsite AC power and emergency diesel power caused by natural hazards such as earthquake and tsunami. The CPG is conceptualized by applying different types and different sites for emergency power generation, in order to reduce common cause failures of emergency power suppliers due to natural hazards. Thus, the CPG can provide a new mean for supplying emergency electric power during station blackout events of nuclear power plants. For this application, the CPG requirements are described with a typical configuration at the ocean side of a submerged tunnel.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.111-116
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• 2008

Since the hydraulic fracturing field testing method was introduced first to Korean geotechnical engineers in 1994, there have been lots of progresses in a hardware system as well as an interpretation tool. The hydrofracturing system of first generation was the pipe-line type, and it has been developed to a wire-line system at their second generation. The current up-to-date system is more compact and is able to be operated by all-in-one system. With a progress in a hardware system, the software for analyzing in-situ stress regime has also been progressed. The shut-in pressure, which is the most ambiguous parameter to be obtained from hydrofracturing pressure curves, can now be acquired automatically from the various methods. While the hardware and software for hydrofracturing tests are being developed during the last decade, the author could accumulate the field test results which can cover the almost whole area of South Korea. Currently these field data are used widely in a feasibility study or a preliminary design step for tunnel construction in Korea. Regarding the difficulties in a site selection and a test performance for the in-situ stress measurement at an off-shore area, the in-situ stress regime obtained from the field experiences in the land area can be used indirectly for the design of a sub-sea tunnel. From the hydrofracturing stress measurements, the trend of magnitude and direction of in-situ stress field was shown identically with the geological information in Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1571-1580
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• 2008

Subsea tunnels that link land to island and among nations for transportation, efficient development of limited surface and pursuit of economic development should be designed to support pore water pressure on the lining. It is generally constructed in the bed rock of the sea bottom. When the tunnel excavation face meets fractured-zones below sea bottom, collapse may occur due to an increase of pore water pressure and large inflow. Such an example can be found in the Norwegian subsea tunnel experiences in 1980's. In this study hydraulic behavior of tunnel heading is investigated using numerical method based on the collapse of Norwegian subsea tunnel. The effect of pore water pressure and inflow rate were mainly concerned. Horse-shoe shaped model tunnel which has 50 m depth from the sea bottom is considered. To evaluate hydraulic performance, parametric study was carried out for varying relative permeability. It is revealed that pore water pressure has increased with an increase of sea depth. Especially, at the fractured-zone, pore water pressure on the lining has increased significantly. Inflow rate into tunnel has also increased correspondingly with an increase in sea depth. S-shaped characteristic relation between relative permeability and normalized pore water pressure was obtained.