• Title, Summary, Keyword: Operating Subsea Tunnel

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The review about ultra long subsea tunnel design under high water pressure (고수압 초장대 해저터널에 관한 연구)

  • Jun, Duk-Chan;Kim, Ki-Lim;Hong, Eui-Joon;Kim, Chan-Dong;Lee, Young-Joon;Hong, Cheor-Hwa
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.6
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    • pp.829-843
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    • 2017
  • Subsea tunnel needs to be built over 50 km long to connect between nations and continents. However there are only 19 tunnels longer than 5 km until recently. And there is no history of constructing and operating tunnel longer than 50 km. In Korea, subsea tunnels with a length of more than 50 km are being planned, such as Korea~Japan, Korea~China, Honam~Jeju subsea tunnels. Because of the geographical conditions of Korea, most of these tunnels are inter-contry tunnels. So technology preemption for the subsea tunnel construction is getting more and more important. Most of these subsea tunnels are ultra-long tunnels under high water pressure conditions. So new technologies are required such as ventilation and disaster prevention of high-speed tunnels, securing of structural stability under high pressure conditions, and pressure reduction in high-speed conditions. These technologies are different from those of ground tunnels. Therefore, this paper describes the ultra-long subsea tunnel design under high water pressure of maximum 16 bars through the Honam (land) - Jeju (island) virtual subsea project. We proposed a reasonable solution to various problems such as securing structural stability in high pressure condition and ventilation disaster prevention system of ultra long-tunnel.

The development of a back analysis program for subsea tunnel stability under operation: transversal tunnel section (운영 중 해저 터널의 안정성 평가를 위한 역해석 프로그램 개발: 횡단방향)

  • An, Joon-Sang;Kim, Byung-Chan;Lee, Sang-Hyun;Song, Ki-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.2
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    • pp.195-212
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    • 2017
  • When back analysis is used for the assessment of an operating subsea tunnel safety in various measurement information such as stress, water pressure and tunnel lining and ground stiffness degradation, the reliable results within tolerable error rate can be obtained. By utilizing a commercial geotechnical analysis program FLAC3D, back analysis can be performed with a DEA which has already been successfully validated in previous studies. However, relative more time-consumption is the drawback of this approach. For this reason, this study introduced beam-spring model-based on FEM solver which uses less analysis time relatively. Beam-spring program capable of structural analysis of a circular tunnel section was developed by using Python language and combined with the built-DEA. From the measurement datum, expected to estimate the stability of an operation tunnel close to real-time.

The development of a back analysis program for subsea tunnel stability under operation: longitudinal direction (운영 중 해저 터널의 안정성 평가를 위한 역해석 프로그램 개발: 종단방향)

  • An, Joon-Sang;Kim, Byung-Chan;Moon, Hyun-Koo;Song, Ki-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.6
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    • pp.545-556
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    • 2016
  • If a back analysis is used in various measurement information for the estimation of an operating subsea tunnel safety, it is possible to obtain the results within efficient error rate. With such a commercial geotechnical analysis program as FLAC3D, back analysis is performed with a DEA which was validated in previous studies. However, there is a problem that is relatively a time-consuming analysis. For this reason, beam-spring model-based FEM solver which takes shorter relative analysis time, was developed by Python language, and then combined with the built-DEA. In order to consider the assessment of safety of an operation tunnel near real-time, a program for longitudinal direction tunnel was developed due to its relative easy development for analysis solver engine.

DEA optimization for operating tunnel back analysis (운영 중 터널 역해석을 위한 차분진화 알고리즘 최적화)

  • An, Joon-Sang;Kim, Byung-Chan;Moon, Hyun-Koo;Song, Ki-Il;Su, Guo-Shao
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.2
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    • pp.183-193
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    • 2016
  • Estimation of the stability of an operating tunnel through a back analysis is a difficult concept to analyze. Specially, when a relatively thick lining is constructed as in case of a subsea tunnel, there will be a limit to the use of displacement-based tunnel back analysis because the corresponding displacement is too small. In this study, DEA is adopted for tunnel back analysis and the feasibility of DEA for back analysis is evaluated. It is implemented in the finite difference code FLAC3D using its built-in FISH language. In addition, the stability of a tunnel lining will be evaluated from the development of displacement-based algorithm and its expanded algorithm with conformity of several parameters such as stress measurements.