• Title/Summary/Keyword: 콘크리트 라이닝

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A Study on the Behavior of Cut and Cover Tunnel according to the Excavation Plane by Numerical Analysis (굴착사면 변화에 따른 복개 터널구조물의 역학적 거동에 관한 수치해석적 연구)

  • Bae, Gyu-Jin;Lee, Seok-Won;Lee, Gyu-Phil;Park, Si-Hyun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.4 no.1
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    • pp.79-90
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    • 2002
  • The structural analysis such as rigid frame analysis has been used for the design of cut and cover tunnel due to its simplicity and convenience. This analysis, however, could not account for the geometrical factors such as interface elements, slope of excavation plane, distance between lining and excavation plane, etc. To develop the analysis technique and design technology for the cut and cover tunnel, in this study, the numerical analyses considering not only geometrical but geotechnical factors are conducted. Especially, the effects on the mechanical behaviors of cut and cover tunnel due to the slope of excavation plane and the distance between lining and excavation plane are mainly focused in this study.

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A Case Study on Buckling Incidents of Steel Liner under External Water Pressure (외수압에 의한 강관 라이닝 좌굴 사례 연구)

  • Chung, Kyujung;Chung, Kyungmun;Shin, Hyohee;Kim, Daeho
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.12
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    • pp.13-20
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    • 2011
  • The main objective of this paper is finding the influence factors and their degree of importance to steel liner's safety by investigating and evaluating the buckling incidents of steel tunnel liner under external water pressure. The study was based on the detailed investigation to the design conditions and incident shapes at 2m diameter waterway tunnel with a partially buckled internal steel liner and concrete backfilled lining as the raw water transmission pipe line of regional water supply project. Appropriate buckling theory capable of applying this incident points was selected by referring the existing literature and compared with the results of investigation. Also, hydrogeological characteristics of this site on buckling pressure was evaluated. The result of this study was shown that both the hydrogeological characteristics of upper geologic layers and proper tunnel construction are important factors on buckling at steel liner, and hydraulic gradient level should be decided according to the hydrogeological characteristics. This incident case analysis on steel liner of pressurized waterway tunnel was expected to provide more information for realizing the problems and improvements at each design, construction and maintenance stages.

Evaluation on the Thermal Damage of Steel Embedded in Concrete in Tunnel Fire(Modified Hydrocarbon Curve) (터널 화재(Modified Hydrocarbon Curve)시콘크리트에 매입된 강재의 열적 손상 평가)

  • Park, Kyoung-Hoon;Kim, Heung-Yeol;Kim, Hyung-Jun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.485-488
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    • 2008
  • Fire intensity in tunnel fire is very severe, which might cause the spalling on the surface of shotcrete and concrete lining exposed to the heat as well as rapidly-reducing stress due to heat transfer by steel material such as anchor embedded in tunnel which plays the critical role in securing the stability of the tunnel. In this study, a fire test to identity the heat intensity(Modifired Hydrocarbon Curve) and the fire resistance of steel materials embedded as parameters, was carried out. And the evaluation to identify the thermal damage, which was based on critical temperature range for thermal damage of steel materials determined according to the road tunnel fire resistance standard established by ITA(International Tunneling Association).

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A Study on the Expansion Joint of Concrete Lining and Duct in a Tunnel (터널 콘크리트 라이닝 및 공동구 신축이음 설치방안에 관한 연구)

  • Son, Moorak;Park, Yangheum;Park, Yunjae;Kim, Jaegyoun;Yoon, Jongcheol
    • Journal of the Korean Geotechnical Society
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    • v.31 no.3
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    • pp.39-50
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    • 2015
  • The installation of the expansion joints in a tunnel concrete lining and duct would minimize the cracking at the location of structural shape and stiffness change, differential settlement, big temperature change, and so on. However, it is difficult to determine the required spacing of the expansion joint in a tunnel concrete lining and duct quantitatively because the spacing is influenced by temperature change, structure construction condition, ground-structure interaction, and etc. Nevertheless, a highway specification (Korea Expressway Corporation, 2012) or a road design manual (Ministry of Land, Transport and Maritime Affairs, 2010) specifies that the expansion joint spacing in a tunnel concrete lining should be installed uniformly smaller than 25 m from the tunnel portals to 50 m inside of a tunnel and elsewhre 20-60 m in a tunnel (because there is no specifcation for a duct it is assumed that a duct follows the specfication of lining). This specification results in several construction and economic problems in relation with a tunnel construction. Accordingly, in order to minimize the problems, this study analyzed both domestic and foreign design standards and specifications. In addition, field test, theoretical and numerical analyses were carried out in relation to the expansion joint in a tunnel lining and duct. The purpose of this study is to reestabilish a criterion for installing the expansion joint in a tunnel concrete lining and duct.

Fire resistance assessment of segment lining with PP fiber amount (PP섬유 혼입량에 따른 세그먼트 라이닝의 화재저항성 평가)

  • Choi, Soon-Wook;Kang, Tae-Ho;Lee, Chulho;Kim, Hae Song;Ahn, Byoungcheol;Chang, Soo-Ho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.23 no.5
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    • pp.303-314
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    • 2021
  • With the high quality/high stiffness/high strength of segment lining, segment lining is increasingly used as the final lining of the tunnel. Precast concrete lining has higher quality and strength than field concrete. Paradoxically, this contributes to greater damage to concrete in the event of a fire in a tunnel. In this study, tests were conducted to determine the fire resistance performance of segment linings according to fiber content in fire resistance methods using synthetic fibers such as PP fibers. As a result, it was confirmed that fire resistance performance required by the relevant project can be secured when using 1.5 kg/m3 of PP fiber. In addition, comparison of the results of PP fibers with PET, a similar synthetic fiber, showed better fire resistance performance than when PP fibers were used.