• Title/Summary/Keyword: 터널복공

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Analysis of the Structural Behaviors of Tunnel Linings in Joomunjin Standard Sand by Centrifugal Model Tests (원심모형실험에 의한 사질토 지반내 터널 복공의 역학적 거동에 관한 연구)

  • 김택곤;김영근;박중배;이희근
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.10a
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    • pp.161-168
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    • 1999
  • A series of centrifuge model tests were performed in order to investigate the behaviors of various tunnel linings. A 1/100-scaled aluminum and hydrostone horseshoe tunnel linings with a radius km, height km were buried in a depth of C/D=3 with dry Joomunjin standard sand, the relative density of which was 86%. Bending moments and thrusts along the tunnel circumference were measured by 12 strain gages. Earth pressures in soil and on lining were estimated by pressure transducers, ground surface settlements at center and edges by using LVDTs. Average Ko(coefficient of earth pressure at rest) was 0.39 for the model sand. The structural behaviors of lining depended on its damaged conditions. But, as a rule, on the crown, the tensile circumferential strain of lining occurred at the inner surface, and the compressive at the outer surface, then positive bending moment was created at the crown. The circumferential strain of the inner surface on the springline was tensile, and the outer compressive, so negative bending moment was measured at the springline. For hydrostone linings, cracks initiated at the inner surface on the crown, and the outer on the springline over average 40g.

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Mechanical Properties of a Lining System under Cyclic Loading Conditions in Underground Lined Rock Cavern for Compressed Air Energy Storage (복공식 지하 압축공기에너지 저장공동의 내압구조에 대한 반복하중의 역학적 영향평가)

  • Cheon, Dae-Sung;Park, Chan;Jung, Yong-Bok;Park, Chul-Whan;Song, Won-Kyong
    • Tunnel and Underground Space
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    • v.22 no.2
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    • pp.77-85
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    • 2012
  • In a material, micro-cracks can be progressively occurred, propagated and finally lead to failure when it is subjected to cyclic or periodic loading less than its ultimate strength. This phenomenon, fatigue, is usually considered in a metal, alloy and structures under repeated loading conditions. In underground structures, a static creep behavior rather than a dynamic fatigue behavior is mostly considered. However, when compressed air is stored in a rock cavern, an inner pressure is periodically changed due to repeated in- and-out process of compressed air. Therefore mechanical properties of surrounding rock mass and an inner lining system under cyclic loading/unloading conditions should be investigated. In this study, considering an underground lined rock cavern for compressed air energy storage (CAES), the mechanical properties of a lining system, that is, concrete lining and plug under periodic loading/unloading conditions were characterized through cyclic bending tests and shear tests. From these tests, the stability of the plug was evaluated and the S-N line of the concrete lining was obtained.

Feasibility Study of Underground LNG Storage System in Rock Cavern (LNG 지하공동 비축시스템의 타당성분석)

  • Chung, So-Keul;Han, Kong-Chang;Park, Eui-Seob
    • Tunnel and Underground Space
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    • v.16 no.4 s.63
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    • pp.296-306
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    • 2006
  • It is difficult to solve problems regarding the adjustment on demand and supply of LNG due to seasonal variations of domestic demand of LNG, a discordance among import pattern and limits of storage facilities and so on. Also, there may be instability in LNG supply due to chances of accidents at LNG producing areas. Therefore, it is very important to secure large LNG storage facilities and to stabilize LNG supply management on a long term basis. The objective of this study is to examine the real-scale applicability of a lined underground rock storage system, which have been verified by a successful operation of the Daejeon LNG pilot plant. The new technology has many advantages of better economy, safety and environment protection, for above-ground and in-ground storage systems. The results of this study may promote the first ever real scale underground LNG storage system in a rock cavern.