• Title, Summary, Keyword: 터널 형상

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Investigation of soil behaviour due to excavation below the grouped pile according to shape of tunnel station (터널 정거장 형상에 따른 군말뚝 하부 굴착 시 지반거동 연구)

  • Kong, Suk-Min;Oh, Dong-Wook;Lee, Jong-Hyen;Lee, Yong-Joo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.1
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    • pp.83-97
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    • 2018
  • Tunnels are widely used for special purposes including roads, railways and culvert for power transmission, etc. Its cross-section shape is determined by uses, ground condition, environmental or economic factor. Many papers with respect to behaviours of adjacent ground and existing structure tunnelling-induced have been published by many researchers, but tunnel cross-section have rarely been considered. A collapse of tunnel causes vaster human and property damage than structures on the ground. Thus, it is very important to understand and analyse the relationship between behavoiurs of ground and cross-section type of tunnel. In this study, the behaviour of ground due to tunnel excavation for underground station below the grouped pile supported existing structure was analysed through laboratory model test using a trap-door device. Not only two cross-section types, 2-arch and box, as station for tunnel, but also, offset between tunnel and grouped pile centre (0.1B, 0.25B, 0.4B) are considered as variable of this study. In order to measure underground deformation tunnelling-induced, Close Range Photogrammetry technique was applied with laboratory model test, and results are compared to numerical analysis.

A Study for the Stability Investigation of Three Parallel Tunnels Using Scaled Model Tests (삼병렬 터널의 안정성 검토를 위한 모형실험 연구)

  • Kim, Jong-Woo;Bae, Woo-Seok
    • Tunnel and Underground Space
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    • v.18 no.4
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    • pp.300-311
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    • 2008
  • In this study, scaled model tests were performed to investigate the stability of three parallel tunnels. Seven types of test models which had respectively different pillar widths, tunnel sectional shapes, support conditions and ground conditions were experimented, where crack initiating pressures and deformation behaviors around tunnels were investigated. In order to evaluate the effect of pillar widths on stability, various models were experimented. As results, the models with shallower pillar widths proved to be unstable because of lower crack initiating pressures and more tunnel convergences than the models with thicker pillar widths. In order to find the effect of tunnel sectional shape on stability, the models with arched, semi-arched and rectangular tunnels were experimented. Among them rectangular tunnel model was the most unstable, where the arched tunnel model with small radius of roof curvature was more stable than semi-arched one. The model with rockbolt showed higher crack initiating pressure and less roof lowering than the unsupported model. The deformation behaviors of tunnels in the anisotropic ground model were quite different from those in the isotropic ground model. Futhermore, the results of FLAC analysis were qualitatively coincident with the experimental results.

3D Tunnel Shape Fitting by Means of Laser Scanned Point Cloud (레이저 스캐닝 측점군에 의한 터널 3차원 형상의 재현)

  • Kwon, Kee Wook;Lee, Jong Dal
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.4D
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    • pp.555-561
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    • 2009
  • In lieu of section profile data, a fitting of the bored tunnel shape is more significant confirmation for maintenance of a tunnel. Before the permit on the completion of a tunnel, deformation of the completed tunnel with respect to the design model are considered. And deformation can be produced at continuously along the entire of the tunnel section. This study firstly includes an analysis of algebraic approach and test it with an observed field data. And then a number of methods, line search method, genetic algorithm, and pattern search methods, are compared with the 3D tunnel shape fitting. Algebraic methods can solve a simple circular cylinder type as like a railway tunnel. However, a more complex model (compound circular curve and non circular) as like a highway tunnel has to be solved with soft computing tools in the cause of conditional constraints. The genetic algorithm and pattern search methods are computationally more intensive, but they are more flexible at a complex condition. The line search method is fastest, but it needs a narrow bounds of the initial values.

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Design on the large section of station tunnel under shallow overburden (저토피고 대단면 정거장터널의 설계)

  • Jeong, Yun-Young;Choi, Hae-Joon;Kim, Byung-Ju;Yu, Bong-Won;Kim, Yong-Il;Oh, Sung-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.9 no.2
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    • pp.171-182
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    • 2007
  • For minimizing the effect on the focus of civil traffic and environment conditions related to the excavation at the traffic jamming points, an underground station tunnel was planned with 35.5 m in length and bigger area than $200\;m^2$ in sedimentary rock mass. It faced the case that the overburden was just under 13 m. Not based on a pattern design but on the case histories of similar projects and arching effect, the design of large section tunnel under shallow overburden was investigated on three design subjects which are shape effect on the section area, application method of support pressure, and supporting and tunnel safety. According to the mechanical effect from section shape, a basic design and a preliminary design was obtained, and then supporting method of large section was planned by the supporting of NATM and a pipe roof method for subsidence prevention and mechanical stability. From the comparative study between both designs, it was found that the basic design was suitable and acceptable for the steel alignment of tunnel lining, safety and the design parameter restricted by the limit considered as partition of the excavation facilities. Through the analysis result of preliminary design showing the mechanical stability without stress concentration in tunnel arch level, it also was induced that shape effect of the large section area and yielding load obtained from deformation zone in the surrounding rock mass of tunnel have to be considered as major topics for the further development of design technique on the large section tunnel.

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Stability Analysis of Highway Tunnel and Railway Tunnel According to Section Shape (단면형상 차이에 따른 고속도로 터널과 철도터널의 안정성 분석)

  • Kim, Jae-Kyoung;Lee, Bum-Jun;Lee, Song
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.4
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    • pp.107-115
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    • 2009
  • The number of railway tunnel design is increasing recently compare to a great number of highway tunnel design which had increased with a lot of highway construction in the 70's and 80's. Therefore, there is more or less difference of time between highway tunnel and railway tunnel. In this paper, numerical analysis on two kinds of tunnels, such as two-forked road highway ventilation tunnel and double track railway tunnel with 4.3m of center line, in cases of with support materials condition and without support materials condition were conducted. Finally, stability of two kinds of tunnels were compared and analyzed through comparing of principal stresses and deviator stresses in the near base rock of tunnels using results of numerical analysis.

Key block analysis method for observational design and construction method in tunnels (터널의 정보화 설계시공을 위한 키블럭 해석기법)

  • Hwang, Jae-Yun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.12 no.3
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    • pp.275-283
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    • 2010
  • Recently, the observational design and construction method in tunnels has been becoming important. Rock masses include various discontinuities such as joints, faults, fractures, bedding planes, and, cracks. The behavior of tunnels in hard rocks, therefore, is generally controlled by various discontinuities. In this study, a new key block analysis method for observational design and construction method in tunnels is proposed, and then applied to the actual tunnel with a super-large cross-section. The proposed analysis method considers finite persistence of discontinuities. The new analysis method can handle concave and convex shaped blocks. To demonstrate the applicability of this key block analysis method for observational design and construction method in tunnels, the analysis results are examined and compared with those of the conventional method.

A numerical study for initial elastic displacement at tunnel side-wall due to configuration of the tunnel excavation (굴착단면 형상에 따른 터널 초기탄성변위의 수치해석적 연구)

  • Kim, Sang-Hwan;Jung, Hyuk-Il;Lee, Min-Sang
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.4 no.3
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    • pp.175-184
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    • 2002
  • Ground reaction curve is very useful information for estimating the installation time of the tunnel support. The ground reaction curve can be estimated by analytical closed form solutions derived in case of circular section and isotropic stress condition. The nature of the ground reaction, however, depends significantly on tunnel configurations. Nevertheless, few purely analytical and experimental studies of this problem due to tunnel configurations appear to have been carried out. Therefore, it is necessary to investigate the influence of tunnel configurations in order to use simply in practical design. This paper describes a numerical study for the intial elastic displacement in the ground reaction curve due to configuration of tunnel excavation. In order to evaluate the applicability of analytical closed form solution in practical design, the parametric studies were carried out by numerical analysis in elastic tunnel behaviour. In the studies, S value, namely configuration factor, defined as the ratio between tunnel height (b) and width (a), varies between 0.5 and 3.0, initial ground vertical stress varies between 5~30 MPa for each S values. The results indicated that the self-supportability of ground is larger in the ground having low S value. It, however, is suggested that the applicability of closed form solution may not be adequate to determine directly the installation time of the support and self-supportability of ground. It should be necessary to perform the additional numerical analysis.

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장대터널의 화재위험과 인명안전 대책

  • Son, Bong-Se
    • 방재와보험
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    • pp.12-18
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    • 2006
  • 일반적으로 긴 일방향성의 형상을 가진 터널의 구조는 화재 및 각종 사고 발생시 정보나 피난동선의 확보가 제한되어 인명피해 우려가 높은 특수한 방호공간이다. 따라서 터널의 화재 위험 및 관리실태를 점검하여 과학적이고 체계적인 종합 안전 대책을 수립하여야 한다.

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A stability study of deep and double-deck tunnels considering shape and reinforcing method of an enlarged section by using numerical analyses (수치해석을 이용한 대심도 복층터널의 확폭단면 형상 및 보강방법에 대한 안정성 연구)

  • You, Kwang-Ho;Jin, Su-Hyun;Kim, Young-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.1
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    • pp.41-56
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    • 2017
  • Recently, the necessity of deep and double-deck tunnels has been grown day by day due to the increase of traffic volume at metropolitans and thus the study on the divergence of those tunnels becomes required. Therefore sensitivity analyses were conducted with FLAC 2D program by selecting ground condition, coefficient of lateral pressure, support pattern, and depth of rock cover as parameters. Ultimately, this study is to find the optimal shape and support method of a diverged section. As the results of this study, it turned out that the box type gave higher stability of the section than arch type unlike the general thought. It can be explained that the arch type has about 30% bigger excavation area than the box type. When the ground conditions are poor, steel pipe grouting reinforcement gives higher stability than rockbolt reinforcement, but its thickness and range do not give a great influence on the stability of the enlarged section.

Soil-Tunnel Interaction and Isolation Effect During Earthquakes (지진시 지반-터널 상호작용 및 면진효과)

  • 김대상
    • Journal of the Earthquake Engineering Society of Korea
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    • v.4 no.3
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    • pp.107-115
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    • 2000
  • 충적지반에 건설된 원형 단면을 갖는 터널은 지진시에 지반의 전단 변형의 영향을 받아 좌우교차로 경사진 타원형상의 변형을 반복한다. 본 논문에서는 이 특별한 진동모드를 이용하여 지반-터널계의 상호작용 및 면진 효과가 검토되었다. 지반과 터널의 경계가 완전히 결합되어 있는 경우에 대한 지반 -터널계의 상호작용 효과 및 지하 구조물의 지진피해를 줄이는 한가지 방법으로써 터널 주위를 면진재로 피복하는 방법에 대한 면진효과가 토론되었다. 그 결과 면진재의 포아송비를 작게 하거나 지반과 면진재의 전단탄성계수의 비를 증가시킴으로서 면진 효가가 증가함을 알 수 있었다.

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