• Title, Summary, Keyword: Tunnel behavior

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Behavior of Tunnel Face Reinforced with Horizontal Pipes (수평보강재로 보강된 터널 막장의 거동)

  • 유충식;신현강
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.185-192
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    • 1999
  • This paper presents the results of a parametric study on the behavior of tunnel face reinforced with horizontal pipes. A three-dimensional finite element model was adopted in this study to capture the three-dimensional nature of tunnel face behavior under various boundary conditions. A parametric study was peformed on a wide range of boundary conditions with emphasis on the effect of reinforcing layouts on the deformation behavior of tunnel face. The results of analysis such as tunnel face deformation behavior under various conditions were thoroughly analyzed, and a database for the behavior of tunnel face under different reinforcing conditions was established for future development of a semi-empirical design/analysis method for the tunnel face reinforcing technique. The results indicated that there exits an optimum reinforcing layout for a given tunnel condition, which must be selected with due consideration of tunnel geometry and ground condition.

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Evaluation of Behavior of Jointed Concrete Pavement Considering Temperature Condition in a Tunnel by Finite Element Method (구조해석을 통한 터널내 줄눈 콘크리트 포장의 거동분석)

  • Ryu, Sung Woo;Park, JunYoung;Kim, HyungBae;Lee, Jaehoon;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.18 no.2
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    • pp.19-27
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    • 2016
  • PURPOSES: The behavior of a concrete pavement in a tunnel was investigated, based on temperature data obtained from the field and FEM analysis. METHODS: The concrete pavement in a tunnel was evaluated via two methods. First, temperature data was collected in air and inside the concrete pavement both outside and inside the tunnel. Second, FEM analysis was used to evaluate the stress condition associated with the slab thickness, joint spacing, dowel, and rock foundation, based on temperature data from the field. RESULTS : Temperature monitoring revealed that the temperature change in the tunnel was lower and more stable than that outside the tunnel. Furthermore, the temperature difference between the top and bottom of the slab was lower inside the tunnel than outside. FEM analysis showed that, in many cases, the stress in the concrete pavement in the tunnel was lower than that outside the tunnel. CONCLUSIONS : Temperature monitoring and the behavior of the concrete pavement in the tunnel revealed that, from an environmental point of view, the condition in the tunnel is advantageous to that outside the tunnel. The behavior in the tunnel was significantly less extreme, and therefore the concrete pavement in the tunnel could be designed more economically, than that outside the tunnel.

Cases of Tunnel Monitoring of Anisotropic/Heterogeneous Rock Masses (이방성/비균질 암반의 터널 계측 사례 분석)

  • Kim, Chang-Yong;Hong, Sung-Wan;Kim, Kwang-Yeom;Baek, Seung-Han
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1299-1306
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    • 2005
  • The introduction of geodetic methods of absolute displacement monitoring in tunnels has improved the value of the measurements significantly. By using this method, structurally controlled behavior and influences of an anisotropic rock mass can be determined and the excavation and support adjusted accordingly. In this study cases of tunnel monitoring in anisotropic/heterogeneous rock masses are analyzed, and various anisotrpic behavior of tunnel can be estimated. Because rock anisotropy and heterogeneity can have great influence on tunnel behavior, tunnel design considering rock anisotropy and heterogeneity is needed. Also under construction, feedback must be performed by using face mapping and monitoring to prevent over-deformation and tunnel collapse.

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Behavior and Performance Evaluation of a Concrete Pavement Considering the Temperature Condition in a Tunnel (터널내 온도조건을 고려한 콘크리트 포장의 거동 및 성능 평가)

  • Ryu, Sung Woo;Park, JunYoung;Kim, HyungBae;Lee, Jaehoon;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.18 no.2
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    • pp.11-18
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    • 2016
  • PURPOSES: This paper investigates behavior and performance of concrete pavement in tunnel based on temperature data from field. METHODS : In this study, there are 4 contents to evaluate concrete pavement in tunnel, First, Comparison for distress was conducted at outside, transition, and inside part of tunnel. Secondly, temperature data was collected in air and inside concrete pavement in outside and inside tunnel. Thirdly, FEM analysis was performed to evaluate stress condition, based on temperature data from field. Finally, performance prediction was done with KPRP program. RESULTS: From the distress evaluation, failure of inside tunnel was much less than it of outside tunnel, Temperature change in tunnel was less than out side, and also it was more stable. According to result of FEM analysis, both curling stress status of inside tunnel was lower than it of outside tunnel. Based on KPRP program analysis, performance of inside tunnel was longer than outside. CONCLUSIONS : Through all study about behavior and performance of concrete pavement in tunnel, condition in tunnel has more advantages from environmental and distress point of view. Therefore, performance of inside tunnel was better than outside.

Effect of construction sequence on three-arch tunnel behavior-Numerical investigation

  • Yoo, C.;Choi, J.
    • Geomechanics and Engineering
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    • v.15 no.3
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    • pp.911-917
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    • 2018
  • This paper concerns a numerical investigation on the effect of construction sequence on three-arch (3-Arch) tunnel behavior. A three-arch tunnel section adopted in a railway tunnel construction site was considered in this study. A calibrated 3D finite element model was used to conduct a parametric study on a variety of construction scenarios. The results of analyses were examined in terms of tunnel and ground surface settlements, shotcrete lining stresses, loads and stresses developed in center column in relation to the tunnel construction sequence. In particular, the effect of the side tunnel construction sequence on the structural performance of the center structure was fully examined. The results indicated that the load, thus stress, in the center structure can be smaller when excavating two side tunnels from opposite direction than excavating in the same direction. Also revealed was that no face lagging distance between the two side tunnels impose less ground load to the center structure. Fundamental governing mechanism of three-arch tunnel behavior is also discussed based on the results.

Study on seismic behavior and seismic design methods in transverse direction of shield tunnels

  • He, Chuan;Koizumi, Atsushi
    • Structural Engineering and Mechanics
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    • v.11 no.6
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    • pp.651-662
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    • 2001
  • In order to investigate the seismic behavior and seismic design methods in the transverse direction of a shield tunnel, a series of model shaking table tests and a two-dimensional finite element dynamic analysis on the tests are carried out. Two kinds of static analytical methods based on ground-tunnel composite finite element model and beam-spring element model are proposed, and the validity of the static analyses is verified by model shaking table tests. The investigation concerns the dynamic response behavior of a tunnel and the ground, the interaction between the tunnel and ground, and an evaluation of different seismic design methods. Results of the investigation indicate that the shield tunnel follows the surrounding ground in displacement and dynamic characteristics in the transverse direction; also, the static analytical methods proposed by the authors can be used directly as the seismic design methods in the transverse direction of a shield tunnel.

A Study on the Behavior of a Closely-Spaced Tunnel by Using Scaled Model Tests (축소모형실험을 통한 근접터널의 거동에 관한 연구)

  • Ahn, Hyun-Ho;Choi, Jung-In;Lee, Seok-Won;Shim, Seong-Hyeon
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.189-198
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    • 2008
  • Lots of roadway tunnel have been almost constructed in forms of closely-spaced tunnel in korea. If closely-spaced tunnel is not constructed at a sufficient distance between tunnels, the problem of stability can occur. However, the case that can not secure a sufficient distance between tunnels can occur due to a difficulty in buying a lot and an issue of popular complaint and environmental disruption. Generally, tunnels are not influenced by each other when a center distance between tunnels is two times longer than tunnel diameter under the complete elastic ground and five times under the soft ground. In this study, the scaled model tests of closely-spaced tunnel by using homogeneous material were performed and induced displacements were measured around the tunnel openings during excavation. The influence of distance between tunnels on the behavior of closely-spaced tunnel was investigated.

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Reduced-Scale Model Tests on the Behavior of Tunnel Face Reinforced with longitudinal reinforcements (수평보강재로 보강된 터널 막장의 거동에 관한 축소 모형실험)

  • 유충식;신현강
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.79-86
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    • 2000
  • This paper presents the results of a parametric study on the behavior of tunnel face reinforced with horizontal pipes. A series of reduced-scale model tests was carried out to in an attempt to verify previously performed three-dimensional numerical modeling and to investigate effects of reinforcement layout on the tunnel face deformation behavior The results of model tests indicate that the tunnel face deformation can significantly reduced by pre-reinforcing the tunnel face with longitudinal members and thus enhancing the tunnel stability. In addition, the model tests results compare fairly well with those from the previously performed three-dimensional finite element analysis. Therefore, a properly calibrated three dimensional model may effectively be used in the study of tunnel face reinforcing technique.

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The influence of model surface roughness on wind loads of the RC chimney by comparing the full-scale measurements and wind tunnel simulations

  • Chen, Chern-Hwa;Chang, Cheng-Hsin;Lin, Yuh-Yi
    • Wind and Structures
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    • v.16 no.2
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    • pp.137-156
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    • 2013
  • A wind tunnel test of a scaled-down model and field measurement were effective methods for elucidating the aerodynamic behavior of a chimney under a wind load. Therefore, the relationship between the results of the wind tunnel test and the field measurement had to be determined. Accordingly, the set-up and testing method in the wind tunnel had to be modified from the field measurement to simulate the real behavior of a chimney under the wind flow with a larger Reynolds number. It enabled the results of the wind tunnel tests to be correlated with the field measurement. The model surface roughness and different turbulence intensity flows were added to the test. The simulated results of the wind tunnel test agreed with the full-scale measurements in the mean surface pressure distribution behavior.

Analysis on the tunnel behavior characteristic in the excessive fractured zone distribution of rock area (파쇄대가 과대분포한 암반지역에서 터널의 거동특성에 관한 연구)

  • Park, Jae-Weon;Lee, Seung-Ho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.4
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    • pp.341-354
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    • 2016
  • This article is to apply the tunnel support system selected after comparatively analyzing of RMR and tunnel instrumentation between the tunnel behavior characteristic predicted through geotechnical investigations and the numerical analysis at the design stage and the properties deformation occurred at the construction stage. This attempt results from the behavior characteristic of the tunnel excavation ground shown differently in accordance with the ground quality and reinforcement method. This, therefore, provide the data and results analysed the actual decision RMR-crown settlement & convergence and reduction of material property of ground as parameters. Also, it's shown that the tunnel designer is able to predict tunnel behavior characteristic when designing in bedrock areas excessively distributed faults and fractured zones.