• 제목/요약/키워드: 쉴드터널

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Evaluation of Fire-induced Damage for Shield Tunnel Linings Subjected to High Temperatures (고온에 노출된 쉴드터널 라이닝의 손상평가)

  • Lee, Chang Soo;Kim, Yong Hyok;Kim, Young Ook
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.4
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    • pp.1-8
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    • 2012
  • The aim of this study is to evaluate fire-induced damage for shield tunnel linings. Full-scale fire test was conducted to evaluate fire-induced damage. Residual compressive strength was measured on the core samples of shield tunnel lining subjected to high temperatures. Heating temperature was predicted by XRD and TG analysis. As a result, Strength degradation of concrete with temperatures can be evaluated by residual compressive strength of core samples. In addition, residual compressive strength can be estimated by previous studies if heating temperature is exactly predicted. It is possible that heating temperature is predicted by XRD and TG analysis at $450^{\circ}C$. For more accurate prediction of heating temperature it should be performed both instrumental analysis and analytical methods with temperatures ranging from $400{\sim}600^{\circ}C$.

The study on the effect of fracture zone and its orientation on the behavior of shield TBM cable tunnel (단층파쇄대 규모 및 조우 조건에 따른 전력구 쉴드 TBM 터널의 거동 특성 분석)

  • Cho, Won-Sub;Song, Ki-Il;Kim, Kyoung-Yul
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.4
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    • pp.403-415
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    • 2014
  • Recently, the temperature rise in the summer due to climate change, power usage is increasing rapidly. As a result, power generation facilities have been newly completed and the need for ultra-high-voltage transmission line for power transmission of electricity to the urban area has increased. The mechanized tunnelling method using a shield TBM have an advantage that it can minimize vibrations transmitted to the ground and ground subsidence as compared with the conventional tunnelling method. Despite the popularity of shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Thus, in this study, the effect of fractured zone ahead of tunnel face on the mechanical behavior of the shield TBM cable tunnel is investigated. In addition, it is intended to compare the behavior characteristics of the fractured zone with continuous model and applying the interface elements. Tunnelling with shield TBM is simulated using 3D FEM. According to the change of the direction and magnitude of the fractured zone, Sectional forces such as axial force, shear force and bending moment are monitored and vertical displacement at the ground surface is measured. Based on the stability analysis with the results obtained from the numerical analysis, it is possible to predict fractured zone ahead of the shield TBM and ensure the stability of the tunnel structure.

Waterproofing performance evaluation according to the number of layer for shield TBM segment hydrophilic rubber waterstop (쉴드 TBM 세그먼트 지수재의 배열수 변화에 따른 방수성능 평가)

  • Ham, Soo-Kwon;Jung, Hoon;Kim, Beom-Ju;Jeong, Kyeong-han;Lee, Seok-Won
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.1
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    • pp.47-58
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    • 2020
  • The interest in the use of shield TBM (Tunnel Boring Machine) on the tunnel excavation has been increased rapidly in Korea. The shield TBM tunnel is generally designed as non-drainage tunnel. Consequently, if water leakage through the segment joints happens, big problems on the usage and stability of tunnel can be occurred. In this study, the variation of waterproof capacity of hydrophilic rubber waterstop by the construction error and excessive displacement of segment was studied. In particular, the waterproof capacity of each of single and double layer arrangements of hydrophilic rubber waterstop was examined to verify the efficiency of the double layer arrangement. The test results show that the single layer and double layer hydrophilic rubber waterstop showed the same waterproof performance. hydrophilic rubber waterstop has favorable on the offset, however unfavorable on the gap.

Development of performance assessment criterion for structures of shield TBM tunnel (쉴드 TBM 터널의 구조물 성능 평가 기준 개발)

  • Seong, Joo-Hyun;Lee, Yu-Seok;Hong, Eun-Soo;Byun, Yo-Seph
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.5
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    • pp.553-561
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    • 2015
  • In this study, the performance assessment criterion for reasonable maintenance of shield TBM tunnel was presented. The performance assessment items such as crack, leakage, breakage, spalling, exfoliation/detachment, efflorescence, quality condition, exposure of steel, carbonation, faulting step, bolts condition, drainage condition, ground condition, contact section condition and conduit condition were selected by analyzing domestic and foreign performance assessment criterions and investigating segment lining deterioration cases through the site investigation and in-depth inspection analysis result on the shield TBM tunnel. In addition, the reasonable weight using AHP (Analytic Hierarchy Process) were estimated.

Analysis of correlation between shield TBM construction field data and settlement measurement data (쉴드 TBM 시공데이터와 지반침하 계측데이터 간 상관성 분석)

  • Jung, Ye-Rim;Nam, Kyoung-Min;Kim, Han-Eol;Ha, Sang-Gui;Yun, Ji-Seok;Cho, Jae-Eun;Yoo, Han-Kyu
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.1
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    • pp.79-94
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    • 2022
  • The demand for tunnel construction is increasing as part of underground space development due to urban saturation. The shield TBM method minimizes vibration and noise and minimizes ground deformation that occurs simultaneously with excavation, and shield TBM is generally applied to tunnel construction in urban areas. The importance of urban ground settlement prediction is increasing day by day, and in the case of shield TBM construction, ground deformation is minimized, but ground settlement due to tunnel excavation inevitably occurs. Therefore, in this study, the correlation between shield TBM, which is highly applicable to urban areas, and ground settlement is analyzed to suggest the shield TBM construction factors that have a major effect on ground settlement. Correlation analysis was performed between the shield TBM construction data and ground settlement measurement data collected at the actual site, and the degree of correlation was expressed as a correlation coefficient "r". As a result, the main construction factors of shield TBM affecting ground settlement were thrust force, torque, chamber pressure, backfill pressure and muck discharge. Based on the results of this study, it is expected to contribute to the presentation of judgment criteria for major construction data so that the ground settlement can be predicted and controlled in advance when operating the shield TBM in the future.

A numerical study on the effect of train-induced vibration in shield tunnel (쉴드터널 내부에 작용하는 열차진동 영향에 관한 수치해석적 연구)

  • Kwak, C.W.;Park, I.J.;Park, J.B.
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.2
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    • pp.261-267
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    • 2014
  • Various types of external loads can be applied to the tunnel structure. In a shield tunnel, the vibration from the train may affect the behavior of the adjacent ground. In this study, the railway-induced vibration was estimated and applied to the shield tunnel through 3D numerical simulation. The effective stress analysis based on the finite difference method and Finn model was performed to investigate the potential of liquefaction below the tunnel. Furthermore, pore water pressure and displacement were monitored on a time domain; consequently, the liquefaction potential and dynamic response of the shield tunnel were analyzed. Consequently, it is confirmed that the generation of excess pore water pressure by train-induced vibrating load, however, the amount does not meaningfully affect the potential of liquefaction.

A study on the risk and settlement evaluation of a shield TBM excavated in soft marine sedimentary soils (해저 연약 퇴적층 지반 쉴드 TBM 위험요인 평가 및 장비 침하에 관한 연구)

  • You, Kwang-Ho;Park, Chi-Myeon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.4
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    • pp.355-364
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    • 2016
  • Recently, a 3,250 meter-long tunnel was constructed beneath the sea bed formed of composite sedimentary soils to transport reusable waste heat gas of industrial complex in the west coast of Korea. Some risks such as machine settlement always exist due to the uncertainties of geological and construction factors during the subsea shield TBM tunnelling. In this construction site, the deviation of tunnel alignment caused by shield TBM settlement was occurred during excavation. It was examined that the lack of bearing capacity of soft clay was a main cause. This paper evaluates the risk of shield TBM tunnelling considering the ground conditions. Correlation between machine settlement and its advance rate was evaluated through the analytical equation in which bearing capacity is considered and a 3-D numerical analysis which can simulate the TBM advance condition (in other words, the dynamic condition). It was found out that a shield TBM could settle due to the insufficient bearing capacity of soft clay layers. In order to prevent such the problem, the best advance rate proper to the ground characteristics is needed to be applied. In the ground conditions of the section of interest, it was turned out that if the shield TBM advance rate was maintained between 35 mm/min and 40 mm/min, the machine settlement could be avoided.

A study on EPB shield TBM face pressure prediction using machine learning algorithms (머신러닝 기법을 활용한 토압식 쉴드TBM 막장압 예측에 관한 연구)

  • Kwon, Kibeom;Choi, Hangseok;Oh, Ju-Young;Kim, Dongku
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.2
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    • pp.217-230
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    • 2022
  • The adequate control of TBM face pressure is of vital importance to maintain face stability by preventing face collapse and surface settlement. An EPB shield TBM excavates the ground by applying face pressure with the excavated soil in the pressure chamber. One of the challenges during the EPB shield TBM operation is the control of face pressure due to difficulty in managing the excavated soil. In this study, the face pressure of an EPB shield TBM was predicted using the geological and operational data acquired from a domestic TBM tunnel site. Four machine learning algorithms: KNN (K-Nearest Neighbors), SVM (Support Vector Machine), RF (Random Forest), and XGB (eXtreme Gradient Boosting) were applied to predict the face pressure. The model comparison results showed that the RF model yielded the lowest RMSE (Root Mean Square Error) value of 7.35 kPa. Therefore, the RF model was selected as the optimal machine learning algorithm. In addition, the feature importance of the RF model was analyzed to evaluate appropriately the influence of each feature on the face pressure. The water pressure indicated the highest influence, and the importance of the geological conditions was higher in general than that of the operation features in the considered site.