• Title/Summary/Keyword: TBM Tunnel

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Analysis on Downtime element of Gripper TBM based on field data (현장 데이터 분석을 통한 Gripper TBM의 Downtime 요소 분석)

  • Park, Jinsoo;Song, Ki-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.23 no.6
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    • pp.393-402
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    • 2021
  • The first TBM introduced in Korea was the gripper TBM, which was applied to the Gudeok Waterway Tunnel in 1985. In the initial stage of the introduction of the gripper TBM, many applications were mainly focused on waterway tunnels (Tunnel Mechanized Construction Design, 2008). Currently, the construction range of gripper TBM in Korea is widely applied to not only waterway tunnels, but also subways, railway tunnels, and TBM+NATM expansion. Overseas, gripper TBM is generally applied, and even when NATM tunnel is applied, it is applied as an exploration tunnel because of the excellent advance rate of gripper TBM and used as an evacuation tunnel after completion. Due to the fast excavation speed, the application of the gripper TBM in the rock section of weathered rock or higher can minimize the environmental and civil complaints caused by creating a large number of work areas when planning long tunnels or mountain tunnels. In this study, the work process of the general gripper TBM was analyzed by analyzing the construction cycle and the gripper TBM with a diameter of 2.6~5.0 m, which was applied the most in Korea. Downtime was investigated and analyzed.

Predicting ground condition ahead of tunnel face utilizing electrical resistivity applicable to shield TBM (Shield TBM에 적용 가능한 전기비저항 기반 터널 굴착면 전방 예측기술)

  • Park, Jin-Ho;Lee, Kang-Hyun;Shin, Young-Jin;Kim, Jae-Young;Lee, In-Mo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.6
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    • pp.599-614
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    • 2014
  • When tunnelling with TBM (Tunnel Boring Machine), accessibility to tunnel face is very limited because tunnel face is mostly occupied by a bunch of machines. Existing techniques that can predict ground condition ahead of TBM tunnel are extremely limited. In this study, the TBM Resistivity Prediction (TRP) system has been developed for predicting anomalous zone ahead of tunnel face utilizing electrical resistivity. The applicability and prediction accuracy of the developed system has been verified by performing field tests at subway tunnel construction site in which an EPB (Earth Pressure Balanced) shield TBM was used for tunnelling work. The TRP system is able to predicts the location, thickness and electrical properties of anomalous zone by performing inverse analysis using measured resistivity of the ground. To make field tests possible, an apparatus was devised to attach electrode to tunnel face through the chamber. The electrode can be advanced from the chamber to the tunnel face to fully touch the ground in front of the tunnel face. In the 1st field test, none of the anomalous zone was predicted, because the rock around the tunnel face has the same resistivity and permittivity with the rock ahead of tunnel face. In the 2nd field test, 5 m thick anomalous zone was predicted with lower permittivity than that of the rock around the tunnel face. The test results match well with the ground condition predicted, respectively, from geophysical exploration, or directly obtained either from drilling boreholes or from daily observed muck condition.

The First Case Study of TBM Pre-Excavation Type 2-Arch Tunnel in Korea (국내 최초 TBM선굴진 2-Arch터널 설계사례 연구)

  • Hyung-Ryul Kim;Sang-Jun Jung;Jun-Ho Kang
    • Tunnel and Underground Space
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    • v.33 no.4
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    • pp.255-264
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    • 2023
  • As the demand for urban underground space increases recently, urban tunnel planning is actively progressing. In the urban area, a underground station is planned in consideration of the living environment of residents, and 2-arch tunnel is applied for the stability of existing structures and reduction of environmental damage. However, since the depth of weak rock mass is deeply distributed in the urban area due to severe weathering, careful planning is required to secure tunnel stability. In addition, if TBM mechanical excavation is applied as the main tunnel excavation method considering the composite ground in urban area, the construction connectivity with the 2-arch tunnel of the NATM concept may be deteriorated. In this study, the design case of applying TBM pre-excavation type 2-arch tunnel for the first time in Korea was mainly described. The main considerations for the segment design of TBM pre-excavation type 2-arch tunnel were explained for side tunnels. Also, a stability analysis was conducted to verify the effectiveness and adequacy of the TBM pre-excavation type 2-arch tunnel.

Modern High-Power TBM with Advanced Procurement System (오늘날의 고성능 TBM과 선진 장비조달 방안)

  • Jee, Warren W.
    • Tunnel and Underground Space
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    • v.23 no.3
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    • pp.161-168
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    • 2013
  • Recently, the application of High-Power mechanized tunnelling technology has been expended around the world. Especially, High-power Modern TBM machines are used in a successful results. Essential for the great success of this modern TBM in difficult rock conditions are based on the development of machine power, suitable better cutter developments, and also developed assesment technology regards on the extensive site investigations. OPP (Owner Procurement Process) system is a proven alternative contract delivery method that is potentially applicable to many tunnel projects. Using the OPP, the owner specifies and procures the TBMs and tunnel lining in advance of the tunnel contract procurement and provides TBM to a tunnel contractor with a goals of reducing project risks and accelerating project schedule. Depending on the blasting vibrations and noises, mechanized tunnelling will be more important particularly in city areas.

Study on Risk Priority for TBM Tunnel Collapse based on Bayes Theorem through Case Study (사례분석을 통한 베이즈 정리 기반 TBM 터널 붕괴 리스크 우선순위 도출 연구)

  • Kwon, Kibeom;Kang, Minkyu;Hwang, Byeonghyun;Choi, Hangseok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.6
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    • pp.785-791
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    • 2023
  • Risk management is essential for preventing accidents arising from uncertainties in TBM tunnel projects, especially concerning managing the risk of TBM tunnel collapse, which can cause extensive damage from the tunnel face to the ground surface. In addition, prioritizing risks is necessary to allocate resources efficiently within time and cost constraints. Therefore, this study aimed to establish a TBM risk database through case studies of TBM accidents and determine a risk priority for TBM tunnel collapse using the Bayes theorem. The database consisted of 87 cases, dealing with three accidents and five geological sources. Applying the Bayes theorem to the database, it was found that fault zones and weak ground significantly increased the probability of tunnel collapse, while the other sources showed low correlations with collapse. Therefore, the risk priority for TBM tunnel collapse, considering geological sources, is as follows: 1) Fault zone, 2) Weak ground, 3) Mixed ground, 4) High in-situ stress, and 5) Expansive ground. In practice, the derived risk priority can serve as a valuable reference for risk management, enhancing the safety and efficiency of TBM construction. It provides guidance for developing appropriate countermeasure plans and allocating resources effectively to mitigate the risk of TBM tunnel collapse.

A study on the selection of optimal cross section according to the ventilation system in TBM road tunnels (TBM 도로터널의 환기방식에 따른 최적단면 선정에 관한 연구)

  • Lee, Ho-Keun;Kang, Hyun-Wook;Kim, Hyun-Soo;Kim, Hong-Moon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.2
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    • pp.135-148
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    • 2013
  • Recently, road tunnels have become longer and the plans for long and deep road tunnel have been underway in urban areas. These long and deep tunnel excavations include NATM and TBM. Shield TBM is applied to around 80% of traffic tunnels in Europe, and approximately 30% of them in other developed countries. However, as much of equipment is imported from foreign countries at high prices and distribution rate of TBM tunnel is considerably low in Korea, NATM excavation method is commonly used. To increase TBM tunnel, it is necessary to do assure economic feasibility with the supply-demand of TBM equipment. For this, the selection of standardized TBM diameter is urgently needed. Therefore, the study aims to estimate the standardized optimum section properties of TBM by examining TBM excavation cross section utilization depending on the volume of traffic, the number of lane and its cross-section type(single or double deck), and ventilation system.

Case of assembly process review and improvement for mega-diameter slurry shield TBM through the launching area (발진부지를 이용한 초대구경 이수식 쉴드TBM 조립공정 검토 및 개선 사례)

  • Park, Jinsoo;Jun, Samsu
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.6
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    • pp.637-658
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    • 2022
  • TBM tunnel is simple with the iterative process of excavating the ground, building a segment ring-build, and backfilling. Drill & Blast, a conventional tunnel construction method, is more complicated than the TBM tunnel and has some restrictions because it repeats the inspection, drilling, charging, blasting, ventilation, muck treatment, and installation of support materials. However, the preparation work for excavation requires time and cost based on a very detailed plan compared to Drill & Blasting, which reinforces the ground and forms a tunnel after the formation of tunnel portal. This is because the TBM equipment for excavating the target ground determines the success or failure of the construction. If the TBM, an expensive order-made equipment, is incorrectly configured at the assembly stage, it becomes difficult to excavate from the initial stage as well as the main excavation stage. When the assembled shield TBM equipment is dismantled again, and a situation of re-assembly occurs, it is difficult throughout the construction period due to economic loss as well as time. Therefore, in this study, the layout and plan of the site and the assembly process for each major part of the TBM equipment were reviewed for the assembly of slurry shield TBM to construct the largest diameter road tunnel in domestic passing through the Han River and minimized interference with other processes and the efficiency of cutter head assembly and transport were analyzed and improved to suit the site conditions.

Characteristics of defect on segmental lining of TBM tunnel in operational subway (운용중인 국내 지하철 TBM터널의 세그먼트라이닝 결함특성 분석)

  • Choo, Jinho;Lee, DongHun;Noh, EunChul
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.1
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    • pp.109-128
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    • 2022
  • The precise inspection for safety and diagnosis (PISD) of tunnel has been conducted by the special act on safety control of public structures. However, the present assessment for the segmental lining of TBM tunnel has limitation such as: NDTs for integrity, segmental configuration for field inspection, and consideration for jacking system. Even if the number of TBM tunnel is less than 1% of enrolled facility in FMS, more attention to maintenance should be necessary due to its usage such as multi-use facility and national important facility. Compared to NATM tunnel, excavated by drilling and blasting and then installed lining by cast-in-place within 6~12 m, TBM tunnel is cut out ground by disk and cutter-bit and then assembled 7 pieces of precast segment, 1.2~1.4 m wide. Different features of design, construction, and maintenance should be considered to be more exact evaluation of TBM tunnel. The characteristics of defect is categorized and analyzed with 11 operational TBM tunnels in domestic subway. To be more comprehend various particular defects, foreign studies have been also adapted. Crack and leakage are categorized in 7 patterns. Breakage/spalling and corrosion are also grouped into 3 patterns. Patterned defects or damages are fed back in design, construction, and are useful guidelines for maintenance stage in future.

Application technique on thrust jacking pressure of shield TBM in the sharp curved tunnel alignment by model tests (축소모형실험을 통한 급곡선 터널에서의 Shield TBM 추진 압력 적용 기술에 대한 연구)

  • Kang, Si-on;Kim, Hyeob;Kim, Yong-Min;Kim, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.2
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    • pp.335-353
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    • 2017
  • This paper presents the application technique on thrust jacking pressuring of shield TBM in the sharp curved tunnel alignment by model tests. Recently, the application of shield TBM method as mechanized tunnelling is increasing to prevent the vibration and noise problems, which can be occurred in the NATM in the urban area in Korea. However, it is necessary to plan the sharp curved tunnel alignment in order to avoid the building foundation and underground structures, to develop the shield TBM operation technique in the shape curved tunnel alignment. Therefore, the main operation parameters of shield TBM in the curved tunnel alignment are reviewed and analyzed based on the case study and analytical study. The results show that the operation of shield jacking force system is the most important technique in the shape curved tunnel alignment. The simplified scaled model tests are also carried out in order to examine the ground-shield TBM head behaviour. The earth pressures acting on the head of shield TBM are investigated according to two different shield jacking force systems (uniform and un-uniform pressure) and several articulation angles. The results obtained from the model tests are analysed. These results will be very useful to understand the shield TBM head interaction behaviour due to the shield jacking operation technique in the shape curved tunnel alignment, and to develop the operation technique.

A Database to Estimate TBM Manufacturing Specifications and Its Statistical Analysis (TBM 제작 사양을 추정하기 위한 데이터베이스의 구축과 통계분석)

  • Chang, Soo-Ho;Park, Byungkwan;Lee, Chulho;Kang, Tae-Ho;Bae, Gyu-Jin;Choi, Soon-Wook
    • Tunnel and Underground Space
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    • v.27 no.5
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    • pp.271-281
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    • 2017
  • Generally, TBM specifications have been empirically designed by the know-hows of its manufacturers. Since they govern the excavation performance and the cost of TBMs, it is very crucial to reliably determine them in the design stage of TBMs. In this study, a database consisting of TBM data collected from a various kinds of TBM tunnel projects was built to propose the statistical correlations for estimating TBM main specifications. From the statistical analyses, TBM outer diameters are found to have a strong effect on the TBM specifications such as thrust, torque and cutterhead driving power, which are much more important than TBM types and ground conditions.