• Title, Summary, Keyword: Shield TBM tunnel

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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.

Analysis on the behavior of shield TBM cable tunnel: The effect of the distance of backfill grout injection from the end of skin plate (뒷채움 주입 거리에 따른 전력구 쉴드 TBM 터널의 거동 특성 분석)

  • Cho, Won-Sub;Song, Ki-Il;Ryu, Hee-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.2
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    • pp.213-224
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    • 2014
  • Recently, tunnelling with TBM is getting popular for the construction of cable tunnel in urban area. Mechanized tunnelling method using shield TBM has various advantages such as minimization of ground settlement and prevention of vibration induced by blasting that should be accompanied by conventional tunnelling. In Korea, earth pressure balance (EPB) type shield TBM has been mainly used. Despite the popularity of EPB shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Especially, the effect of backfill grout injection on the behavior of cable tunnel driven by shield TBM is investigated in this study. Tunnelling with shield TBM is simulated using 3D FEM. The distance of backfill grout injection from the end of shield skin varies. Sectional forces such as axial force, shear force and bending moment are monitored. Vertical displacement at the ground surface is measured. Futhermore, the relation between volume loss and the distance of backfill grout injection from the end of skin plate is derived. Based on the stability analysis with the results obtained from the numerical analysis, the most appropriate injection distance can be obtained.

A Study on ground behavior of shield TBM lunching area during xcavation (Shield TBM 발진부 굴착에 따른 지반거동에 관한 연구)

  • O, Tae-Sang;Kim, Bae-Sik;Sin, Han-Cheol;Kim, Sang-Hwan
    • Proceedings of the KSR Conference
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    • pp.353-364
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    • 2011
  • This paper presents the ground behaviour of shield TBM lunching area during excavation. In order to perform this study, a scaled model test was carried out in the 1/45 scale for a field tunnel in practice where the tunnel had about 7.8 m diameter at Seoul Metro Line 9 construction site. The test to simulate earth pressure balance (EPB) shield TBM tunnelling at the lunching area was conducted with the developed small scaled shield TBM machine. Measurements were performed during simulation of excavation for total jacking thrust force, ground displacements and pressures. Based on the analysis of simulation results, the stability of ground was verified and evaluated. In particular, the suitable reinforcement range and methods are also suggested. In addition, these results are useful for engineers and technicians to select suitable and serviceable machine operation parameters and reduce environmental influence at all stages of tunnel construction.

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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.

Construction Plan by Large Diameter Shield TBM Method and Analysis of Deformation on Site Under Soo-Young River (대구경 Shield TBM공법에 의한 수영강 하저터널 시공계획 및 시공중 발생되는 거동의 공학적 분석)

  • 윤현돈;황규호;최기훈
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.25-32
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    • 2001
  • Doosan Construction & Engineering Co., Ltd is building a railway tunnel beneath the Soo-Young River connecting MinLak Station and Centum City Station, a section 230, subway line 2, Pusan City, Korea. When completed the tunnel will have a finished inner diameter of 6.5m(21.311) throughout its total length of 840m(420m = 0.52 miles, Two Single Track Tunnel : 420m+420m). The ground profile of the face toward shield machine is composed of multi layers, silty clay, clayey gravel, soft rock etc. This research paper is to predict ground deformation and variation of stresses around tunnel using Hyperbolic model, and to reflect the works on the next shield tunneling project. And this research paper is analyzed data of measuring instrument (such as settlement gauge, inclinometer, Multiple extensometer, etc.) which is installed along tunnel line for safety of tunnel. For calculations, the finite difference Method is applied. Backfill grouting material is supposed to have instantly strength of 10kg/$\textrm{cm}^2$ above, although its strength is available after 24 hours passed.

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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.

Improvement Plan of Excavation Performance Based on Shield TBM Performance Prediction Models and Field Data (쉴드 TBM 성능예측모델과 굴진자료 분석을 통한 굴진성능 개선방안)

  • Jung, Hyuksang;Kang, Hyoungnam;Choi, Jungmyung;Chun, Byungsik
    • Journal of the Korean Geoenvironmental Society
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    • v.11 no.2
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    • pp.43-52
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    • 2010
  • Shield method is the tunnel boring method that propels a steel cylinder in the ground and excavates tunnels at once. After Marc Isambard Brunel started using the method for the Thames Riverbed Tunnel excavation in London, many kinds of TBM (Tunnel Boring Machine) developed and applied for the construction of road, railway, electricity channel, pipeline, etc. In comparison with NATM concept that allows to observe ground condition and copes with difficulty. The machine selected before starting construction is not able to be changed during construction in shield TBM. Therefore the machine should be designed based on the ground survey result and experiment, so that the tunnel might be excavated effectively by controlling penetration speed, excavation depth and cutter head speed according to the ground condition change. This research was conducted to estimate penetration depth, excavate speed, wear of disc cutter on Boondang Railway of the Han Riverbed Tunnel ground condition by TBM performance prediction models such as NTNU, $Q_{TBM}$, Total Hardness, KICT-SNU and compare the estimated value with the field data. The estimation method is also used to analyze the reason of poor excavation efficiency at south bound tunnel.

Study on the structure of the articulation jack and skin plate of the sharp curve section shield TBM in numerical analysis (수치해석을 통한 급곡선 구간 Shield TBM의 중절잭 및 스킨플레이트 구조에 관한 연구)

  • Kang, Sin-Hyun;Kim, Dong-Ho;Kim, Hun-Tae;Song, Seung-Woo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.3
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    • pp.421-435
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    • 2017
  • Recently, due to the saturation of ground structures and the overpopulation of pipeline facilities requires to development of underground structures as an alternative to ground structures. Thus, mechanized tunnel construction of the shield TBM method has been increasing in order to prevent vibration and noise problems in construction of the NATM tunnel for the urban infrastructure construction. Tunnel construction plan for the tunnel line should be formed in a sharp curve to avoid building foundation and underground structures and it is inevitable to develop a shield TBM technology that suits the sharp curve tunnel construction. Therefore, this study is about the structural stability technology of the articulation jack, shield jack and skin plate for the shield TBM thrust in case of the mechanized tunnel construction that is a straight and sharp curve line. The construction case study and shield TBM operation principle are examined and analyzed by the theoretical approach. The torque of the cutter head, the thrust of the articulation jack and the shield jack, the amount of over cutting for curve is important respectively in shield TBM construction of straight and sharp curve line. In addition, it is very important to secure the stability of the skin plate structure to ensure the safety of the inside worker. This study examines the general structure and construction of the equipment, experimental simulation was carried out through numerical analysis to examine the main factors and structural stability of the skin plate structure. The structural stability of the skin plate was evaluated and optimizes the shape by comparing the loads of the articulation jack by selecting the virtual soil to be applied in a straight and sharp curve line construction. Since the present structure and operation method of the shield TBM type in domestic constructions are very similar, this study will help to develop the localized shield TBM technology for the new equipment and the vulnerability and stability review.

Disc Cutter Consumptions Prediction on Applying Shield TBM at the Han Riverbed Tunnel (한강하저터널의 쉴드TBM 적용시 디스크 커터 소모량 예측과 소모량)

  • Choi, Jung-Myung;Jung, Hyuk-Sang;Chun, Byung-Sik;Lee, Yong-Joo
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.562-570
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    • 2010
  • This study was conducted to estimate the number of disc cutter consumption and to predict amount of disc cutters when a shield TBM(Tunnel Boring Machine) of the Han Riverbed Tunnel was applied. In fact, it is almost impossible to change the machine after starting the excavation using the shield TBM method. Therefore, it is important to design an appropriate equipment in the shield method - an efficiency choice of the operation equipment plays a key role in the shield tunnel processing. For the above reason, the disc cutter consumption prediction is quite important so that the detailed analysis is required. A number of disc cutter consumption was predicted by the three methods, viz. KOMATSU, MITSUBISHI and NTNU. In addition, the predicted results were compared with field data. The prediction of disc cutter consumption showed that 237 for KOMATSU, 501 for MITSUBISHI, and 634 for NTNU, respectively. However, a total number of 1,263 disc cutter consumption were investigated during the tunnel construction. It was found that there was a huge difference between the predicted and real values of the disc cutter consumption. The more detailed investigation showed that the disc cutter was worn out bluntly in the northbound tunnel, meanwhile it was worn out sharply in the southbound tunnel. In particular, the disc cutter consumption in the southbound tunnel was increased rapidly because of rear abrasion for remaining mucks in the chamber.

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An Experimental Study on Shield TBM Tunnel Face Stability in Soft Ground (연약지반에서의 쉴드 TBM 굴착시 막장면 안정성 평가를 위한 실험적 연구)

  • Kim, Yong-Man;Lee, Sang-Duk;Choo, Seok-Yeon;Koh, Sung-Yil
    • Journal of the Korean Society for Railway
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    • v.16 no.1
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    • pp.47-51
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    • 2013
  • In this study, we carried out an experimental shield TBM excavation model test using a down-scale device in soft clay, to understand tunnel-face stability properties in relation to changes in slurry pressure. We performed five tests according to tunnel depth (0.5D, 0.75D, 1.0D, 1.25D, 1.5D), and compared theoretical tunnel-face pressure with model test results. The range in theoretical tunnel-face slurry pressure ($P_{min}{\leq}P_{slurry\;pressure}{\leq}P_{max}$), which is determined by earth pressure and water level, was very similar to the model test result. This result was due to the more isotropic condition of the soft clay ground, than of rocky ground.