• Title/Summary/Keyword: shield TBM tunneling

Search Result 40, Processing Time 0.022 seconds

A Study on Key Factors of Ground Settlement Due to Shield TBM Excavation using Numerical Analysis and Field Measurement Comparison (수치해석과 현장 계측값 비교를 통한 Shield TBM 지표침하 영향요소 검토)

  • Jun, Gychan;Kim, Donghyun
    • Journal of the Korean Geosynthetics Society
    • /
    • v.16 no.1
    • /
    • pp.63-72
    • /
    • 2017
  • This study estimates the degree of influence of factors influencing ground surface settlement during tunnel excavation using Shield tunneling trough 3D FE-analyses. Numerical analysis was carried out by considering face pressure, skinplate pressure, excavation length, soil model, element size and soil material properties. Also, Actually constructed shield TBM comparative analysis was conducted by compared with Volume loss model, Pressure model and field measurement data. Skinplate pressure and soil model were the most influential factors, and the analysis results were similar to field measurements when the appropriate skinplate pressure was applied according to the passing stratum.

A study on the establishment of domestic criteria through analysis of shield TBM requirements in overseas ITB (Invitation to Bid) (해외 쉴드TBM 입찰안내서 분석을 통한 국내 발주 기준 정립에 관한 연구)

  • Kim, Ki-Hwan;Kim, Hyouk;Mun, Cheol-Hwa;Kim, Young-Hyu;Kim, Dong-Ho;Lee, Jae-Yong
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.19 no.6
    • /
    • pp.985-997
    • /
    • 2017
  • In many countries, most of the tunneling works have been ordered by the shield TBM, and also Korean companies are actively bidding and execute in this project. In case of Korea, refurbished machines are mainly using in power cable, gas pipelines, and water and sewage tunnel. Also in metro projects, shield TBM of over diameter 7m is required mainly by using brand new machine. Since the shield TBM is not easy to change once it is produced, it is necessary for the client to provide sufficient information on the production conditions so as to satisfy various characteristics of the construction. In this study, to manufacturing optimal shield TBM, the Client's TBM requirements of tunnel construction in Hong Kong and UK was analyzed and compared with the domestic requirements. The results are expected to provide as client's guidelines for bidding stage and manufacturing for shield TBM tunneling in Korea in the future.

Study on the effect of tail void grouting on the short- and long-term surface settlement in the shield TBM Tunneling using numerical analysis (쉴드TBM터널에서 뒤채움 주입이 지반의 단기·장기 침하에 미치는 영향에 대한 수치해석적 연구)

  • Oh, Ju-Young;Park, Hyunku;Kim, Dohyoung;Chang, Seokbue;Lee, Seungbok;Choi, Hangseok
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.19 no.2
    • /
    • pp.265-281
    • /
    • 2017
  • For shallow tunnel constructions, settlement of the ground surface is a main issue. Recent technical developments in shield TBM tunneling technique have enabled a decrease in such settlements based on tunneling with ground deformation controls. For this objective, the tail void grouting is a common practice. Generally surface settlements in a soil of low permeability occur during a tunnel construction but also during a long period after completion of the tunnel. The long-term settlements occur mainly due to consolidation around the tunnel. The consolidation process is caused and determined by the tail void grouting which leads to an excess pore water pressure in the vicinity of the tunnel. Because of this, the grouting pressure has a strong effect on the long-term settlements in the shield tunneling. In order to investigate this effect, a series of coupled hydro-mechanical 3D finite element simulations have been performed. The results show that an increase in grouting pressure reduces the short-term settlements, but in many cases, it doesn't lead to a reduction of the final settlements after the completion of consolidation. Thereby, the existence of a critical grouting pressure is identified, at which the minimal settlements are expected.

Reliability analysis of surface settlement during shield TBM tunneling (쉴드 TBM 터널 굴착시 지표침하에 관한 신뢰성해석)

  • Han, Myeong-Sik;Cho, Kuk-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.18 no.3
    • /
    • pp.305-318
    • /
    • 2016
  • This study is to evaluate the uncertainty of the soil parameters associated with the Gap parameter during shield TBM tunnel excavation of ${\bigcirc}{\bigcirc}$ International Airport Terminal 2 connecting railway construction basic design. And This study is to evaluate the adequacy of the shield TBM design by performing a reliability analysis of the Surface settlement. In addition, By analyzing the reliability indices of the design constants and Sensitivity probability of failure to be used in designing an integer parameter Gap, and By evaluating the design constants of a great influence on the surface subsidence, it was to provide a basis for carrying out an optimum design.

A study on key factors of ground surface settlement due to shield TBM excavation using 3-dimension numerical analysis (3차원 수치해석을 이용한 Shield TBM 굴진시 지표침하 주요 영향요소 분석)

  • Jun, Gy-Chan;Kim, Dong-Hyun
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.17 no.3
    • /
    • pp.305-317
    • /
    • 2015
  • This paper is to perform 3-dimensional numerical analysis considering face pressure, backfill pressure, excavation length, soil model and element size for selecting key factors of ground surface settlement due to shield TBM advancement. According to the numerical analysis results, backfill pressure and soil model are governing factors inducing ground surface settlement. To complement this study, the ground conditions and characteristics of the boring machine will be considered using numerical analysis.

Study on the 3 dimensional numerical analysis method for shield TBM tunnel considering key factors (주요 영향요소를 고려한 쉴드TBM 터널 3차원 수치해석기법 연구)

  • Jun, Gy-chan;Kim, Dong-hyun
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.20 no.2
    • /
    • pp.513-525
    • /
    • 2018
  • A 3 dimensional numerical analysis for shield TBM tunnel should take into account various characteristics of the shield TBM excavation, such as gap, tail void, segment installation, and backfill injection. However, analysis method considering excavation characteristics are generally mixed with various method, resulting in concern of consistency and reliability degradation of the analytical results. In this paper, a parametric study is carried out by using actually measured ground settlement data on various methods that can be used for 3 dimensional numerical analysis of shield TBM tunneling. As a result, we have analyzed and arranged an analytical method to predict similarly the behavior of ground settlement and tunnel face pressure at the design stage. Skin plate pressure, backfill pressure and soil model have been identified as the most significant influences on the ground settlement. The grout pressure model is considered to be applicable when there is no volume loss information on the excavated ground, such as seabed tunnels, or when it is important to identify the behavior around a tunnel, such as surface settlement as well as face pressure. And it is considered that designers can use these guidelines as a base material to perform a reasonable 3 dimensional numerical analysis that reflects the ground conditions and the features of the shield TBM tunneling.

An overview of several techniques employed to overcome squeezing in mechanized tunnels; A case study

  • Eftekhari, Abbas;Aalianvari, Ali
    • Geomechanics and Engineering
    • /
    • v.18 no.2
    • /
    • pp.215-224
    • /
    • 2019
  • Excavation of long tunnels by shielded TBMs is a safe, fast, and efficient method of tunneling that mitigates many risks related to ground conditions. However, long-distance tunneling in great depth through adverse geological conditions brings about limitations in the application of TBMs. Among various harsh geological conditions, squeezing ground as a consequence of tunnel wall and face convergence could lead to cluttered blocking, shield jamming and in some cases failure in the support system. These issues or a combination of them could seriously hinder the performance of TBMs. The technique of excavation has a strong influence on the tunnel response when it is excavated under squeezing conditions. The Golab water conveyance tunnel was excavated by a double-shield TBM. This tunnel passes mainly through metamorphic weak rocks with up to 650 m overburden. These metamorphic rocks (Shales, Slates, Phyllites and Schists) together with some fault zones are incapable of sustaining high tangential stresses. Prediction of the convergence, estimation of the creeping effects and presenting strategies to overcome the squeezing ground are regarded as challenging tasks for the tunneling engineer. In this paper, the squeezing potential of the rock mass is investigated in specific regions by dint of numerical and analytical methods. Subsequently, several operational solutions which were conducted to counteract the challenges are explained in detail.

Determination of effective parameters on surface settlement during shield TBM

  • Kim, Dongku;Pham, Khanh;Park, Sangyeong;Oh, Ju-Young;Choi, Hangseok
    • Geomechanics and Engineering
    • /
    • v.21 no.2
    • /
    • pp.153-164
    • /
    • 2020
  • Tunnel excavation in shallow soft ground conditions of urban areas experiences inevitable surface settlements that threaten the stability of nearby infrastructures. Surface settlements during shield TBM tunneling are related to a number of factors including geotechnical conditions, tunnel geometry and excavation methods. In this paper, a database collected from a construction section of Hong Kong subway was used to analyze the correlation of settlement-inducing factors and surface settlements monitored at different locations of a transverse trough. The Pearson correlation analysis result revealed a correlation between the factors in consideration. Factors such as the face pressure, advance speed, thrust force, cutter torque, twin tunnel distance and ground water level presented a modest correlation with the surface settlement, while no significant trends between the other factors and the surface settlements were observed. It can be concluded that an integrated effect of the settlement-inducing factors should be related to the magnitude of surface settlements.

Development of penetration rate prediction model using shield TBM excavation data (쉴드 TBM 현장 굴진데이터를 이용한 굴착속도 예측모델 개발)

  • La, You-Sung;Kim, Myung-In;Kim, Bumjoo
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.21 no.4
    • /
    • pp.519-534
    • /
    • 2019
  • Mechanized tunneling methods, including shield TBM, have been increasingly used for tunnel construction because of their relatively low vibration and noise levels as well as low risk of rock-falling accidents. In the excavation using the shield TBM, it is important to design penetration rate appropriately. In present study, both subsurface investigation data and shield TBM excavation data, produced for and during ${\bigcirc}{\bigcirc}{\sim}{\bigcirc}{\bigcirc}$ high-speed railway construction, were analyzed and used to compare with shield TBM penetration rates calculated using existing penetrating rate prediction models proposed by several foreign researchers. The correlation between thrust force per disk cutter and uniaxial compressive strength was also examined and, based on the correlation analysis, a simple prediction model for penetration rate was derived. The prediction results using the existing prediction models showed approximately error rates of 50~500%, whereas the results from the simple model proposed from this study showed an error rate of 15% in average. It may be said, therefore, that the proposed model has higher applicability for shield TBM construction in similar ground conditions.

Study on Asymmetric Settlement Trough induced by the 2nd Tunneling of Twin Shield Tunnels in Clay (점토지반 병설쉴드터널에서 후행터널 굴착에 의한 비대칭 침하형상 연구)

  • Ahn, Chang-Yoon;Park, Duhee
    • Journal of the Korean Geotechnical Society
    • /
    • v.37 no.10
    • /
    • pp.55-63
    • /
    • 2021
  • The construction of shield tunnels is being expanded from the small-bore tunnels such as power, telecommunications, water supply, and sewerage pipes to the large bore tunnels such as road and railway tunnels with the advancement of the shield TBM (Tunnel Boring Machine) manufacturing technology. Accordingly, the construction of twin shield tunnels is increasing. Peck (1969) reported that the surface settlement trough is well described by a Gaussian distribution on a single shield tunnel. Hereafter, many studies about the surface settlement trough were performed by the field measurement, laboratory model test, and numerical analysis. This study confirmed that the additional surface settlement trough induced by the 2nd tunneling were well described by using each Gaussian curve for the right and left sides of the settlement trough.