• Title/Summary/Keyword: urban tunnelling

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A manual for the revised TBM tunnel specification (개정 TBM 터널 표준시방서 해설 연구)

  • Sagong, Myung;Jung, Chi Kwang;Moon, Joon Bai;Kim, Jeayoung;Yun, Do Sik;Yu, Myeong Han
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.4
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    • pp.415-428
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    • 2015
  • With increase of the extension of long tunnels and urban tunnelling, demands on the new tunnelling technologies are raised. Currently, drilling and blasting tunnel construction method is mostly used, however, because of sever blast vibration for some occasions, complaints from local residents and rock damages are inevitable. Accordingly, TBM tunnelling is more efficient and effective for such conditions. Nevertheless, tunnel construction costs of TBM cannot compete that of the drill and blasting method in Korea. To overcome such limitations, various TBM equipments and construction technologies are required. In addition, continuous revision of the design standard and specification are required. In this study, a detailed explanation regarding the revised version of TBM section in the tunnel standard specification at 2015 is shown.

Characterization of face stability of shield tunnel excavated in sand-clay mixed ground through transparent soil models

  • YuanHai Li;XiaoJie Tang;Shuo Yang;YanFeng Ding
    • Geomechanics and Engineering
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    • v.33 no.5
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    • pp.439-451
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    • 2023
  • The construction of shield tunnelling in urban sites is facing serious risks from complex and changeable underground conditions. Construction problems in the sand-clay mixed ground have been more reported in recent decades for its poor control of soil loss in tunnel face, ground settlement and supporting pressure. Since the limitations of observation methods, the conventional physical modelling experiments normally simplify the tunnelling to a plane strain situation whose results are not reliable in mixed ground cases which exhibit more complicated responses. We propose a new method for the study of the mixed ground tunnel through which mixed lays are simulated with transparent soil surrogates exhibiting different mechanical properties. An experimental framework for the transparent soil modelling of the mixed ground tunnel was established incorporated with the self-developed digital image correlation system (PhotoInfor). To understand better the response of face stability, ground deformation, settlement and supporting phenomenon to tunnelling excavation in the sand-clay mixed ground, a series of case studies were carried out comparing the results from cases subjected to different buried depths and mixed phenomenon. The results indicate that the deformation mode, settlement and supporting phenomenon vary with the mixed phenomenon and buried depth. Moreover, a stratigraphic effect exists that the ground movement around mixed face reveals a notable difference.

A case study on efficient non pilot 2-Arch Tunnel in the urban (도심지에서 효율적인 무도갱 2-Arch 터널의 설계사례)

  • Yoon, Il-Byung;Kang, Hee-June;Kim, Hong-Dae;Kim, Dong-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.543-552
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    • 2010
  • Due to increase in urban tunnelling as urban population and traffic volume increase, problems related with site security and civil appeal also increase. This paper presents a comparative analysis between conventional 2-arch tunnel method and non-pilot 2 arch tunnel method, which were performed in the basic design of Wie-Rae region. According to the analysis results, non-pilot 2-arch tunnel method is more efficient in terms of stability, constructability, and economic aspect. It is authors' wish that design procedure and method presented in this paper could help the design and construction of non-pilot 2-arch tunnel that should be planned in the near future.

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Technical lessons learnt from the case history of tunnel collapses (터널 붕괴사례로 부터의 기술적 교훈)

  • Shin, Hyu-Soung;Kwon, Young-Cheul;Bae, Gyu-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.835-844
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    • 2009
  • In this study, a database composed by 46 cases of tunnel collapses has been built up. Based on the database, comprehensive data analysis is carried out, providing us a number of the technical lessons, which can be considered in future design and construction to minimize possibility of tunnel collapse disaster. For making a better understanding, the technical lessons are given in two divisions: mountain tunnel and urban tunnel. Tunnel collapses taking place in the former tunnel are generally due to bad discontinuity condition of jointed rock mass. Otherwise, urban tunnel has weak condition generally on ground water and weathering of ground. Most of technical comments given in this paper are made based on the cases of tunnel collapses only used in this study, so that the comments seems to be hard to be available to all the tunnelling cases. However, the comment should be valuable technical lessons for tunnel engineers to consider in tunnel design or construction.

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Damage Detection of Decrepit Tunnel Structures using the NDT (비파괴 검사법에 의한 노후터널의 건전도 평가)

  • Kim, Dong-Gyou;Jung, Ho-Seop
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1388-1391
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    • 2010
  • Recently, the construction of road, subway, railroad, and microtunnel for electricity supplement have been increased because of increasement of traffic in urban area, increasement of industrial transportation, and the network between cities in Korea. The deterioration of tunnel structure may occur by various internal and external factors and particularly, tunnel structures tend to contact with either underground water or harmful ions. Therefore, leakage sometimes occurred through the cracks and joints of concrete lining. The leakage in tunnel may affect the durability of concrete lining. In this study, to evaluate the durability and deterioration of concrete lining in tunnel structures, we were performed the various experiments for compressive strength. Compressive strength obtained from nondestructive inspection and compressive strength test varies according to the concrete lining conditions.

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Damage Assessment of Buried Pipelines Due to Tunnelling (터널 굴착에 의한 지중 매설관의 손상평가)

  • 유충식;윤효석
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.471-478
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    • 2000
  • Ground movements are inevitably caused by tunnel construction in soft ground. In the design and construction of tunnels in urban areas, the potential effects of buried pipelines by ground movements are one of the important design cosiderations. Generally, the most common modes of failure of buried pipelines due to ground movements are tensile fracture of main pipelines, rotation angle and pull-out displacement at joints. In the parametric study, a wide range of conditions were considered, including tunnel diameter(D), tunnel depth(Z$\sub$0/), volume loss(V$\sub$ι/) and inflection point(i). Based on this results, design charts, which are applicable to assess potential damage of buried pipelines associated ground movements due to tunnelling, are developed.

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Influence Zones subjected to Pile-Soil-Tunnelling Interaction (파일-흙-터널의 상호거동에 따른 영향권)

  • Lee, Yong-Joo;Bassett, R. H.
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1351-1360
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    • 2005
  • New construction for public transport in congested urban areas will involve tunnel construction adjacent to existing building or bridge foundations and services due to the lack of surface space. Therefore, careful assessment of the important underground structure-soil-tunnelling interaction is relatively new, currently only limited information is available. In this study, the authors carried out FE analysis and the laboratory model test using the photogrammetric technique and suggested the influence zones associated with the normalised pile tip settlement during new tunnel construction.

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The Application of Nonlinear 3-D Tunnel Analysis Program for the Improved Efects of Steel Pipe Reinforced Multi Step Grouting Method (3차원 터널해석에 의한 강관 다단 그라우팅의 보강효과)

  • Kim, Hyeong-Tak;Lee, Bong-Yul;Kim, Hak-Moon
    • Proceedings of the Korean Geotechical Society Conference
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    • 1995.10a
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    • pp.25.2-38
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    • 1995
  • the Effect of steel pipe reinforced multi-step grouting(SPRG) technique to inrove the ground far ahead of the excavation face was investigated by means of numerical analysis. It was found taht the nonlinear 3-D FEM program performed well to evaluate the usefulness of the SPRG technique in soft ground tunnelling, and about 20% of settlement control in this particular case possible. Therefore in urban subway tunnel construction, the New Austirial Tunnelling Method can be satisfactorily applied even in poor ground conditon with aid of the SPRG technique.

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Determination of priorities for management to reduce collapse accident of open excavation and road sink in urban areas (도심지 개착식 굴착공사 붕괴사고 및 도로함몰 저감을 위한 우선 관리 요소 결정)

  • Seong, Joo-Hyun;Jung, Min-Hyung
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.3
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    • pp.489-501
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    • 2017
  • The collapse accidents during a open ground excavation in urban areas not only lead to human injuries and material damages in the construction site, but also lead to road sinks and damages to the adjacent facilities due to settlement of ground around the construction site. Therefore, during a open ground excavation in the urban areas, it is necessary to thoroughly prepare for prevention of collapse accidents, and consider whole construction stage such as planning, design and construction. In this study, the priorities to be managed mainly were obtained in order to prevent collapse accidents during a open ground excavation. After analyzing results from past accidents cases for open ground excavations, priorities were evaluated regarding collapse-inducing elements using the Delphi technique which is a decision-making method by consensus among experts. As a result, insufficient groundwater treatment, bad geotechnical investigation and instability on construction, etc. were obtained as priorities for prevention of collapse accidents.

A study on the feasibility assessment model of urban utility tunnel by analytic hierarchy process (계층의사분석 기법을 적용한 도심지 공동구 타당성 평가모델 연구)

  • Chung, Jee-Seung;Na, Gwi-Tae
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.1
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    • pp.131-144
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    • 2018
  • The urban center of a large city has a high concentration ratio of population, commerce, and traffic. Therefore, the expected effect is high from the introduction of the urban utility tunnel and it also has sufficient economic feasibility considering life cycle cost. Moreover, the construction cost can be greatly reduced if it is included in a large underground development such as a subway or a complex transfer center construction. However, it is not reflected in actual underground development plan. When planning a urban utility tunnel in Korea, it is expected to have difficulties such as the cost of relocation of the existing Life-Line, conflicts among the individual facility institutions, procurement of construction resources and sharing. Furthermore, it is possible to promote the project only if a consensus is drawn up by a collective council composed of all facilities and project developers. Therefore, an optimal alternative should be proposed using economic analysis and feasibility assessment system. In this study, the analytic hierarchy process (AHP) is performed considering the characteristics of urban areas and the importance of each indicator is quantified. As a result, we can support reasonable design capacity optimization using the feasibility assessment system.