• 제목/요약/키워드: permanent tunnel support

검색결과 18건 처리시간 0.022초

Permanent Shotcrete Tunnel Linings 구축을 위한 고성능 숏크리트 개발 II (II: 용수부에서의 조강시멘트 적용) (Development of High Performance Shotcrete for Permanent Shotcrete Tunnel Linings II(II: Application of high-early strength cement in sump water condition))

  • 박해균;이명섭;김재권;안병제
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2002년도 가을 학술발표회 논문집
    • /
    • pp.695-702
    • /
    • 2002
  • Shotcrete (or Sprayed concrete) has been used as an important support material in New Austrian Tunnelling Method (NATM). Since the mid of 1990, permanent shotcrete tunnel linings such as Single-shell, NMT (Norwegian Method of Tunnelling) has been constructed in many countries for reducing the construction time and lowing construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of permanent shotcrcte linings, high performance shotcrete providing high strength, high durability, better pumpability has to be developed in advance as an integral component. This paper presents the Ideas and first experimental attempts to increase early strength and bond strength of wet-mixed Steel Fiber Reinforced Shotcrete(SFRS) in sump water condition. In order to increase early strength, a new approach using high-early strength cement with liquid alkali-free accelerator has been investigated From the results, wet-mix SFRS with high-early strength cement and alkali-free accelerator exhibited excellent early strength improvement compared to the ordinary portland content and good bond strength even under sump water condition.

  • PDF

Permanent Shotcrete Tunnel Linings 구축을 위한 고성능 숏크리트 개발(III)(시멘트 광물계 분말형 급결제를 사용한 습식숏크리트 현장시험시공) (Development of High Performance Shotcrete for Permanent Shotcrete Tunnel Linings (III) (Field Test of Wet-mixed Shotcrete with Powder Types Cement Mineral Accelerator))

  • 박해균;이명섭;김재권;김용하
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2003년도 봄 학술발표회 논문집
    • /
    • pp.609-617
    • /
    • 2003
  • The use of Shotcrete(Sprayed concrete) for the support of underground excavations was pioneered by the Civil engineering industry. Permanent shotcrete tunnel linings such as Single-shell, NMT(Norwegian Method of Tunnelling) have been constructed in many countries for reducing construction time and lowering construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of Permanent Shotcrete Linings, high performance shotcrete having high strength, high durability, better pumpability has to be developed in advance. This paper presents the ideas and the first field test results of wet-mixed Steel Fiber Reinforced Shotcrete(SFRS) with powder types cement mineral accelerator. From the results, wet-mix SFRS with powdered accelerator exhibited good early strength improvement and less rebound ratio compared to the ordinary accelerator.

  • PDF

터널 지보재로서 H형강 Steel Rib와 삼각지보재의 비교연구 (COMPARISONS BETWEEN H-BEAM STEEL RIB AND LATTICE GIRDERS FOR TUNNEL SUPPORT)

  • 문홍득;박정환
    • 한국지반공학회:학술대회논문집
    • /
    • 한국지반공학회 1995년도 가을 학술발표회 논문집
    • /
    • pp.17.1-24
    • /
    • 1995
  • In tennelling lattice girders have basically the same function as steel arch supports. They serve as elements of temporary lining and in some cases also as part of the permanent lining. Also lattice girders are closely connected with that of the shotcreting lining technique. This paper presents the results of modelling test for analysing shorcrete rebound, shotcreting time and finding void spaces using the aretificial tunnel wall which consist of wood to evaluate the site applicability of lattice girders for tunnel support. Test results indicate that in case of using lattice girders as a tunnel support material, shotcrete rebound, shotcreting time and occurrence of void spaces are relatively reduced comparing to H-beam steel rib. And we can get some informations ths lattice girder has various advantages when we use it as one of tunnel support materials.

  • PDF

터널 영구 지보재로서의 숏크리트 고성능화 및 내구성 평가에 관한 연구 (Performance Improvement and Durability Evaluation of Shotcrete for Permanent Tunnel Support)

  • 이상필;류종현;이상돈;전석원;이정인
    • 터널과지하공간
    • /
    • 제17권4호
    • /
    • pp.266-284
    • /
    • 2007
  • 최근 국내 터널 분야에서는 현장타설 콘크리트 라이닝을 생략한, 이른바 무라이닝 터널을 적용하려는 시도가 수차례 있었으나 숏크리트가 영구 지보재로서의 성능을 확보하고 있는지에 대한 의구심으로 인해 시공으로는 이어지지 못하고 있다. 숏크리트는 시공 상 문제뿐만 아니라 강도기준이 유럽에 비해 현저히 낮고 내구성에서도 많은 문제를 내포하고 있는 것으로 파악되고 있다. 본 연구에서는 효율적인 배합개선을 통하여 압축강도 40 MPa, 휨강도 4.5 MPa 이상의 고강도 숏크리트를 개발하였으며 급결제 종류와 실리카퓸 첨가량을 주 변수로 하여 최대 2년까지의 성능변화 추이를 분석하였다. 또한 단기 내구성 평가를 위해서는 동결융해, 중성화, 염해에 따른 실험실 촉진 실험과 투수시험을 실시하였으며 장기 내구성 검증을 위해서는 실제 운영 중인 고속도로 터널 내에 시편을 적치하여 복합 환경에 대한 영향을 조사하였다. 분석결과 알칼리프리계만이 유일하게 고강도 목표기준을 만족하였으며, 또한 개발된 고성능 숏크리트가 내구성에 있어서도 매우 우수한 것을 확인하였다.

Permanent Shotcrete Tunnel Lining 구축을 위한 고성능 숏크리트 개발( I : 고강도 숏크리트 개발을 위한 새로운 급결제 적용) (Development of High Performance Shotcrete for Permanent Shotcrete Tunnel Lining(I : Application of New Type Accelerator for High Strength Shotcrete))

  • 박해균;이명섭;김재권;안병제
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2002년도 봄 학술발표회 논문집
    • /
    • pp.1023-1030
    • /
    • 2002
  • From the early 1980s, the New Austrian Tunnelling Method (NATM) has been developed as a one of the standard tunneling method in Korea. Approximately 10 years ago, wet-mix shotcrete with sodium silicate accelerator (waterglass) was introduced and widely used to tunnel lining and underground support. However, this accelerator had some disadvantages due to the decrease of long-term strength compared to plain concrete (without accelerator) and low quality of the hardened shotcrete. In order to compensate for these disadvantages, recently developed alkali-free accelerator has been successfully demonstrated in numerous projects and applications as a new material to make tunnels more durable and safer. An experimental investigation was carried out in order to verify the strength behavior of wet-mix Steel Fiber Reinforced Shotcrete (SFRS) with alkali-free accelerator. Compressive strength, flexural strength and equivalent flexural strength were measured by testing specimens extracted from the shotcrete panels. From the results, wet-mix SFRS with alkali-free accelerator exhibited excellent strength improvement compared to the conventional shotcrete accelerator.

  • PDF

Permanent Support for Tunnels using NMT

  • Barton, Nick
    • 한국암반공학회:학술대회논문집
    • /
    • 한국암반공학회 1995년도 정기총회 및 학술발표회
    • /
    • pp.1-26
    • /
    • 1995
  • Key aspects of the Norwegian Method of Tunnelling (NMT) are reviewed. These include a predictive method of support design using the six-parameter Q-system of rock mass characterisation. The rock mass rating or Q-value is updated during tunnel driving. The designed tunnel support generally consists of wet process, steel fibre reinforced shotcrete combined with fully grouted, untensioned rock bolts, Even in poor rock conditions S(fr) + B usually acts as the final rock reinforcement and tunnel lining. Since it is a drained lining, it is very economic compared to cast concrete with membranes. Light, free-standing steel liners are used to prevent water affecting the runnel environment. Rock mass conditions, and hence lining design and cost estimation can be assessed by careful use of seismic surveys. Relationships between the P-wave velocity, the rock mass deformation modulus and the Q-value have recently been established, where tunnel depth, rock porosity and the uniaxial compression strength of the rock are important variables. The rock mass modulus estimate, and simple index testing of the joints, provide the key input which joints are discretely represented (either in two dimensions with the UDEC code or in three dimensions with the 3DEC code) is generally favoured compared to continuum analysis. The latter may give a misleading impression of uniformity and deformations tend to be understimated. Q-system NMT designs of S(fr) + B (fibre reinforced shotcrete and bolting) are numerically checked and adjustments made to bolt capacities and shotcrete thickness if overloading is evident around the modelled profile.

  • PDF

지반 그라우팅에 의한 상부구조물의 안전성 분석 (Stability Analysis of Upper Structures by Soil Grouting)

  • 황철성
    • 한국안전학회지
    • /
    • 제28권4호
    • /
    • pp.58-65
    • /
    • 2013
  • Transportation and further expansion of social infrastructure was needed along the development of urbanization and population concentration. To use the underground space due to the lack of availability of land, it is inevitable to intersect between present structure and tunnel during construction. Soil grouting is one of the ground improvement methods to reinforce weak soil around the underground structures by injection of grouting liquid. Some of central columns of an upper structure are damaged during injection of grouting liquid by injection pressure. To investigate and improve the stability of the tunnel, three dimensional analysis are performed with full construction stages which includes the construction of present underpass, damaging columns of the underpass, reinforcing the columns by H-pile and shear walls, and excavation and construct tunnel. The arrangement of grouting holes such as curtain and horizontal type affects largely to the stability of upper structure and horizontal arrangement diminish the shear forces which is the cause of damage of central columns. The liquid injection type of reinforcement for tunnel is not recommended while the presence of upper structure with columns. Wall type reinforcing is utilize for permant support of upper structures which is affected by grouting injection pressure. H-pile is utilize for temporary support, but not for permanent since the sharing of shear forces is not much to shear wall during tunnel construction.

고성능 숏크리트 라이닝의 설계 및 시공기술 분석 (Recent Issues in the Design and Construction of High-Performance Shotcrete Lining)

  • 배규진;이석원;박해균;이명섭;김재권;장수호
    • 터널과지하공간
    • /
    • 제14권1호
    • /
    • pp.1-15
    • /
    • 2004
  • 숏크리트와 록볼트를 영구 지보재로 사용하는 싱글쉘 터널공법을 도입하고 터널의 장기 내구성을 향상시키기 위해서는 고성능 숏크리트의 개발이 필수적이다. 따라서 본 논문에서는 숏크리트의 고성능화를 위한 최신 숏크리트 혼화재료를 소개하였고, 국외에서 적용되고 있는 숏크리트의 제반 설계기준과 품질관리 시험방법들을 정리하였다. 특히 현장에서 숏크리트의 압축강도를 쉽고 빠르게 추정할 수 있는 공기압식 pin 관입시험의 적용사례를 소개하였다. 또한 숏크리트 라이닝과 지반의 상호작용을 보다 정확하게 평가할 수 있도록 숏크리트 라이닝의 시간 의존적인 경화특성을 고려한 이론적 해석과 숏크리트 라이닝의 설계변수들에 대한 민감도 분석 결과를 고찰하였다. 마지막으로 고성능 숏크리트 라이닝을 영구지보재로 사용하는 대표적인 싱글쉘 터널공법들에 대한 사례들을 제시하였다.

강섬유보강 숏크리트의 휨 성능평가를 위한 보시편과 패널시편의 상관성 연구 (Correlations in the Flexural Performance of SFRC Beams and Panels)

  • 류종현;한승환;김진철;안태송;이상돈
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2002년도 가을 학술발표회 논문집
    • /
    • pp.727-732
    • /
    • 2002
  • Steel Fiber Reinforced Shotcrete(SFRS) has been prevalently used in lining to stabilize tunnel structures as temporary or permanent support. In recent, it is one of the major elements of tunnel construction, and so the quality control of SFRC should be clarified to guarantee the safety. The experimental study has been performed to verify the possible correlations in several chracteristics related to quality of SFRC and examine the applicability of round panel test for in field. The test variables were the type and dosage of accelerator, aspect ratio of fiber, and fiber content. The test results such as compressive strength, flexural strength, flexural toughness, and energy absorption capacity, were exmained and analyzed scrutinizingly.

  • PDF

파이프루프공법이 적용된 터널의 지반거동 유한요소 해석 (Finite Element Analysis on the Ground Behavior for Tunnel with Pipe-roof)

  • 조선아;진규남;심영종
    • 토지주택연구
    • /
    • 제7권4호
    • /
    • pp.261-269
    • /
    • 2016
  • 파이프루프 공법은 개착공법 및 다른 비개착공법에 비해 경제적이고 시공이 비교적 단순한 공법으로 도심지 도로를 횡단하는 신규노선이나 상하수도 등 지하구조물에 적용 사례가 증가하고 있다. 국내외 연구 및 시공사례증가로 공법에 대한 기술적 발전 및 파이프루프의 성능 개선이 이루어지면서 단순 사전보강공법이 아닌 영구 지보재로서 활용가능성이 제기되었다. 따라서 본 연구에서는 파이프루프의 지보효과를 분석하고자 3차원 유한요소 수치해석을 수행하였으며 파이프루프 적용유무와 터널 단면 형상에 따른 지반의 거동을 변위와 응력 변화관점에서 분석하였다. 수치해석 결과 파이프루프를 적용할 경우 터널 상부 지반에서 뚜렷한 변위제어 효과와 함께 터널 단면형상이 지반 및 파이프루프 거동에 상당한 영향을 미치는 것을 확인하였다.