• Magazine of korean Tunnelling and Underground Space Association
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• v.22 no.1
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• pp.26-35
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• 2020

Tunnelling to bypass major landslide areas is considered as a good and long-term environmentally friendly solution to reduce an existing hazard. In Norway, hundreds of kilometres of tunnels have been constructed in areas prone to landslides and snow avalanches. Although tunnelling is considered as an expensive mitigation strategy for bypassing landslides, analysis indicate that in some cases the cost of building a tunnel can be repaid by savings in driving costs (fuel) alone over a period of 5-10 years due to reduced driving distances. The other benefits of constructing tunnels in landslide areas include savings in time and increased safety. The Norwegian Method of Tunnelling (NMT) is considered safe, efficient and cost effective compared to other tunnelling techniques. Some aspects of NMT, which are considered safe and cost efficient, are presented. The application of updated rock support techniques, including reinforced ribs of shotctrete (RRS), which is a key component of the Norwegian Method of Tunnelling (NMT), is highlighted.

• Tunnel and Underground Space
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• v.2 no.1
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• pp.123-151
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• 1992

“Norwegian Tunnelling in General" will cover the following subjects : - Short introduction to the geology of Norway - Major considerations in rock installations - Hydropower plants, roads, tunnels, oil and gas storage in rock, drinking water storage, sewage plants, frozen food storage, defence and civil defence projects, including sports arenas and swimming pools, etc.

• Tunnel and Underground Space
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• v.15 no.1 s.54
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• pp.22-27
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• 2005

This paper presents an article explaining a TBM project overall in Norway. The paper which published in Norwegian TBM Tunnelling by Norwegian Soil and Rock Eng. Assoc. in 1998, contains most of the items considered in TBM tunnelling. New powerplants, tunnels and dams have been built at Meraker in Central Norway. A total of 44 km of tunnels with cross sections varying from $7\;m^2\;to\;32\;m^2$ have been excavated in hard rock formation. Tunnel of 10 km with the 3.5 m diameter was excavated by a HP TBM in a year. his project gives the special attention to the TBM drive and equipment selection, including planning, site organization and performance.

• Tunnel and Underground Space
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• v.17 no.3 s.68
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• pp.225-233
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• 2007

Because of Norwegian topography as valleys and fjords, a large number of tunnels has been built and 59 of them have been excavated by TBM for last 30 years. Prognosis technology has been developed and improved through lots of TBM experiences, and the NTNU prediction model has been completed. This paper focuses the improvement of net penetration rate and advance rate in 14 Norwegian and 4 Koran TBM tunnelling sites of which data were reported. Through this period, net penetration rate as well as advance rate were increased to double with the improvement of disc cutter size and cutter arrangement in Norway. These rates in Korea were also increased for 15 years even though the rates were lower compared to Norwegian. It is estimated that these low rates were mainly caused by using disc cutters less than 17 inch diameter. It is expected that net penetration rate and advance rate can be increased by improvement of machine and tunnelling technology, especially by using 17 or 19 inch of the disc cutter size in the Korean full face mechanical tunnelling site.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.5
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• pp.563-573
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• 2015

For hard rock subsea tunnels the most challenging rock mass conditions are in most cases represented by major faults/weakness zones. Poor stability weakness zones with large water inflow can be particularly problematic. At the pre-construction investigation stage, geological and engineering geological mapping, refraction seismic investigation and core drilling are the most important methods for identifying potentially adverse rock mass conditions. During excavation, continuous engineering geological mapping and probe drilling ahead of the face are carried out, and for the most recent Norwegian subsea tunnel projects, MWD (Measurement While Drilling) has also been used. During excavation, grouting ahead of the tunnel face is carried out whenever required according to the results from probe drilling. Sealing of water inflow by pre-grouting is particularly important before tunnelling into a section of poor rock mass quality. When excavating through weakness zones, a special methodology is normally applied, including spiling bolts, short blast round lengths and installation of reinforced sprayed concrete arches close to the face. The basic aspects of investigation, support and tunnelling for major weakness zones are discussed in this paper and illustrated by cases representing two very challenging projects which were recently completed (Atlantic Ocean tunnel and T-connection), one which is under construction (Ryfast) and one which is planned to be built in the near future (Rogfast).

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1994.03a
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• pp.1-11
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• 1994

현재 국내 터널의 설계와 시공은 대부분 NATM의 원리를 적용하고 있다. 그러나 터널의 설계 접근방법과 시공의 상황을 살펴보면 NATM을 국내 지질에 적용하는 것이 항상 최적이 아니라는 것을 알수 있으며, 국내 터널의 시공에 있어서도 NATM과 다른 개념의 도입과 정확한 이해가 필요하다는 것을 많은 기술자가 느끼고 있다. 따라서 보다 경제적이고 안전한 터널 시공방법의 결정을 위해 NATM의 개념과 다른 터널 설계 및 시공방법으로 노르웨이 터널 시공법(Norwegian Method of Tunnelling, NMT)을 소개하고자 한다. (중략)

• Tunnel and Underground Space
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• v.4 no.1
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• pp.47-54
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• 1994

NATM has been applied most of tunnel design and construction in Korea these days. But, if you observe the tunnel designing method and construction conditions, you can see that the NATM isn's usually the most suitable to Korean geology. Also most of engineers feel that it is necessary to understand the NATM correctly adn to introduce another tunnelling principle which can be applied more economically and safely. So, we'd like to introduce a new tunnelling concept. Norwegian Method of Tunnelling(NMT) by comparing the NATM. The main character of NMT is that the forward prediction of conditions and the support of tunnel is done through geological investigation in details. And it can be compared with NATM, in which the support pattern is decided by monitoring of tunnel deformation on the construction.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.695-702
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• 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.

• Magazine of korean Tunnelling and Underground Space Association
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• v.22 no.1
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• pp.36-44
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• 2020

E39 프로젝트 그룹은 초기 세미나 및 타당성 검토 결과는 통하여 송내 피오르드 크로싱을 위해 제안된 몇 가지 대안들에 대해서 기술적으로 긍정적인 평가를 내리고 있다. 향후 개발 단계에서 이를 검증하기 위한 설계 및 검증 과정이 필요하다. 프로젝트 그룹은 세 가지 주요 대안에 집중하고 있다. 가장 가능성 있는 컨셉은 사장교 형식의 부유식 교량이며, 일반교 형식의 부유식 교량도 대안이 될 수 있다. 또한 부유식 터널구조는 아직 적용된 사례가 없으나 검증을 위한 많은 연구들이 진행되고 있다. 이렇게 송내 피오르트 크로싱에 대한 대안은 아래 표 4와 같이 크게 3가지 컨셉으로 정리 할 수 있으며 향후 해결해야 할 많은 기술적인 과제들을 앉고 있다.

• Magazine of korean Tunnelling and Underground Space Association
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• v.21 no.2
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• pp.103-116
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• 2019

Permanent sprayed concrete tunnel linings waterproofed with bonded membranes have been used at a number of important traffic projects over the last decade. Research has been carried out in several teams in order to increase the understanding of the function, properties and behavior of such linings under different loading and boundary conditions. The basic layout of this lining gives fundamental different system properties compared to the traditional lining systems. The main differences pertain to the groundwater exposure and the resulting hydraulic loading, the response of the concrete and membrane materials to this loading, as well as the geomechanically induced loading of the lining structure. The current understanding of the function and properties of such lining structures is presented in the paper based on review of recent research carried out in Norway, as well as field observations and monitoring carried over a several years. The influence of the water exposure on the final condition of the concrete and membrane materials has proven to be of vital importance for proper material testing and acceptance, assessments of the mechanical contribution of the bonded membrane, as well as assessments of the longterm durability of such linings. Obtaining realistic material parameters for the concrete and membrane materials subject to the boundary conditions posed by the groundwater exposure in an undrained structure is emphasized. Finally, some recent results from currently ongoing research on such linings, particularly the hydraulic response of the rock mass and the long term behavior of the concrete and membrane materials are presented.