• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2008.03a
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• pp.25-40
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• 2008

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.494-504
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• 2008

Successful design, construction and maintenance of NATM tunnel demands prediction, control, stability estimation and monitoring of surface settlement, gradient and ground displacement with high accuracy. Back analysis using measured data and forward analysis have been and are indispensable tools to achieve this goal. Sakurai provided the hazard warning levels for assessing the stability of tunnels using the relation of critical strain and apparent Young's modulus. This paper performed the estimation of tunnel stability on construction. Firstly, the apparent Young's modulus concept and back analysis method is introduced for the assessment of tunnel safety during excavation a brief framework. Secondly, this paper deals with case study using "Apparent Young's modulus" and "Back analysis" for the purpose of estimating the stability of NATM tunnel in Korea. Finally, a general method that can be estimated the tunnel stability discussed by a flow chart.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.1
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• pp.73-88
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• 2005

Three approaches presently used for the design of underground structures in rock mass are quantitative rock mass classification system, classification systems based on the behavior of the rock mass during excavation and general qualitative procedures for the design process. In this study their characteristics and shortcomings are discussed, and Austrian guideline for tunnel design/construction, that was proposed to solve the problems with these methods, are introduced and compared. For technically sound and economic tunnel construction, a flexible design and construction procedure is needed to cope with uncertain ground and boundary condition, and also actual ground condition should be predicted through feedback of geotechnical information obtained during construction.

• Tunnel and Underground Space
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• v.15 no.2 s.55
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• pp.102-110
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• 2005

○ ○ tunnel that is located at Iksan - Jangsu freeway ○ ○, has collapsed during construction at the valley with shallow depth. Although, the site investigations, such as TSP, drilling exploration and so of indicated the presence of discontinuities in this section. The RMR was upgraded and the construction were carried out because that not only actual rock qualities were relatively good during construction but also the tunnel foe was stabilized. However, the tunnel was collapsed at the same time blasting of full face, and surface and underground water was infiltrated due to the settlement of the upper part of the tunnel face. To restore the collapsed section, 3-d tunnel stability analysis was performed and suitable reinforcement methods were chosen. The cavity of the upper tunnel face was stabilized by means of UAM and ALC injection. And the settlement was restored using L.W grouting method.

• Geotechnical Engineering
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• v.24 no.2
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• pp.35-45
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• 2008

• Geotechnical Engineering
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• v.33 no.1
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• pp.26-37
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• 2016

• Proceedings of the Korean Geotechical Society Conference
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• 1996.10a
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• pp.51-60
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• 1996

• Geotechnical Engineering
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• v.28 no.9
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• pp.17-29
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• 2012

• Journal of the Korean Geosynthetics Society
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• v.9 no.2
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• pp.41-50
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• 2010

The concrete lining of a tunnel constructed by NATM used to be regarded as facing material which does not support any load from the surrounding ground. But the recent appraisal of the decrepit tunnels revealed that rockbolts and shotcrete deteriorate with time resulting in loss of supporting capability. Consequently, concrete lining has to support part of the load which used to be supported by rockbolts and shotcrete, and thus should be regarded as the final supporting structure in a tunnel. One of the common, and perhaps the most serious problem in concrete lining is the longitudinal cracks taking place at the tunnel crown. The longitudinal cracks, mostly related to the construction procedures, can be developed by many reasons such as the lack of thickness, wrong materials, bad curing environment, and excessive external forces. Many efforts has been made to control and suppress these cracks but efficient and economic way is yet to be found. For efficient crack control in concrete lining, reinforcement by composite fibers, which is the mixture of steel fiber and nylon fiber, is suggested in this study.

• 기계와재료
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• v.21 no.4
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• pp.96-105
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• 2010

도로 및 철도는 차량의 고속화와 신속한 물류의 유통을 위해 직선 및 수평화가 절실하게 요구되며, 국내 건설구간의 약 50~70%가 산악지형으로서 터널공사가 필수적으로 요구된다. 국내터널굴착은 주로 발파에 의한 NATM(New Austrian Tunneling Method)으로 공사가 이루어지고 있으나, 굴착효율이 낮으며 안전사고의 위험성이 높다. 해외에서는 급속한 시공을 위하여 TBM(Tunnel Boring Machine)의 적용 사례가 증가하고 있다. 그러나 국내에는 TBM에 대한 연구가 전무한 상태이고, TBM 터널의 설계 시공 기술과 경험이 미흡하다. 최근 대도시의 지하터널과 장대터널의 수요가 증대되어 TBM터널시공 기술과 TBM장비의 국산화가 절실하게 요구되고 있다. 본고에서는 국내외 주요 TBM 시공현황과 전망을 정리하여 TBM 터널 기술의 확보가 매우 시급함을 상기시키고자 하였다.