• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.53-68
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• 2011

This paper presents the fundamental parameters for designing the NATM Composite Lining to be used in NATM tunnel construction. Firstly, the concept of NATM Composite Lining behaviour is introduced and reviewed in construction-performance. For the fundamental study, the optimal mix ratio tests and backfill material property tests to develop high-quality composite lining (PC panel lining) are fundamentally carried out. And the light-weight foamed mortar which is used for backfill material is developed. Full-scale loading tests to verify a performance of the NATM Composite Lining is also performed. From this research, it is clearly found that the NATM Composite Lining is very applicable method to considerably increase the stability and constructability of tunnel structure.

• Explosives and Blasting
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• v.41 no.4
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• pp.9-16
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• 2023

To compare the global warming impact of the TBM and NATM method, which are representative tunnel excavation methods, a life cycle assessment was performed for each method. Life cycle assessment should compare the sum of carbon emissions by considering the pre-manufacturing stage, product manufacturing stage, usage stage, and disposal stage. However, access to TBM (Tunnel Boring Machine) manufacturing and disposal data is limited, so I had no choice but to focus on the analysis for the usage stage. In general, carbon emissions during the pre-product manufacturing stage and product manufacturing stage often exceed 90% of carbon emissions throughout the entire process. Therefore, since it is difficult to achieve the analysis goal only by comparing the usage stage, the analysis scope was expanded, and carbon emissions for the process were calculated for the NATM method with access to manufacturing data. As a result of comparing the relative impact on global warming, the carbon emissions of the TBM method were found to be higher than those of the NATM method even though TBM method was only considered for the usage stage. So there it is, the NATM method can be seen as environmentally friendly in the future when considering the impact of climate change (global warming), which has recently attracted attention among environmental impact fields.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.69-84
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• 2011

This paper presents the applicability of NATM Composite Lining method in domestic tunnel construction sites. Firstly, in order to produce high quality PC Panel, optimal steam curing condition is reviewed. And in preparation for fire inside the tunnel, the fire-resistance test of PC Panel is carried out. The constructability of NATM Composite Lining method and the drainage ability of light-weight foamed mortar is also evaluated through field construction test. And PC Panel combination program is developed to calculate the quantity of PC Panel efficiently. Besides, economic evaluation for NATM Composite Lining method is conducted. From this research, it is clearly found that NATM Composite Lining method is applicable to domestic tunnel construction site.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.4
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• pp.437-447
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• 2009

It is easily found by several references of NATM that the cracks on the lining concrete of NATM are more developed than those of the conventional tunnel methods. Based on the results of research, the new method is proposed to control and protect the axial cracks on the tunnel linings. Also, the efficiency of proposed method is evaluated using the Distinct Element Method.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.69-79
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• 2012

This pre-supported nail method is able to decrease ground displacements more than NATM because this method reinforces ground with grouted steels before tunnel excavation. Therefore this method has advantage of being able to increase the stability and workability. This study presents applicability of pre-supported nail method with case of site measurement for shallow tunnel composed with high groundwater level and unconsolidated soil, performs this research the mechanism of new supporting system is compared with the conventional existing supporting system in terms of soil reinforcement. NATM has characteristics that construction stage displacement of the apparent height difference is observed in the step of divided excavation processing. Otherwise it is analyzed that pre-supported nail method is not sensitive in the displacement problem of excavation processing in comparison to NATM. It is found that this method is very applicable in shallow depth tunnel such as portal area, tunnel in soil and weak zone without arching effect.

• Explosives and Blasting
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• v.10 no.2
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• pp.3-7
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• 1992

Concerning to Taeku city subway construction project(1-4 site), the original design was adapted NATM Tunnel method to the 8 meter thickness of overburden. Surveyor checked sity and design material and finally decided to change into Open Cut method because overburden is not only below 1 1/2 times thickness of comparate Tunnel width but there is no traffic conjunction in job site.

• Geotechnical Engineering
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• v.1 no.1
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• pp.31-46
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• 1985

An extensive program of tunnel instrumentation has been Implemented in the construction of the Seoul Subway Line 3 and 4, in which the NATM was adopted as the main tunnelling technique. Among more than ten instrumented sections in the downtown area, five representative test sections were selected for analysis in this study, with an emphasis on the surface settlement and crown settlement. Variations of the surface and crown settlement. Variations of the governing factors, such as ground conditions, tunnel geometry, and construction conditions are described in this paper. Possible mechanisms for ground deformations occurring at different stages of tunnel construction are formulated, based on overall interpretation of the field observations and data obtained.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.4
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• pp.285-303
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• 2023

Interest in building underground spaces is increasing for the creation of downtown infrastructure and efficient space utilization. A representative method of utilizing underground space is a tunnel, and in addition to road tunnels, the construction of utility tunnels such as power conduits and utility conduits is gradually increasing. The current basic tunnel construction method can be divided into NATM (New Austrian Tunnelling Method) and TBM (Tunnel Boring Machine). The NATM is a reliable method, but it is accompanied by vibration and noise due to blasting. In the case of the TBM excavation method, there are disadvantages in terms of construction period and construction cost, but it is possible to improve economic feasibility by introducing appropriate complementary methods. In this study, a blasting method was develop using the NATM after TBM pre-excavation using the protective shield method. This is a method that compensates for the disadvantages of each tunnel construction method, and is expected to reduce construction costs, blasting vibration, and noise. In order to review the performance of the developed method, an experiment was conducted to evaluate the performance of explosion-proof tube to which a protective shield scale model was applied, and the impact of blasting vibration of the protective shield method was analyzed.

• Explosives and Blasting
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• v.11 no.3
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• pp.73-77
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• 1993

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.757-763
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• 2022

In the NATM tunnel construction method for urban subway and underpass construction, various causes of disaster exist. In this study, in order to analyze the importance of disaster influencing factors during NATM tunnel excavation, the possible risk factors were analyzed through prior research such as drilling, charging and blasting, It was divided into the work items of wrinkle treatment, pumice cleanup, and support materials. Next, the final 21 detailed measurement indicators were selected through the FGI survey of related experts, and AHP (Analytic Hierarchy Process) analysis were conducted. As a result, it was found that the workers involved in the tunnel construction were the most influential disaster influencing factor.