• The Journal of Engineering Geology
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• v.16 no.3 s.49
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• pp.265-273
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• 2006

Face mapping during tunnel construction is useful and critical to predict the characteristics and stability condition of following tunneling sections and to select optimum support pattern. Therefore, a detailed geological survey of the tunnel faces, as important as a routine underground survey and a RMR evaluation, should provide critical information of the tunnel face condition in terms of the engineering geological condition and the safety of working environment for the following tunneling section. But the results of the face investigation have not been applied satisfactorily during tunneling due to limitation of technique, experience and time. This study analyze problems of face mapping in tunnel construction site by using statistical results of face mapping sheets obtained from completed tunnels, and suggest several opinions to improve face mapping during tunnel construction.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.300-302
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• 2007

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.3
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• pp.257-272
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• 2016

It is usually not an easy task to counter-measure on time and appropriately when confronting with troubles in mechanized tunnelling job-sites because of the limitation of available spaces to perform those actions with the existence of disk cutter, cutter head, chamber and other various apparatus in Tunnel Boring Machine (TBM). So, it is important to predict the ground condition ahead of a tunnel face during tunnel excavation. Efforts have been made to utilize geophysical methods such as elastic wave survey, electromagnetic wave survey, electrical resistivity survey, etc for predicting the ground condition ahead of the TBM tunnel face. Each prediction method among these geophysical methods has its own advantage and disadvantage. Therefore, it might be needed to apply several geophysical methods rather than just one to predict the ground condition ahead of the tunnel face in the complex and/or mixed grounds since those methods will compensate among others. The problem is that each prediction method will give us different answer on the predicted ground condition; how to combine different solutions into a most reasonable and representative predicted value might be important. Therefore, in this study, we proposed a methodology how to systematically combine each prediction method utilizing probabilistic analysis as well as analytic hierarchy process. The proposed methods is applied to a virtual job site to confirm the applicability of the model to predict the ground condition ahead of the tunnel face in the mechanized tunnelling.

• Explosives and Blasting
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• v.31 no.2
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• pp.40-49
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• 2013

To predict ground conditions ahead of the tunnel face, seismic refraction survey has been widely used. But due to the development in seismic equipment and techniques, tomography using borehole and others are actively applied in recent years. This study has a purpose to prevent stability problems during excavation and construction of tunnels by predicting unfavorable ground conditions such as fault, fractured zone and rock quality variation zone ahead of the tunnel face using TSP survey equipment. In this study, the validity of predicting ground conditions ahead of tunnel face by TSP survey has been evaluated through the case study in the road construction site.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.649-651
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• 2007

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.545-553
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• 2008

Face mapping and displacement monitoring during tunnel construction are the most influential information for the stability assessment of ground and around structures. Especially, the result of face mapping and displacement analysis is essential to the excavation and support design in NATM which is based on the drilling and blasting. However, there have not been so many studies to put those useful information into practice for decision-making process during construction. The study reviewed the tunnel behaviour based on the RMR rating and displacement monitoring when the geological condition of rock mass varies inevitably. The study analysed the crown settlement using convergence equation in order to compensate the disparity induced by the location and time of measurement and found a distinct relation between the geological condition and the line of influence. As a result of analysing the various parameters related to the tunnel convergence according to the geological condition, the study suggested the basic knowledge about the relation between face mapping and displacement behaviour of tunnel.

• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.463-473
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• 2005

Because of using the same rating ranges for every rock types the RMR or the Q-system could not usually consider local geological characteristics They also could not present sufficiently the engineering anisotropy of rocks. The canonical correlation analysis was carried out with 3 kinds of face mapping data obtained from granite, sedimentary rock and phyllite in order to clarify a discrepancy between rock types. According to analysis results, as a type of rocks changes, RM factors have different influences on the total rating of RMR.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.343-351
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• 2014

Tunnel face mapping plays an important role in risk analysis and infrastructure support decisions during tunnel construction. In this study, a digital mapping system using a mobile device is employed instead of existing face-mapping methods that rely upon face mapping sheets. The mobile device is then connected to the main server in the field, where a tunnel-specific database is compiled automatically. This information provides real-time feedback on the tunnel face to construction personnel and engineers, thus allowing for rapid assessment of tunnel face stability and infrastructure needs. The Douglas-Peucker algorithm, among others, is employed to resolve problems arising from the detailed mapping and speed problem by data accumulation. This system is expected to raise program optimization through field verification and additional functional improvements.

• Geotechnical Engineering
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• v.39 no.2
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• pp.51-77
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• 2023

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2001.03a
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• pp.132-138
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• 2001

홍콩 HMRT(Hongkong Mass Railway Tunnel) 지하철 공사현장에서는 터널굴착시 나타난 고경사절리로 인해 상당한 여굴이 발생하였다. 이에 대한 원인을 규명하기 위하여 각 터널별로 발생한 여굴의 양과 위치 등을 조사하고 이를 입찰설계단계에서 이루어진 시추공조사와 굴착단계에서의 막장검측에 의한 지질조건과 서로 비교, 분석하였다. 터널굴착에서 발생하는 여굴은 막장의 고경사 절리의 분포와 방향에 의해 영향을 받았으며, 암반조건 RQD, Q'와도 밀접한 관계를 가지는 것으로 나타났다. 본 현장의 분석에 따르면 터널설계시 고경사절리의 존재여부 및 분포, 방향성 등을 면밀히 조사하고 해석하여 사전에 여굴의 발생 가능성을 확인하는 것이 필요하다.