• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.2
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• pp.199-207
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• 2003

Tunnel modelling in the field of geotechnical engineering essentially requires models of tunnelling machines and the simulation of tunnelling processes to clarify the detailed behaviour of tunnel construction. Modern advanced mechatronics, including construction processes, machinining and control technologies, are making it possible to fabricate such models. These technologies, however, are essentially developed in a gravity field condition and are needed to examine in a 1g or cenrifuge field condition. This paper presents the simulation method for tunnelling processes and the design method for tunnelling machines with special reference to the problem of earth pressure acting on the lining of a shield tunnel. The paper then introduces and verifies the design method for tunnelling machines in the 1g field by means of checking the reproduceability of experiment data and their comparison with data in the field.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.85-100
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• 2004

In this paper the historical and technological developments of rock TBM and the technical classification of the machines proposed by ITA (International Tunnelling Association) are initially presented. Then the general criteria for the TBMs selection are discussed and at the end the limiting geological conditions for the application of TBMs are analysed.

• Magazine of korean Tunnelling and Underground Space Association
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• v.4 no.4
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• pp.49-53
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• 2002

향수직굴착용장비로는 승갱굴착기(Raise Boring Machine)과 레이스크라임버(Raise Climber)로 나눌 수 있다. 이장에서는 수직굴착용장비가 다수 있으나 일부장비를 간략하게 소개하며, 추후 공법에 대한 설명할 기회가 주어진다면 좀더 다양한 장비 및 공법에 대해 자세히 기술하도록 하겠다.

• Tunnel and Underground Space
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• v.23 no.3
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• pp.161-168
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• 2013

Recently, the application of High-Power mechanized tunnelling technology has been expended around the world. Especially, High-power Modern TBM machines are used in a successful results. Essential for the great success of this modern TBM in difficult rock conditions are based on the development of machine power, suitable better cutter developments, and also developed assesment technology regards on the extensive site investigations. OPP (Owner Procurement Process) system is a proven alternative contract delivery method that is potentially applicable to many tunnel projects. Using the OPP, the owner specifies and procures the TBMs and tunnel lining in advance of the tunnel contract procurement and provides TBM to a tunnel contractor with a goals of reducing project risks and accelerating project schedule. Depending on the blasting vibrations and noises, mechanized tunnelling will be more important particularly in city areas.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.6
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• pp.599-614
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• 2014

When tunnelling with TBM (Tunnel Boring Machine), accessibility to tunnel face is very limited because tunnel face is mostly occupied by a bunch of machines. Existing techniques that can predict ground condition ahead of TBM tunnel are extremely limited. In this study, the TBM Resistivity Prediction (TRP) system has been developed for predicting anomalous zone ahead of tunnel face utilizing electrical resistivity. The applicability and prediction accuracy of the developed system has been verified by performing field tests at subway tunnel construction site in which an EPB (Earth Pressure Balanced) shield TBM was used for tunnelling work. The TRP system is able to predicts the location, thickness and electrical properties of anomalous zone by performing inverse analysis using measured resistivity of the ground. To make field tests possible, an apparatus was devised to attach electrode to tunnel face through the chamber. The electrode can be advanced from the chamber to the tunnel face to fully touch the ground in front of the tunnel face. In the 1st field test, none of the anomalous zone was predicted, because the rock around the tunnel face has the same resistivity and permittivity with the rock ahead of tunnel face. In the 2nd field test, 5 m thick anomalous zone was predicted with lower permittivity than that of the rock around the tunnel face. The test results match well with the ground condition predicted, respectively, from geophysical exploration, or directly obtained either from drilling boreholes or from daily observed muck condition.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.6
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• pp.623-641
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• 2020

About 5 km length of tunnels were constructed by mechanized tunnelling method using closed type shield TBM. In order to avoid construction delay problems for ensuring timely electricity transmission, it is necessary to increase the prediction accuracy of the excavation process involving machines according to rock mass types. This is important to corroborate the project duration and optimum operation for various considerations involved in the machine. So, full-scale tunnelling tests were performed for developing the advance rate model to be appropriately used for 3.6 m diameter shield TBM. About 100 test cases were established and performed using various operational parameters such as thrust force and rotational speed of cuttterhead in representative uniaxial compressive strengths. Accordingly, relationships between normal force and penetration depth and, between UCS and torque were suggested which consider UCS and thrust force conditions according to weathered, soft, hard rocks. Capacity analysis of cutterhead was performed and optimum operational conditions were also suggested based on the developed model. Based on this study, it can be expected that the project construction duration can be reduced and users can benefit from the provision of earlier service.

• Tunnel and Underground Space
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• v.2 no.1
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• pp.177-189
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• 1992

As tunnel becomes longer and larger, TBM has become one of the most popular methods of excavatio in rock. This paper describes the degree of operation the degree of availability and penetration rate of TBM and TBE applied in Namsan roadway tunnelling site. Net penetration rate was 1.62m/hr for TBM and 0.72m/hr for TBE. Net penetration rate showed no direct relation to daily advance or penetration time, but the lower bound of penetration rate could be obtained from the relation with daily advance. For both of TBM and TBE, the degree of operation and the degree of availability were 33.8% and 68.6% respectively. Life time of normal cutter was $310m^3$ for TBM and $194m^3$ for TBE, while that of center and gauge cutter was about $50m^3$. When the two machines were compared, TBM showed 80% higher penetration rate, and 40% shorter life time of cutter.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.221-243
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• 2023

The use of roadheaders has been increasing to mitigate the problems of noise and vibration during tunneling operations in urban area. Since lack of experience of roadheader for hard rock, the selection of appropriate machines and the evaluation of cutting rates have been challenging. Currently, empirical models developed overseas are commonly used to evaluate cutting rates, but their effectiveness has not been verified for domestic rocks. In this paper, a comprehensive literature review was conducted to assess the rock cutting force, cutterhead capacity, and cutting rate to select the appropriate machine and evaluate its performance. The cutterhead capacity was reviewed based on the literature results for the site. Furthermore, a new empirical model and simplified method for predicting cutting rates were proposed through data analysis in relation to operation time and rock strength, and compared with those of the conventional model from the manufacturer. The results show good agreement for high strength range upper 80 MPa of uniaxial compressive strength.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.5
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• pp.355-374
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• 2022

Soil conditioning improves the performance of EPB (earth pressure balance) shield TBMs (tunnel boring machines) by reducing shear strength, enhancing workability of the excavated soil, and supporting the tunnel face during EPB tunnelling. The mechanical and rheological behavior of the excavated muck mixed with additives should be properly evaluated to determine the optimal additive injection condition corresponding to each ground type. In this study, the laboratory pressurized vane test apparatus equipped with a vane-shaped rheometer was developed to reproduce the pressurized condition in the TBM chamber and quantitively evaluate rheological properties of the soil specimens. A series of the pressurized vane tests were performed for an artificial sand soil by changing foam injection ratio (FIR) and polymer injection ratio (PIR), which are the injection parameters of the foam and the polymer, respectively. In addition, the workability of the conditioned soil was evaluated through the slump test. The peak and yield stresses of the conditioned soil with respect to the injection parameters were evaluated through the rheogram, which was derived from the measured torque data in the pressurized vane test. As FIR increased or PIR decreased, the workability of the conditioned soil increased, and the maximum torque, peak stress, and yield stress decreased. The peak stress and yield stress of the specimen from the laboratory pressurized vane test correspond to the workability evaluated by the slump tests, which implies the applicability of the proposed test for evaluating the rheological properties of excavated soil.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.511-524
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• 2016

Since a room-and-pillar underground structure is characterized by its grid-type array of room and pillar, its economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill-and-blast method as a excavation method for a room-and-pillar underground structure was examined. In addition, the parallel excavation sequence was considered as the main sequence of a room-and-pillar underground structure. Sequences of mucking and support installation were derived to estimate the total excavation cycle by taking the case of a road tunnel into consideration. From the excavation cycle of room-and-pillar underground structure, the relationship between available maximum and minimum numbers of jumbo drill machines depending on the number of faces in operation was suggested.