• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.5
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• pp.489-506
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• 2024

Excavation of tunnels below the groundwater table changes the hydraulic boundary conditions, causing flow towards the excavation face. Inflow into a tunnel is generally influenced by pre-excavation grouting, shotcrete lining, drainage system implementation, and the hydraulic deterioration of the drainage system. From the perspective of continuum theory, the groundwater inflow behavior due to excavation is very similar to the tunnel excavation behavior known as the convergence-confinement method. The groundwater inflow behavior due to tunnel excavation can be explained by the hydraulic convergence, while the behavior of shotcrete lining in limiting inflow can be inferred as hydraulic confinement. This study investigates the hydraulic convergence and confinement behavior using theoretical and numerical methods due to tunnelling. It is confirmed that the hydraulic convergence-confinement is exactly the same as the mechanical convergence-confinement concept. It is identified that the behavior is governed by the tunnel geometry, grout thickness and permeability, as well as the thickness and permeability of the support materials, such as shotcrete.

• Tunnel and Underground Space
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• v.11 no.2
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• pp.146-155
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• 2001

An inverse calculation method to obtain sectional forces, axial force and flexural moment of a tunnel concrete lining was developed by utilizing convergence measurements acquired at the maintenance stage. To monitor the behavior of the lining, DOCS system was applied to a subway tunnel section. The method was proved to be effective, yielding the same results as measured forces of buried instruments. Many effects such as vibration of sensors, vibration due to test train operation, the variation of temperature and high voltage were checked and a new management scheme for tunnel maintenance was proposed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.3
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• pp.209-215
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• 2004

Together with the requirements of tunnels, its construction methods and technologies have been pretty much developed, but frequent accidents happened under the constructions are just one of important problems which should be improved. To detect the potential hazardous factors in or ahead of time, speedy and accurate observation are absolutely required, but currently surveying method using tapes, level and total station, has been generally taken in measuring of tunnel convergence and crown. The purpose of this study is, as using of industrial photogrammetry system which is supplying more accuracy and speedy in the measure of tunnel convergence and crown. From the result of this study, we have got up to 1/20,000 accuracy and totally 6 minutes, from picturing 5 sections by one person to data edition, has been taken except setting targets.

• Tunnel and Underground Space
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• v.13 no.2
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• pp.77-86
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• 2003

The finite element method and statistics of the convergence measurement are useful method of the stability analysis of the tunnel adjacent to the pier. It is the purpose of the this case study to certificate of validity of the application of those methods. The safety of the pilot tunnel method and LW pre-grouting has been evaluated from the FEM analysis. The three-dimensional finite element method is carried out for the decision of the level of stress redistribution at the two-dimensional numerical analysis. An analysis of the convergence is carried out by the estimation of preceding convergence at tunnel excavation. F-examination is applied for this estimation. As results of that analysis, The F-value is from 10.81 to 158.74 and the coefficient of determination is from 0.82 to 0.99. An analysis of convergence is carried out by using regression analysis. Consequently, it is shown that the convergence can be modeled as following function C(t)=a[1-exp(-bt)].

• Journal of the Korean Society of Industry Convergence
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• v.10 no.2
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• pp.81-88
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• 2007

In case of an urban tunnel, the displacement of ground base controls the tunnel design because it is built on shallow and unconsolidated ground many times. There are more insufficiency to describe the ground movement which coincides in the measured result of the situ because the design of an urban tunnel is dependent on the method of numerical analysis used to the existing elastic and elasto-plastic models. We studied about the prediction for the ground movement of a shallow tunnel in unconsolidated ground, mechanism of collapse, and settlement. Also this paper shows comparison with the existing elastic and elasto-plastic model using the unlinear analysis of the strain-softening model. We can model the real ground movement as the increasement of ground surface inclination or occurrence of shear band by using strain-softening model for the result of ground movement of an urban NATM tunnel.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.4
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• pp.313-320
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• 2002

A 2-dimensional $k-{\varepsilon}$ numerical model was developed to explore the effects of vehicle movement, jet fan and wind speed for the ventilation of road tunnels. To consider the temperature distribution in the tunnel, the energy equation was solved with a source term of the energy exhausted from vehicles. Although the tunnel ventilation can be made by the piston effect of vehicle movement, an additional ventilation is necessary when a head wind is existing. Jet fans may assist the air flow in the tunnel. However, more efficient ventilation system should be necessary, because the exhaust gas from vehicles flow along the road surface and it cannot be diffused in the longitudinal tunnel.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.1-6
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• 2015

In this paper, we propose the LED(Light-Emitting-Diode) emergency lighting in a tunnel by using the thermoelectric devices. To achieve high generated power, thermoelectric device should be have high Seebeck coefficient and small contact area. Also, we reveal that a moderate heatsink required for high generated power. From the waste heat of LED tunnel lighting module (25W), the generated power was 0.062W by thermoelectric device, and it could illuminate for 1hour after charge the battery of emergency lighting during about 101hours.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.6
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• pp.637-652
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• 2012

The protector with the shape of '${\sqcap}$' in cross section can be set up in the tunnel, which can be constructed for enlargement of cross section, to keep traffic flow in the tunnel. It is impossible to install the rockbolt in the side wall of tunnel due to a limited space between the protector and cutting surface of side wall. The objective of this study is to suggest the optimum thickness of shotcrete lining without rockbolt on the side wall and to evaluate the stability of tunnel enlarged. Numerical analysis was performed to evaluate the displacement at the center of tunnel, the convergence of tunnel, and the stress in shotcrete lining in 4-lane NATM road tunnel enlarged from 3-lane NATM road tunnel. The vertical displacement at the center of tunnel and the convergence of crown in the tunnel with rockbolt in the side wall were almost similar to those in the tunnel without rockbolt in the side wall. The convergence of bench/invert and the stress in shotcrete lining without rockbolt on the side wall were greater maximum 0.57 mm and 1,300 kN/$m^2$ than those with rockbolt in the side wall. The increased convergence and the stress in shotcrete lining can be reduced in incerasing of thickness of shotcrete lining about 20% (5 cm) of standard thickness, 25 cm, of shotcrete lining.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.607-608
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• 2011

In this paper, we propose stopped vehicle detection algorithm in the tunnel. It is shown that our method distinguished objects from background estimated image, and then detected stopped vehicles efficiently based on the experimental analysis about the color information of their lamps. The simulation results show the detection rate is achieved over 95% in the tunnel image.

• Tunnel and Underground Space
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• v.17 no.5
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• pp.428-434
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• 2007

Displacement of tunnel face is important issues for the evaluation of tunnel safety. In this study, conventional convergence and displacement data measured from horizontal inclinometer were analyzed to investigate the trend and characteristics of tunnel deformation during construction. Trend of measured displacement agreed with general understanding of tunnel deformation prior to excavation. It shows that displacement measured from horizontal inclinometer can be used to preestimate the total deformation of tunnel.