• Proceedings of the KSR Conference
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• 2008.11b
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• pp.891-896
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• 2008

Behavior of the existing tunnel in the jointed rocks was affected by the adjacent slope excavation. In this study, large scale model tests were conducted. To investigate the tunnel distortion depending on the excavated slope angle and the joint dip of the ground performed model tests were numerically back analyzed. Consequently, as the joint dip and slope angle became larger, the tunnel distortion was tended to be larger. Ground displacement was also greatly dependent on the joint dip and the excavated slope angle, which indicated the possibility of the optimal slope reinforcement.

• Tunnel and Underground Space
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• v.17 no.2 s.67
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• pp.152-164
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• 2007

Recently as increasing the amounts of cargoes and passengers, it is necessary to improving railway capacity and speed. So the constructions of improving the existing railway line have been advanced. Sometimes the new railway tunnel is built to adjacent the existing railway line. Furthermore the new tunnel might be built near the existing facility within the tunnel width. In this case, it should be analyzed the influence of existing tunnel and if it is necessary, it should be taken the appropriate counterplan. The major analysis contents are follows. One is the influence on the existing tunnel by a blasting and train vibration and the other is stability problem of the existing tunnel by excavation of new tunnel. Therefore, we peformed the following analysis. Refer to a domestic and foreign standard and paper, the permitting level of blasting vibration is decided and the excavation plan of the new tunnel are designed. The numerical analysis is performed about the stability of the existing tunnel and new tunnel. The influence of the train vibration on tunnel is analyzed by the empirical equation.

• Journal of the Korean Geophysical Society
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• v.7 no.4
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• pp.313-324
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• 2004

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 Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.3052-3060
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• 2013

When planning to construct adjacent structure by the side tunnel, the criteria of safety zone of tunnel have been proposed. There are no specific theoretical basis regarding load conditions and the distance of structure and the geological strata and the conditions of adjacent structure's location, and the conditions applied load. Two and three dimensional numerical analysis preformed to prove the deformation of the ground and structures caused by the tunnel excavation and evaluated the correlation and the suitability of the tunnel's safety zone regarding the location of adjacent structures and the changes in the modulus of deformation. This paper proposed the safety zone's range is getting bigger as the modulus of deformation is higher. Also, it seems that the possible range of construction under constraints in the diagram of revalued safety zone significantly expands as shear failure line appears on the invert extension line below the spring line.

• Magazine of korean Tunnelling and Underground Space Association
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• v.18 no.3
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• pp.46-55
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• 2016

• Magazine of korean Tunnelling and Underground Space Association
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• v.8 no.3
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• pp.60-66
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• 2006

• Magazine of korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.39-45
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• 2022

• Magazine of korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.12-21
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• 2022

• Tunnel and Underground Space
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• v.22 no.1
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• pp.60-68
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• 2012

Focusing on the load tunnel, this study assessed the behavior of rock pillars with less than 0.5D of the minimized distance between the two horizontal tunnels by using a three dimensional numerical analysis. Based on a parameter affecting the behavior of rock pillars, this study evaluated different safety factors according to pillar width, depth and rock conditions. It turned out that as the pillar width increases, the current curve of safety factors in accordance with depth and rock conditions shows more of the nonlinear behavior. Judging from the minimum safety factor, the study suggested a design chart, working on the minimized distance between the two horizontal tunnels.

• Tunnel and Underground Space
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• v.23 no.2
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• pp.130-140
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• 2013

In this study, scaled model tests were performed to investigate the stability of twin tunnels with small clearance, where the pillar widths were 0.5D and 0.25D, respectively. The tunnels were supposed to be constructed in anisotropic weathered rocks with $30^{\circ}$ inclined bedding planes, and the model tests were conducted under the condition of lateral pressure ratio, 1. Six types of test models which had respectively different pillar widths and support conditions were experimented, where crack initiating pressures, maximum pressures, failure modes of pillar and deformation behaviors around tunnels were investigated. The models with wider pillar were cracked under higher pressure than the models with shallower pillar. The models with lining support were cracked under higher pressure and showed less tunnel convergence than the unsupported models. The models with both lining and pillar reinforcement were proved to be most stable among the tested models. In particular, as the model of 0.25D pillar width with only lining support showed shear failure of pillar according to the existing bedding planes, so both lining and pillar reinforcement were thought to be indispensable in that case of tunnel.