• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1090-1095
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• 2004

Umbrella Arch Method(UAM), among others. is commonly applied to increase the facial stability during tunnel excavation and, depending on the field condition, additional reinforcement techniques can be used simultaneously. UAM, together with grouting method, is normally used to reduce ground permeability and improve stability of the tunnel by inserting a series of steel pipes into the ground around the crown inclined to the longitudinal axis of the tunnel. However. there has not been much rigorous study on the effectiveness of UAM, and most of UAM installations depend on empirical judgement rather than on engineering calculation, .In this study, the effectiveness of UAM is demonstrated based on the constitutive relationship involving UAM derived from the mechanics of composite material, and the numerical investigation is compared with small scale experiments on the tunnel reinforcement.

• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.2
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• pp.22-31
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• 2000

This study aimed at investigating the influence of tunnel length and area, drag coefficient, train velocity on the characteristics of ventilation in railway tunnel. The modified Subway Environment Simulation(SES) computer program has been used to calculate the flow velocity and longitudinal emission concentration with various condition. According to a series of numerical simulation, the influence of various parameter on maximum air flow velocity, purging length and emission concentration are estimated.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.406-413
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• 1999

A compression wave is generated by the high speed train which enters a tunnel, and it propagates along the tunnel. When the compression wave emerges from the exit of the tunnel, it causes an impulsive noise, and the strength of the impulsive noise depends on the pressure gradient of the first compression wave. So it needs to reduce the pressure gradient for the minimization of impulsive noise. The entrance hood is used for the reduction of the pressure gradient. In the present study, the pressure transients were numerically calculated for three shapes of hood, In order to validate the numerical simulation, the pressure and pressure gradient were compared with the experimental data of moving model rig. The calculation results won well agreed with the experimental data, and also showed that the hood had an effect on the pressure gradient of the tunnel inside.

• International Journal of Railway
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• v.1 no.4
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• pp.169-174
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• 2008

Experimental study has been conducted to clarify the internal and external pressure variation characteristics for KTX(Korea Train eXpress) passing through tunnel. Abrupt pressure variation gives rise to the ear-discomfort for passenger and fatigue for car body. In this study, the internal and external pressure variation are measured by using KTX real train experiment and on-board portable data acquisition system in Gyeongbu high speed commercial line. The tunnels from 200 m to 4000 m in length are chosen for the investigation of tunnel length effects. From the results of experiment, the internal pressure variation rate for all the test tunnels is lower than the standard criteria of 200 Pa/s. And, the critical tunnel lengths for pressure wave pattern are classified into 7 groups by using the theoretical L-t diagram analysis.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.26-31
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• 2004

A study is conducted to clarify internal and external pressure variation of passenger cabin for KTX. These pressure variation may give rise to the ear-discomfort for passenger and fatigue for carbody. In this study, the pressure variation of interior, gangway and exterior of KTX passenger car is measured by using the atmospheric pressure sensors and portable data acquisition system. The tunnel from 4000m to 200m in length are chosen far the investigation of tunnel length effects. From the results of experiment, the pressure variation of interior per second is under the ear-discomfort limitation in all of tunnel. And, We found that there are similar patterns of exterior pressure variation for each critical tunnel length. These results generally agree to RTRI's experimental result fur Shinkansen.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.12a
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• pp.1-22
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• 1998

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.726-733
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• 2005

It is very important to pay careful attention to construction of earthwork/tunnel transition zone for railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. In this study, performance of transition zone was investigated through the field tests. The wheel loads and sleeper settlement were measured after installing field testing sections.

• Structural Engineering and Mechanics
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• v.64 no.3
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• pp.293-299
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• 2017

Submarine collisions is one of the major hazardous factor for Submerged Floating Railway Tunnel (SFRT) and this study presents the safety evaluation for submarine collision to SFRT by using theoretical approach. Simplified method to evaluate the collision safety of SFRT was proposed based on the beam on elastic foundation theory. Firstly, the time history load function for submarine collision was obtained by using one-degree-of-freedom vibration model. Then, the equivalent mass and stiffness of the structure were calculated, and the collision responses of SFRT were evaluated. Finite element analysis was conducted to verify the proposed equations, and it can be found that the collision responses, such as deflection, and acceleration, agreed well with the proposed equations. Finally, derailment condition for high speed train in SFRT due to submarine collision was proposed.

• Geomechanics and Engineering
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• v.20 no.3
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• pp.267-273
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• 2020

Solutions of the water pressure and groundwater inflow distribution along the tunnel perimeter in a half-infinite aquifer were investigated considering the conditions of the constant head and constant water pressure. It is assumed that the circular tunnel is buried in a fully saturated, homogeneous, isotropic and half-infinite space. Coordinate transformation technique was adopted, the problem of solving the control equations of water pressure in the Cartesian coordinate was transformed to that in the bipolar coordinate system, which can significantly simplify the derivation procedure of the water pressure and inflow distribution. The validation results show the accuracy and advantage of the proposed approach.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.6
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• pp.559-570
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• 2013

High speed railway can transport large quantity of people and commodities in a short time and has become one of the most desirable and environmentally friendly transportation. However, it is hard to have a complicated route for high speed railways, construction of tunnels is essential to pass through a mountain area. When a high speed train enters a tunnel, pressure wave is created in a tunnel and the wave causes micro pressure wave and discomfort to passengers. In order to alleviate pressure wave in a tunnel, constructing a vertical shaft is one of the most efficient ways. This study represents a numerical analysis module, which takes into account the effect of a vertical shaft in a tunnel. The module can be used in a numerical program (TTMA) specialized for aerodynamics in a tunnel, and it was validated by comparing numerical results with various measurements in Emmequerung tunnel and results from numerical analysis using Fluent.