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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Korean Tunnelling and Underground Space Association
Journal Basic Information
Journal DOI :
Korean Tunnelling and Underground Space Association (KTA)
Editor in Chief :
Volume & Issues
Volume 13, Issue 6 - Nov 2011
Volume 13, Issue 5 - Sep 2011
Volume 13, Issue 4 - Jul 2011
Volume 13, Issue 3 - May 2011
Volume 13, Issue 2 - Mar 2011
Volume 13, Issue 1 - Jan 2011
Selecting the target year
Seepage-induced behaviour of a circular vertical shaft
Kim, Do-Hoon ; Lee, Kang-Hyun ; Lee, In-Mo ;
Journal of Korean Tunnelling and Underground Space Association, volume 13, issue 6, 2011, Pages 431~450
When a circular vertical shaft is constructed below the groundwater level, additional forces caused by groundwater flow besides horizontal effective stresses will act on the wall. The inward direction of the groundwater flow will be inclined to the vertical wall and its direction will change depending on the wall depth. In this paper, to figure out the effect of seepage forces acting on the circular vertical shaft, the slope of the inclined flow varying with the depth is divided into vertical and horizontal components to derive the coefficient of earth pressure considering the seepage pressure and to obtain the vertical stress by taking the seepage pressure into account. The control volume in this study is assumed to be the same with that of the dry ground condition within which the earth pressure is acting on the wall by the creation of the plastic zone during shaft excavation. An example study shows that the vertical stress increases by about 1.4 times and the horizontal earth pressure increases up to 2.5 times compared to the dry ground condition. The estimated values from the proposed equation considering seepage forces and the calculated values from numerical analysis with "effective stress plus seepage force" show similar values, which verifies appropriateness of the proposed equation to estimate the earth pressure under the seepage condition.
A study on the effective fire and smoke control in transverse oversized exhaust ventilation
Han, Sang-Pil ; Jeon, Yong-Han ;
Journal of Korean Tunnelling and Underground Space Association, volume 13, issue 6, 2011, Pages 451~462
The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume with scaled-model and simulation when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than
for the distance of the smoke moving which can limit the distance to 250 m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.
A study for application plan of rational residual water pressure on the tunnel linings
Jung, Kuk-Young ; Kim, Ji-Yeop ; Kim, Ji-Hun ; Moon, Hoon-Ki ;
Journal of Korean Tunnelling and Underground Space Association, volume 13, issue 6, 2011, Pages 463~499
Control of ground water is one of the most important factors for long-term operation of tunnel because most tunnels are located under the ground water level. In case of a drainage tunnel, there is no pore water pressure on the lining when the drainage system is properly working. After long-term operation, however, residual pore water pressure can be developed on the lining due to the deterioration of the drainage system. In this study, the water pressure distribution under obstruction condition of drainage material and conduit on the tunnel is numerically investigated using the ICFEP program and compared with the current value being applied to the residual water pressure for rational application plan of residual water pressure on the tunnel linings.
A study on critical strain based damage-controlled test for the evaluation of rock tunnel stability
Lee, Kang-Hyun ; Kim, Do-Hoon ; Park, Jeong-Jun ; Lee, In-Mo ;
Journal of Korean Tunnelling and Underground Space Association, volume 13, issue 6, 2011, Pages 501~517
In general, the tunnel stability during excavation is assessed by comparing measured displacements at roof and sidewall to control criteria. The control criteria were established based on the past experience that considered ground conditions, size of the tunnel cross section, construction method, supports, etc. Therefore, a number of researches on the control criteria using the critical strain have been conducted. However, the critical strain obtained from uniaxial compression tests have drawbacks of not taking damage in rock mass due to increase of stress level and longitudinal arching into account. In this paper, damage-controlled tests simulating stress level and longitudinal arching during tunnel excavation were carried out in addition to uniaxial compression tests to investigate the critical strain characteristics of granite and gneiss that are most abundant rock types in Korean peninsula. Then, the critical strains obtained from damage-controlled tests were compared to those from uniaxial compression tests; the former showed less values than the latter. These results show that the critical strain obtained from uniaxial compression tests has to be reduced a little bit to take stress history during tunnel excavation into account. Moreover, the damage critical strain was proposed to be used for assessment of the brittle failure that usually occurs in deep tunnels.
An experimental study on screw conveyor system of EPB shield TBM
Kim, Sang-Hwan ; Kim, Jin-Dae ; Park, Inn-Joon ;
Journal of Korean Tunnelling and Underground Space Association, volume 13, issue 6, 2011, Pages 519~530
The screw conveyor system installed in EPB Shield TBM chamber was manufactured in small scale for pilot test to investigate the tunnel muck hauling system that could control the earth pressure and support face thrust force. In this experimental study, there were three different test conditions that include screw angles, screw pitch, and screw RPM. Through analysis on test results based on the muck hauling amount per unit time from screw conveyor, the optimum conditions of screw conveyor were proposed to be efficiently performed by the muck processing system. Finally, this study provided the meaningful results such as optimum screw angle, screw RPM, and screw pitch for anti-reverse flow of muck hauling.
Rock TBM design model derived from the multi-variate regression analysis of TBM driving data
Chang, Soo-Ho ; Choi, Soon-Wook ; Lee, Gyu-Phil ; Bae, Gyu-Jin ;
Journal of Korean Tunnelling and Underground Space Association, volume 13, issue 6, 2011, Pages 531~555
This study aims to derive the statistical models for the estimation of the required specifications of a rock TBM as well as for its cutterhead design suitable for a given rock mass condition. From a series of multi-variate regression analysis of 871 TBM driving data and 51 linear rock cutting test results, the optimum models were newly proposed to consider a variety of rock properties and mechanical cutting conditions. When the derived models were applied to two domestic shield tunnels, their predictions of cutter penetration depth, cutter acting forces and cutter spacing were very close to real TBM driving data, showing their high applicability.
Effect of steel fibers on surface electric resistivity of steel fiber reinforced concrete for shield segment
Moon, Do-Young ; Lee, Gyu-Phil ; Chang, Soo-Ho ; Bae, Gyu-Jin ;
Journal of Korean Tunnelling and Underground Space Association, volume 13, issue 6, 2011, Pages 557~569
Steel Fiber Reinforced Concrete (SFRC) is widely used for tunnel structures such as shotcrete and segments. Corrosion of steel fibers and steel reinforcements may affect on the long-term durability of the concrete structures with steel fibers and reinforcement. Therefore, a study on the feasible method to evaluate corrosion possibility and permeability of the concrete structures is required. This experimental study examines the effect of steel fibers and internal reinforcement on the surface resistivity. Steel fiber mix ratio and corrosion of internal reinforcement were considered as variables. In the results, steel fibers significantly reduce the surface resistivity due to those conductive characteristic. In the case of 3% mix ratio, it was difficult to evaluate rate and permeability of corrosion due to the great reduction of resistivity by mixing of steel fibers.