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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 16, Issue 6 - Nov 2014
Volume 16, Issue 5 - Sep 2014
Volume 16, Issue 4 - Jul 2014
Volume 16, Issue 3 - May 2014
Volume 16, Issue 2 - Mar 2014
Volume 16, Issue 1 - Jan 2014
Selecting the target year
A study on applications of the natural ventilation pressure(NVP) in local tunnels
Kim, Hyo-Gyu ; Yoo, Ji-Oh ; Lee, Chang-Woo ;
Journal of Korean Tunnelling and Underground Space Association, volume 16, issue 3, 2014, Pages 269~285
DOI : 10.9711/KTAJ.2014.16.3.269
In spite of the importance of the natural ventilation pressure(NVP) in tunnels for the optimal design of the ventilation system, there have been only few studies on the NVP because its measurement and quantitative analysis are not straightforward. This study aims at quantifying the amount of the NVP with the terrain and meteorological data for the local major tunnels. And ultimately this will lead to developing the guidelines for quantifying and applying NVP for the optimal design of tunnel ventilation system. 22 local tunnels in the major routes are studied for the NVP quantification. NVP derived from the meteorological data is in the range of 20~140 Pa, while NVP estimated from the terrain data ranges from 20 to 200 Pa. Since the jet fan pressure is about 10~15 Pa per unit, the minimum level of NVP expected in the local tunnels is larger than the pressure rise by one unit of the ordinary jet fan. This implies that NVP in local tunnels should be quantified and be taken into consideration for the economic and safe ventilation design. The barometric pressure difference between tunnel portals is found to be the most influential factor, accounting for 61% of the NVP, while the wind pressure acting on the portals and the chimney effects occupy 22% and 17%, respectively.
Performance evaluation of SFRC for tunnel segments based on large beam test
Moon, Do-Young ; Roh, Hwasung ; Chang, Soo-Ho ; Lee, Gyu-Phil ; Bae, Gyu-Jin ;
Journal of Korean Tunnelling and Underground Space Association, volume 16, issue 3, 2014, Pages 287~298
DOI : 10.9711/KTAJ.2014.16.3.287
In order to develop SFRC TBM tunnel segment, evaluating the SFRC mixture was conducted through flexural tests of SFRC beams without ordinary steel reinforcement in this study. Considered variables were compressive strengths of SFRC, aspect and mix ratio of steel fibers and total 16 specimens were fabricated and tested until failure. The load-vertical displacement results demonstrates that the effect of aspect ratio is minor when compared to results form small beam test(Moon et al, 2013). A SFRC beam resists the vertical load until the width of crack reaches to 7 mm due to steel fibers across cracked surfaces. Moreover, it is found that flexural moment estimated by equation of TR No. 63(Concrete Society, 2011) is useful for prediction of nominal strength for SFRC structure. From the investigation of fiber distribution in cracked section, it is found that dispersion improved in actual size beam compared to in standard small beam for evaluation of flexural strength.
Assessment of minimum pillar width and reinforcement of parallel tunnel using numerical analysis and field monitoring
An, Yong-Koan ; Kong, Suk-Min ; Lee, Yong-Joo ;
Journal of Korean Tunnelling and Underground Space Association, volume 16, issue 3, 2014, Pages 299~310
DOI : 10.9711/KTAJ.2014.16.3.299
Nationally, tunnel and underground constructions are necessary for the environmental sustainability and the efficient use of land space. For the importance of eco-friendly circumstances, 2-arch or large road tunnel has been designed so far. However, such a 2-arch or large tunnel has problems in terms of cost, constructability, construction period, and maintenance. Therefore, in this study, tunnel behavior and stability of rock pillar according to the pillar width and cover depth for parallel tunnels are investigated by performing FE analysis and using empirical formula. According to the results, Rock pillar is reinforced for distributed vertical load by Tie-Bolt due to unpredicted ground deformation, and the reinforced rock pillar's behaviour from the FE analysis shows a quite good agreement with field measurement. According to ground conditions, if the pillar width of the parallel tunnels is reduced, it can be more efficient in use of the tunnel space compared to previous tunnels.
Fire resistance assessment of high strength segment concrete depending on PET fiber amount under fire curves
Choi, Soon-Wook ; Lee, Gyu-Phil ; Chang, Soo-Ho ; Park, Young-Taek ; Bae, Gyu-Jin ;
Journal of Korean Tunnelling and Underground Space Association, volume 16, issue 3, 2014, Pages 311~320
DOI : 10.9711/KTAJ.2014.16.3.311
High strength concrete is not only vulnerable to the occurrence of spalling which generates the loss of cross-section in concrete structures but produces faster degradation in its mechanical properties than normal strength concrete in the event of fire. This study aims to evaluate fire resistance of high strength segment concrete with PET fibers mixed to prevent spalling under ISO834 (2hr) and RABT fire curve. As results, the samples without PET fibers show the concrete loss up to the depth of about 8 cm and 9.5 cm from the surface exposed to fire under ISO834 and RABT fire curve respectively. The samples mixed with PET fiber of 0.1% show no spalling under ISO834 fire curve and the spalled thickness of 6.5 cm under RABT fire curve after the fire tests. Finally, the sample mixed with PET fiber of 0.2% shows no spalling under RABT fire curve. The results indicate that the suitable amounts of PET fiber for securing fire resistance performance of this high strength segment concrete are 0.1% under ISO834 fire curve and 0.2% under RABT fire curve. However, even though spalling does not occur, it is necessary to repair the deterioration of concrete up to 4 cm from the surface exposed to fire after fire.
Development and implementation of a knowledge based TBM tunnel segment lining design program
Jeong, Yong-Jun ; Yoo, Chung-Sik ;
Journal of Korean Tunnelling and Underground Space Association, volume 16, issue 3, 2014, Pages 321~339
DOI : 10.9711/KTAJ.2014.16.3.321
This paper concerns the development of a knowledge-based tunnel design system within the framework of artifical neural networks(ANNs). The system is aimed at expediting a routine tunnel design works such as computation of segment lining body forces and stability analysis of selected cross section. A number of sub-modules for computation of segment lining body forces and stability analysis were developed and implemented to the system. It is shown that the ANNs trained with the results of 3D numerical analyses can be generalized with a reasonable accuracy, and that the ANN based tunnel design concept is a robust tool for tunnel design optimization. The details of the system architecture and the ANNs development are discussed in this paper.
Limit states design for tunnels: related researches and present state of application
Kim, Hong-Moon ; Kim, Dong-Kook ; Lee, Sang-Duk ;
Journal of Korean Tunnelling and Underground Space Association, volume 16, issue 3, 2014, Pages 341~346
DOI : 10.9711/KTAJ.2014.16.3.341
The representative Limit State Design(LSD) codes, AASHTO LRFD and Eurocodes, are widely being applied when designing civil structures. However, these codes are only applying tunnel lining design and segments design for shield tunnels. Recently in Europe, the Eurocode 7 committee was trying to create a research group called EG12, but they reluctantly decided not to create EG12 since it could have an impact on some of the other Eurocodes(including Eerocodes 2 and 3). Still there is an effort to continue researching LSD for tunnelling. LSD method will become the norm for the field of civil structural design in the near future. Therefore, it is important to fully understand Eurocode7:Geotechnical design in connection with Eurocode 2 and Eurocode 3. In addition, it is essential to follow international research trends and also to research for application to tunnelling.