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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 14, Issue 6 - Nov 2012
Volume 14, Issue 5 - Sep 2012
Volume 14, Issue 4 - Jul 2012
Volume 14, Issue 3 - May 2012
Volume 14, Issue 2 - Mar 2012
Volume 14, Issue 1 - Jan 2012
Selecting the target year
A comparative study on methods for shield tunnel segment lining sectional forces
Yoo, Chung-Sik ; Jeon, Hun-Min ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 159~181
DOI : 10.9711/KTAJ.2012.14.3.159
The segment lining which consists of segments and joints are main component of shield tunnel. There are a number of methods that are being used in design which compute the sectional forces of a ring of segment lining. The traditional design methods which do not consider the effect of joints have been commonly used for design procedure without a specific verification of structural analysis. This paper presents the result of a comparative study for analytical and numerical models of the shield tunnel segment lining. For the traditional methods, the elastic equation method and the Duddeck & Erdmann method were considered. The ring-beam and the continuum analysis model were also considered as the numerical model.
The effect of grid number and the location and size of the fire source on the critical velocity in a road tunnel fire
Lee, Seung-Chul ; Kim, Sang-Il ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 183~195
DOI : 10.9711/KTAJ.2012.14.3.183
This study conducted comparative analysis to estimate critical velocity in tunnel fire under variation of grid number and the location and size of the fire source using three-dimensional computational fluid dynamics. In the target tunnel, by one-dimensional way, the calculated critical velocity in the tunnel, 2.22 m/s was estimated, if appling hydraulic diameter, instead of the tunnel height. According to six numerical analysis, each grid number has different position, temperature, and CO concentration of back-layering. In the case of the subject, the case 1 with 0.84 million grid was found to be the most ideal. According to the location and size of the fire source, after three cases for three-dimensional numerical analysis was performed, it is resulted that the location and size of the fire source affect the critical velocity, because air velocity distribution, temperature distribution and CO concentration distribution showed different each case. This is due to the difference of heat exchange area and locations. Therefore, it is necessary to decide appropriate grid number, and the location and size of the fire source for processing techniques through comparison with actual experiment results and three-dimensional analysis.
Characterization of the deformation of a disc cutter in linear rock cutting test
Chang, Soo-Ho ; Choi, Soon-Wook ; Park, Young-Taek ; Lee, Gyu-Phil ; Bae, Gyu-Jin ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 197~213
DOI : 10.9711/KTAJ.2012.14.3.197
Disc cutter is a key cutting tool for rock excavation by TBMs. This study aimed to characterize the deformation of a cutter ring by strain measurement as well as infrared thermal camera measurement during a series of linear cutting tests for a hard rock. The strain measurement results indicated that the cutter ring clearly showed a linear elastic behavior. The data obtained from the infrared thermal camera measurement demonstrated that the maximum temperature increase in the cutter ring was below
. The deformation and temperature increase of the cutter ring during rock cutting were insignificant in a given cutting test condition of this study.
An experimental study on mechanical behavior of shield segment with high-strength concrete and high-tension rebar
Lee, Gyu-Phil ; Park, Young-Taek ; Choi, Soon-Wook ; Bae, Gyu-Jin ; Chang, Soo-Ho ; Kang, Tae-Sung ; Lee, Jin-Seop ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 215~230
DOI : 10.9711/KTAJ.2012.14.3.215
An experimental research on the possibility of using high-strength concrete with the design strength of 60 MPa and high-tension rebar with the yielding strength of 600 MPa instead of conventional reinforced concrete segment to reduce its production cost was performed. Full-scale bending tests on both conventional and high-strength reinforced concrete segments were carried out to compare their mechanical and structural behaviors of the segments under flexural action. From the experiments, it was shown that the failure load of high-strength reinforced concrete segment was approximately 30% higher than that of the conventional segment even though reinforcements in high-strength segment were reduced by 26%. The test result showed that the bearing capacity of high-strength segment highly increased by high-strength concrete and high-tension rebar. It also verified the high possibility of high-strength reinforced concrete segment as a technical alternative to reduce the production cost of segments in a shield tunnel.
Behavior of tunnel adjacent to weak zone by using scaled model test
Lee, Dong-Seok ; Joen, Jae-Hyun ; Park, Jong-Deok ; Lee, Seok-Won ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 231~246
DOI : 10.9711/KTAJ.2012.14.3.231
Recently, the construction of tunnel frequently involves neighboring weak ground conditions. In this case, the stabilized ground could be relaxed by the excavation of tunnel. This will create issues in terms of stability of tunnel. Major factors determining the stability of tunnel can be the direction (angle) of weak zone, the distance between tunnel and boundary of weak zone and so on. In this study, by quantifying the displacement and crack propagation during the excavation of tunnel constructed neighboring weak zone, the influence of the direction of weak zone and the distance between tunnel and boundary of weak zone on the mechanical behavior of tunnel is investigated. A series of experimental scaled model tests by changing the direction of weak zone and the distance between tunnel and boundary of weak zone, are performed and analyzed under the condition of homogeneous material. The results show that as the angle between ground surface and boundary of weak zone moves from horizontal to perpendicular plane, displacement near tunnel increases. An increased distance between tunnel and boundary of weak zone induces displacements near tunnel to decrease and stabilizes beyond a certain level of distance. These findings verify and extend the earlier studies quantitatively. Finally, an appropriate distance between tunnel and boundary of weak zone according to the angle of weak zone is justified. This fundamental insight provides the basis for a more rational design of tunnel neighboring weak ground conditions.
Evaluation of tensile properties of SFRC for TBM tunnel segment
Moon, Do-Young ; Chang, Soo-Ho ; Bae, Gyu-Jin ; Lee, Gyu-Pil ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 247~260
DOI : 10.9711/KTAJ.2012.14.3.247
In order to reduce the amount of steel reinforcements in TBM tunnel segments, the use of Steel Fiber Reinforced Concrete(SFRC) is being tried. The steel fibers with higher aspect ratio than that used in tunnel shotcrete are preferred to compensate the deficiency in tensile strength of the segments. In this study, the tensile properties of SFRC with aspect ratio of steel fibers equal to 80 were evaluated through flexural test and Double Punch Test. In the results of flexural test, flexural strengths of the SFRC were increased about 30%~150% thanks to bond of steel fibers used to concrete and could be properly predicted by the equation proposed by Oh(2008). There was a great difference in the estimated direct tensile strengths of the SFRC by the equations presented in ACI and RILEM. It was found that the Double Punch Test could be suitable methodology to estimate the direct tensile strength presented in RILEM of the SFRC.
Infiltration behaviour of the slurry into tunnel face during slurry shield tunnelling in sandy soil
Roh, Byoung-Kuk ; Koh, Sung-Yil ; Choo, Seok-Yeon ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 261~275
DOI : 10.9711/KTAJ.2012.14.3.261
This paper presents numerical analysis of the mud cake infiltration behaviour which is influenced tunnel face stability during excavation by slurry shield TBM. This analysis method can make useful data to select proper shield TBM type and to set up the construction plan. But effective analysis did not proposed until now. In this paper, we carried out numerical analysis using by
fluid coupling simulation which is suitable for sandy soil modelling. As a analysis result, we checked that the slurry infiltration behaviour varied with soil permeability and slurry characteristic(specific weight, viscosity etc). This analysis method is helpful safety excavation through anticipating the proper slurry viscosity at the design stage and verifying the slurry quality at initial excavation stage.
A fundamental study on drag force of shield TBM cutter bit by scaled model test
Kim, Sang-Hwan ; Jang, In-Suk ; Kim, Ji-Tae ;
Journal of Korean Tunnelling and Underground Space Association, volume 14, issue 3, 2012, Pages 277~292
DOI : 10.9711/KTAJ.2012.14.3.277
This paper presents the fundamental study on drag force of shield TBM cutter bit by scaled model test. Several theoretical analyses of the drag force of cutter bit have been studied. However, there are still some difference between the theoretical approaches and actual drag bit capacity. In order to study the drag forces of shield TBM cutter bit, the scaled model tests are carried out and analyzed. The results obtained from scaled model tests are compared with the existing theoretical equations. It is highly expected that the results of this study will be very essentially useful to design and develope the TBM cutterhead.