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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)
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Volume & Issues
Volume 11, Issue 4 - Dec 2009
Volume 11, Issue 3 - Sep 2009
Volume 11, Issue 2 - Jun 2009
Volume 11, Issue 1 - Mar 2009
Selecting the target year
Model test on concrete placement method of tunnel lining due to tunnel size
Kim, Sang-Hwan ; Shin, Beom-Seok ; Park, Inn-Joon ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 213~221
This paper presents the concrete placement method of tunnel lining to improve the concrete lining quality such as cavities, cracks of the concrete lining. In order to perform this study, the occurred cracks initially in the concrete lining are reviewed and analyzed. From the review, the improvement methods to minimize the defects of concrete lining are suggested. To confirm the efficiency of new concrete placement approaches and the scale of tunnel section, two types of the scaled model tests are carried out and analyzed in model scales of 1/20 and 1/7. The 1/20 scaled model tests are carried out using the existing experimental rigs. The 1/7 scaled model tests are carried out in new test rigs developed in this study. The concrete placement rates obtained from the experimental results are analyzed and compared with themselves. In the existing concrete placement method, 1/20 scale model test than 1/7 scale model test have increased concrete placement rates but It is clearly found that two kinds of experimental studies show the similar results in improvement methods and good agreement with new concrete placing approach.
The dynamic characteristics of upper hot gas layer and smoke propagation along with tunnel slope in case of fire
Rie, Dong-Ho ; Kim, Ha-Young ; Moon, Sung-Woong ; Yoo, Ji-Oh ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 223~228
The aim of this research is to analyse the dynamic characteristics of the hot upper smoke layer in case of fire in a tunnel. In order to get the result, computer simulation technique has been used. The fire scenarios were set on the basis of standard cross section of national and express highways through NIST's FDS. As the area of a tunnel increased, the influence of the wind velocity decreased. Furthermore, the influence of the slope of a road was reduced as the wind velocity increased. On the other hand, as the wind velocity increased, the influence of the slope of a road decreased. This phenomena is believed to be caused by the cooling effect of wind which is over 1 m/s in speed, hence, reducing the influence of the effect of slope.
Numerical analysis of tunnelling-induced ground movements
Son, Moo-Rak ; Yun, Jong-Cheol ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 229~242
Numerical analysis has been performed to estimate maximum settlement, maximum horizontal displacement and total settlement volume at the ground surface due to tunnel excavation varying ground condition, tunnel depth and diameter, and construction condition (volume loss at excavation face). The maximum surface settlement from the numerical analysis has been compared with the maximum settlement at tunnel crown considering ground condition, tunnel depth and diameter, and construction condition, and it has been also compared with the maximum horizontal displacement. In addition, the volume loss (
) at tunnel excavation face has been compared with the total surface settlement volume (
) with the variation of ground condition, tunnel depth, and tunnel diameter. The results from the numerical analysis have been compared with field measurements to confirm the applicability and validity of the results and by this comparison it is believed that the numerical results in this study can be utilized practically in analyzing the ground movements due to tunnel excavation.
Hydraulic and structural interaction of a double-lined tunnel lining due to drainhole blockings
Shin, Jong-Ho ; Nam, Taek-Soo ; Chae, Sung-Eun ; Yoon, Jae-Ung ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 243~254
Tunnel problems relate to pore water pressure generally occur due to the restriction of groundwater flow into the tunnel which is generally caused by the deterioration of drainage systems. Previous studies have identified the problem as combined mechanical and hydraulic interaction occasions. In this study, detrimental effects of pore water pressure on the lining were investigated using the finite element method considering deterioration of the drainage system. Particularly, double-lined linings with drain-holes are considered. Deterioration of drainage system is represented as blockages of drain-holes. It is identified that the secondary lining ran be influenced by the deterioration of drainage system. It is shown that a tunnel with all drain-holes blocked moved upward, and unbalanced drain-hole blocking may result in torsional behavior of the tunnel which causes significant damages to the secondary linings.
Numerical investigation on 3D behavior of 2-Arch tunnel
Yoo, Chung-Sik ; Kim, Joo-Mi ; Kim, Hee-Chul ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 255~264
This paper concerns the behavior of 2-Arch tunnel constructed under various conditions. A 2-Arch tunnel section adopted in a subway tunnel construction site is considered in this study. A calibrated 3D finite element model was adopted to conduct parametric studies on a variety of construction scenarios including lagged distance between left and right tunnels, overburden, and geological condition. The results of analyses were examined in terms of crown settlement, shotcrete lining stress, and load on center column in relation to the lagged distance, cover depth, and the ground condition. The results indicate that the shotcrete lining stress and the center pillar load are more influenced by the second tunnel excavation than the tunnel deformation. Also shown is that a greater lagged distance is required to minimize the interaction between two tunnels when the ground condition becomes weaker. Fundamental mechanisms of 2-arch tunnel were also discussed based on the results.
Mechanical behaviour of rib-reinforced precast tunnel liner according to variable rib-reinforcement shapes
Lee, Gyu-Phil ; Lee, Seong-Won ; Hwang, Jae-Hong ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 265~275
Due to the limitation of construction efficiency and structural safety, the application of the high covering and wide width tunnels was limited prior to the introduction of precast rut and cover tunnels. Therefore, a cut and cover tunnel structure with rib reinforcement is proposed to mechanically improve the safety on condition of high covering and wide width tunnel. Therefore, a technical problem that can provide a response similar to the actual filling conditions is analyzed by the finite element analyses, moreover, the mechanical behaviour of developed rib-reinforced precast tunnel liner through a large-sized model test will be investigated. The ultimate load of the developed rib-reinforced precast tunnel liner shows a 3% reduction compared to existing rib-reinforced precast tunnel liner, especially, the section of rib-reinforcement decreased to 55% compared to it of existing. Therefore, the stability of tunnel structure can be significantly improved through the developed rib-reinforced precast segment.
Development of inorganic thixotropic-grout for backfilling of shield TBM tail voids and its compatibility
Kim, Dae-Hyun ; Jung, Du-Hwoe ; Jeong, Gyeong-Hwan ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 277~286
A suitability of a thixotropic grout developed in this study has been examined through laboratory tests on strength, segregation, and viscosity. The thixotropic grout is a mixture of two types of liquid components. The A-liquid component consists of cement, water, and MG-A and the B-liquid component consists of scarlet, water, and MG-B. Unconfined compressive strength of specimens prepared with a prefer mix-proportion satisfied a design criteria for the backfilling of tail voids. A material segregation phenomenon under water condition was not observed in the thixotropic grout whereas it was observed in the existing silica-type grout. In addition, viscosity tests have been rallied out on the thixotropic grout to verify the capability of a long-distance delivery in the field. Both the A-liquid component and the B-liquid component maintained a viscosity of below 2,000 cP for 120 minutes. This experimental result confirms that two liquid components guarantees a long-distance delivery in tile field application.
Seismic analysis and dynamic behavior characterization of rib-reinforced pre-cast tunnels
Song, Ki-Il ; Jung, Sung-Hoon ; Cho, Gye-Chun ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 287~301
The novel cut-and-cover tunnel construction method using rib-reinforced pre-cast arch segments has been recently developed and applied for practice to secure a structural stability of high covering and wide width section tunnels. Cut-and-cover tunnels are usually damaged by the seismic behavior of backfill grounds in case of a low covering condition. Seismic analyses are performed in this study to characterize the dynamic behavior of rib-reinforced pre-cast arch cut-and-cover tunnels. Seismic analyzes for 2 lane cast-in-place and rib-reinforced pre-cast arch cut-and-cover tunnels are carried out by using the commercial FDM program (FLAC2D) considering various field conditions such as the covering height embankment slope and excavation slope. It can be concluded that the amplification of seismic wave is reduced due to an increase in the structural stiffness induced by rib-reinforcement. The results show that the rib-reinforced pre-cast arch cut-and-cover tunnels are more effective against the seismic loading, compared to the cast-in-place cut-and-cover tunnels.
A study on the asperity degradation of rock joint surfaces using rock-like material specimens
Hong, Eun-Soo ; Kwon, Tae-Hyuk ; Cho, Gye-Chun ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 303~314
Image analyses for sheared joint specimens are performed to study asperity degradation characteristics with respect to the roughness mobilization of rock joints. Four different types of joint specimens, which are made of high-strength gypsum materials, are prepared by replicating the three-dimensional roughness of rock joints. About twenty jointed rock shear tests are performed at various normal stress levels. The characteristic and scale of asperity degradation on the sheared joint specimens are analyzed using the digital image analysis technique. The results show that the asperity degradation characteristic mainly depends on the normal stress level and can be defined by asperity failure and wear. The asperity degradation develops significantly around the peak shear displacement and the average amount of degraded asperities remains constant with further displacement because of new degradation of small scale asperities. The shear strength results using high-strength gypsum materials can not fully represent physical properties of each mineral particles of asperities on the natural rock joint surface. However the results of this quantitative estimation for the relationship between the peak shear displacement and the asperity degradation suggest that the characterization of asperity degradation provides an important insight into mechanical characteristics and shear models of rock joints.
Numerical analyses for mechanical behavior of cut-and-cover tunnel with precast arch type
Hwang, Jae-Hong ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 3, 2009, Pages 315~325
The thickness of the material can be thinned because arch cut-and-cover tunnel has the support mechanism by the axial force, and the ground reaction force due moderate deformation can be expected thereby making it be dynamically advantageous, therefore the arch cut-and-cover tunnel has become more widely used. An important characteristic of the arch cut-and-cover tunnel is that the thickness of the material can be thinned because precast arch type has the support mechanism by the axial force. However, there is a different stress state surrounding the structures between normally excavated tunnels and cut-and-cover tunnels, it should be considered at designing. Therefore, finite element method was carried out to examine the mechanical behavior of the precast arch cut-and-cover tunnel considering construction procedure.