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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Tunnel and Underground Space
Journal Basic Information
Journal DOI :
Korean Society for Rock Mechanics
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Volume & Issues
Volume 20, Issue 6 - Dec 2010
Volume 20, Issue 5 - Oct 2010
Volume 20, Issue 4 - Aug 2010
Volume 20, Issue 3 - Jun 2010
Volume 20, Issue 2 - Apr 2010
Volume 20, Issue 1 - Feb 2010
Selecting the target year
An Analysis of Stability on Rock Slope by Changing Water Level
Jang, Hyong-Doo ; Yang, Hyung-Sik ;
Tunnel and Underground Space, volume 20, issue 1, 2010, Pages 7~14
A quarry with 105 m height large cut slope was analyzed. Beside RMR and SMR methods, FLAC2D were adopted to analyze slope stability. As a result, slope of andesite had a possibility of failure. Wet slope showed low safety factor. Soil nailing was recommended to solve it. Since safety factor of slope largely depend on underground level, investigation for it seemed necessary.
Numerical Analysis on Morphologic Characteristics of Rock Slope for Reducing Rockfall Risk
Ji, Hyun-Woo ; Choi, Sung-O. ;
Tunnel and Underground Space, volume 20, issue 1, 2010, Pages 15~27
Geo-hazard shows a rapid increasing tendency with establishment of frequent great slopes in various construction sites, especially in the unfavorable topographic condition in which about 70% of the surface is covered by the mountainous area. An repeatedly taking place on the heavy rain season is accompanied by a large scale of rockfall, and causes great damage to an individual as well as a property. Even though lots of field studies and fundamental studies have been performed to reduce this hazard, however, an essential study on the mechanism of the rockfall should be limited to the conventional studies on the slope reinforcement and/or the rockfall risk analysis. In this study, the mechanism of rockfall depending on the morphologic characteristics of slope has been simulated numerically with the PFC2D, one of the discrete element programs. For analyzing its mechanism, the input parameters relating to the slope such as surface condition, gradient, number of benches, bench gradient, and the ratio of bench width to rockfall size were taken into consideration.
A Study on the Numerical Analysis of A NATM Tunnel with Consideration of Construction Procedure and Field Measurement
Park, Choon-Sik ; Kang, Man-Ho ;
Tunnel and Underground Space, volume 20, issue 1, 2010, Pages 28~38
In order to investigate the tendency of general displacements and behaviors with respect to each construction process as well as the applicability of numerical analysis schemes, this research has focused on not only analyzing a variety of field observations made in a NATM tunnel, such as displacement of top and side, stress of shotcrete and axial strength of rock bolt, but also carrying out a series of numerical analyses. It was established from the investigation that the 2-dimensional continuum numerical analysis was the one which could more accurately predict displacement of crown and side in the area of one step excavation (patten, P1-P3), while the 2-dimensional discontinuum analysis was the most suitable scheme to study that of two step excavation (patten, P4-P6). In addition, the 2-dimensional continuum analysis enabled to appropriately predict the axial strength of rock bolt and stress of shotcrete in all the area of the tunnel. Finally, it has been possible to conclude from the study that the 3-dimensional continuum analysis should be applied to inspect the behavior and tendency with respect to each stage of the construction as well as in the case of joints, such as large turnouts where relaxation loads in both of horizontal and vertical direction are piled up.
Reliability Assessment of Tunnel Support Systems Using a Probability-Based Method
Park, Do-Hyun ; Park, Eui-Seob ; Song, Won-Kyong ; Ryu, Dong-Woo ;
Tunnel and Underground Space, volume 20, issue 1, 2010, Pages 39~48
The present study developed a program which can assess the reliability of tunnel support systems based on a probability-based method. The developed program uses FLAC2D as a solver, and can automatically execute all the processes, associated with numerical and probabilistic analysis. Since a numerical analysis, which models the ground, requires a significant calculation time, it is actually impossible to apply simulation-based methods to probabilistic assessment on the reliability of tunnel support systems. Therefore, the present study used a point estimate method, which is efficient for probabilistic analysis since the method can significantly reduce the number of samples when compared with the simulation-based method. The developed program was applied to a tunnel project, and the results were compared with those through a deterministic approach. From the comparison, it was identified that a probabilistic approach can quantitatively assess the reliability of tunnel support systems based on probability of failure and can be used as a tool for decision making in tunnel support designs.
Elasto-plastic Analysis of Circular Tunnel with Consideration of Strain-softening of GSI Index
Lee, Youn-Kyou ; Park, Kyung-Soon ;
Tunnel and Underground Space, volume 20, issue 1, 2010, Pages 49~57
For the elasto-plastic analysis of a circular tunnel driven in a strain-softening rock mass subjected to a hydrostatic in-situ stress condition, this study suggests a convenient elasto-plastic analysis scheme which takes the strain-softening of GSI index into account and demonstrates its potential as a numerical tool in designing a circular tunnel. The suggested numerical scheme was developed by modifying the previous elasto-plastic procedure proposed by Lee & Pietruszczak(2008). With the assumption that GSI index of rock mass adjacent to the tunnel surface may be degraded due to the damage caused by the blasting and excavation, the concept of the strain-softening of GSI index was invoked. The concept provides a useful tool considering the strain-softening of the strength parameters appearing in the generalized Hoek-Brown criterion because these parameters can be evaluated empirically by use of GSI. In order to check the validity of the proposed scheme, the elasto-plastic analyses for circular tunnels were performed in various analysis conditions and the results were discussed.
A Study on Field Change Case of Tunnel Concrete Lining Designs Using GLI(Ground Lining Interaction) Model
Chang, Seok-Bue ; Lee, Soo-Yul ; Suh, Young-Ho ; Yun, Ki-Hang ; Park, Yeon-Jun ; Kim, Su-Man ;
Tunnel and Underground Space, volume 20, issue 1, 2010, Pages 58~64
GLI model was verified to consider the interaction between a ground and a tunnel lining and to rationally reduce the ground load acting on the secondary lining(concrete lining) of a tunnel. In this study, the economy and the construction condition of tunnel concrete linings designed by a conventional frame model at Lot O of OO line were highly enhanced through a field design change using GLI model. For a few safe considerations, not only about 50% saving of reinforcing steel could reduce the material cost but also the wide space between bars could make it easy to pour concrete mix without voids. There was large saving effect of reinforcing steel for poor ground conditions because Terzaghi's load used in the conventional frame model produces too much high loads for those conditions.
Study on the Crack Generation Patterns with Change in the Geometry of Notches and Charge Conditions
Park, Seung-Hwan ; Cho, Sang-Ho ; Kim, Seung-Kon ; Kim, Kwang-Yeom ; Kim, Dong-Gyou ;
Tunnel and Underground Space, volume 20, issue 1, 2010, Pages 65~72
Crack-controlled blasting method which utilizes notched charge hole has been proposed in order to achieve smooth fracture plane and minimize the excavation damage zone. In this study, the blast models, which have a notched charge hole, were analyzed using dynamic fracture process analysis software to investigate the effect of the geometry of a notched charge hole and decoupling indexes of the charge hole on crack growth control in blasting. As a result, crack extension increased and damage crack decreased with the notch length. Ultimately, stress increment factors and resultant fracture patterns with different notch length and width were analyzed in order to examine the effect factors on the crack growth controlling in rock blasts using a notched charge hole.