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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Tunnel and Underground Space
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Journal DOI :
Korean Society for Rock Mechanics
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Volume & Issues
Volume 15, Issue 6 - Dec 2005
Volume 15, Issue 5 - Oct 2005
Volume 15, Issue 4 - Aug 2005
Volume 15, Issue 3 - Jun 2005
Volume 15, Issue 2 - Apr 2005
Volume 15, Issue 1 - Feb 2005
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Numerical Analysis for the Structural Behavior of Lattice Girder
Jeong Hyeon-Seok ; Kim Won-Beom ; Yang Hyung-Sik ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 243~249
Structural behavior of lattice girders of different loading conditions, loading patterns and shapes was analyzed by MIDAS, the finite element method. Optimal condition for lattice girders was represented.
Characteristics of the Progressive Brittle Failure around Circular Opening by Scaled Model Test and Discrete Element Analysis
Jeon Seok-Won ; Park Eui-Seob ; Bae Seong-Ho ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 250~263
Progressive and localized brittle failures around an excavated opening by the overstressed condition can act as a serious obstacle to ensure the stability and the economical efficiency of construction work. In this paper, the characteristics of the brittle failure around an circular opening with stress level was studied by the biaxial compressive test using sealed specimen and by the numerical simulation with
, one of the discrete element codes. The occurring pattern and shape of the brittle failure around a circular opening monitored during the biaxial loading were well coincided with those of the stress induced failures around the excavated openings observed in the brittle rock masses. The crack development stages with stress level were evaluated by the detailed analysis on the acoustic emission event properties. The microcrack development process around a circular opening was successfully visualized by the particle flow analysis. It indicated that the scaled test had a good feasibility in understanding the mechanism of the brittle failure around an opening with a high reliability.
Prediction of Rock Fragmentation and Design of Blasting Pattern based on 3-D Spatial Distribution of Rock Factor
Shim Hyun-Jin ; Seo Jong-Seok ; Ryu Dong-Woo ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 264~274
The optimum blasting pattern to excavate a quarry efficiently and economically can be determined based on the minimum production cost which is generally estimated according to rock fragmentation. Therefore it is a critical problem to predict fragment size distribution of blasted rocks over an entire quarry. By comparing various prediction models, it can be ascertained that the result obtained from Kuz-Ram model relatively coincides with that of field measurements. Kuz-Ram model uses the concept of rock factor to signify conditions of rock mass such as block size, rock jointing, strength and others. For the evaluation of total production cost, it is imperative to estimate 3-D spatial distribution of rock factor for the entire quarry. In this study, a sequential indicator simulation technique is adopted for estimation of spatial distribution of rock factor due to its higher reproducibility of spatial variability and distribution models than Kriging methods. Further, this can reduce the uncertainty of predictor using distribution information of sample data The entire quarry is classified into three types of rock mass and optimum blasting pattern is proposed for each type based on 3-D spatial distribution of rock factor. In addition, plane maps of rock factor distribution for each ground levels is provided to estimate production costs for each process and to make a plan for an optimum blasting pattern.
Prediction of Ground Condition and Evaluation of its Uncertainty by Simulated Annealing
Ryu Dong-Woo ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 275~287
At the planning and design stages of a development of underground space or tunneling project, the information regarding ground conditions is very important to enhance economical efficiency and overall safety In general, the information can be expressed using RMR or Q-system and with the geophysical exploration image. RMR or Q-system can provide direct information of rock mass in a local scale for the design scheme. Oppositely, the image of geophysical exploration can provide an exthaustive but indirect information. These two types of the information have inherent uncertainties from various sources and are given in different scales and with their own physical meanings. Recently, RMR has been estimated in unsampled areas based on given data using geostatistical methods like Kriging and conditional simulation. In this study, simulated annealing(SA) is applied to overcome the shortcomings of Kriging methods or conditional simulations just using a primary variable. Using this technique, RMR and the image of geophysical exploration can be integrated to construct the spatial distribution of RM and to evaluate its uncertainty. The SA method was applied to solve an optimization problem with constraints. We have suggested the practical procedure of the SA technique for the uncertainty evaluation of RMR and also demonstrated this technique through an application, where it was used to identify the spatial distribution of RMR and quantify the uncertainty. For a geotechnical application, the objective functions of SA are defined using statistical models of RMR and the correlations between RMR and the reference image. The applicability and validity of this application are examined and then the result of uncertainty evaluation can be used to optimize the tunnel layout.
Stress Distribution Under Line Load in Transversely Isotropic Rock Mass
Lee Youn-Kyou ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 288~295
Many mechanical defects originated from various geological causes make rock mass exhibit anisotropic characteristics. Understanding how the stress distribution occurs in anisotropic rock mass is, therefore, very important for the design of footings on rock and rock structures. In this study, the patterns of elastic stress distribution, developed by acting line load on the surface, in transversely isotropic was investigated. The influence of joint stiffness, joint spacing, and dip angle on the stress distribution was examined. By assuming the Mohr-Coulomb criterion as joint slip condition, the development of joint slip zone was also discussed.
A Safety Analysis of Electric Detonator for Stray Currents by Domestic Transmission Network System
Park Hyun-Sik ; Kim Young-Seok ; Kang Choo-Won ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 296~304
This study is to observe stray currents generated around the steel tower by domestic transmission network system and analysis stability of electric detonator. It is measured the stay current of each ten place at steel tower of 765 kV, 345 tV, 154 tV transmission line among domestic transmission network system. Stay currents measured a total of 40m at intervals of 4m toward a line direction and a line vertical direction centering around steel tower. Temperature of the surface, EC, water content also are measured. Although stay currents show the highest values, that is 12 percent of at 4m and less than 1 percent of 40m with Institute of Makers of Explosives(IME) regulations. It is shown correlation between stay currents and water content
temperature of the surface. Stay currents measured at line direction and line vertical direction were little different and the shape of diminution was also shown a similar aspect.
Application of New Edge-to-Edge Contact Algorithm to Discontinuous Deformation Analysis
Lee Chung-In ; Moon Young-Sam ; Choi Yong-Keun ; Ahn Tae-Young ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 305~315
DDA (Discontinuous Deformation Anlaysis) is one of the latest numerical analysis which has merits of both FEM and DEM. In this research a new edge-to-edge contact algorithm was applied on DDA. With adoption of new edge-to-edge contact state definition, sub-algorithm was improved about open-close iteration, contact state judge, contact detecting, and friction forces acting on joints. Newly applied DDA was verified based on two different cases. The DDA results show good agreement with numerically predicted one.
A Study on the Characteristics of Cooperating Charge considering Dominant Frequency
Kim Jong-In ; Kang Choo-Won ;
Tunnel and Underground Space, volume 15, issue 4, 2005, Pages 316~323
As a result of waveform analysis, the separation of waveform found that high frequency well accomplishes but low frequency doesn't accomplish that. The data which measured less than 60 Hz and more than 60 Hz was analysed to examine the relation between cooperating charge and frequency. The measured data of more than 70 Hz was also analysed to consider the characteristics of high frequency.