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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 22, Issue 6 - Dec 2012
Volume 22, Issue 5 - Oct 2012
Volume 22, Issue 4 - Aug 2012
Volume 22, Issue 3 - Jun 2012
Volume 22, Issue 2 - Apr 2012
Volume 22, Issue 1 - Feb 2012
Selecting the target year
A Case Study on the Ventilation and Heat Environment in a Underground Limestone Mine with Rampway
Kim, Doo-Young ; Lee, Seung-Ho ; Jeong, Kyu-Hong ; Lee, Chang-Woo ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 163~172
DOI : 10.7474/TUS.2012.22.3.163
As more diesel engines have been employed in underground limestone mines with large cross section, underground space environment is worsened by diesel exhausts and heat flow. This paper aims for the ultimate goal to optimize the work place environment through assuring the optimal required ventilation rate based on the analysis of the airflow, diesel exhaust gas concentrations and the effects of mechanization and deepening working face on temperature and humidity. Due to the insufficient capacity of the main exhaust fan and poor airway management, stagnant airflows were observed at various locations, while the flow direction was reversed instantly with passing diesel equipment and the flow reversal was also made by the seasonal variation of the outside surface weather. During the loading operation, CO concentration measurements were found to be frequently higher than the threshold limit of 50 ppm, and most of the
measurements during drilling and loading operations shows even more serious levels surpassing the permissible limit of 3 ppm. The actual ventilation quantity was considerably less than the required quantity estimated by the mine health and safety law, and this shortage problem was less serious in colder winter showing more effectiveness of the natural ventilation.
A Study on the Airflow Distribution in the Diagonal Ventilation Circuit for the Design of a High Level Radioactive Waste Repository
Hwang, In-Phil ; Choi, Heui-Joo ; Roh, Jang-Hoon ; Kim, Jin ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 173~180
DOI : 10.7474/TUS.2012.22.3.173
In this study, diagonal ventilation circuits that are advantageous in air flow direction control were studied. Based on the results of the study, it could be seen that air volumes in diagonal ventilation circuits could also be calculated using numerical formulas or programs if the air volumes and air flow directions to be infused into diagonal branches are determined in advance as with other serial/parallel circuits. To apply the results, design plans for high level radioactive waste repositories applied with diagonal ventilation circuits and parallel ventilation circuits. To compared the each design plans and obtain expected operation results, ventilation network simulations were conducted through the Ventsim program which is a ventilation networking program. Based on the results, in the case of diagonal repositories that was expected to cause great increases in resistance, fan pressure was 1570 pa, total flux was 84
, fan efficiency was 76.4%, fan power consumption was 181.2 kW and annual fan operating costs were 178,710,838 and thus maximum around 8% differences were shown in pressure and flux values and a difference of around 1.5% was shown in terms of operating costs.
Rockfall and Toppling Failure Simulation of Rock Slopes using 3-Dimensional Discontinuous Deformation Analysis
Hwang, Jae-Yun ; Ohnishi, Yuzo ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 181~187
DOI : 10.7474/TUS.2012.22.3.181
Many researches on disaster prevention using computer simulation methods can be performed to minimize the damage of property and to protect human life. Discontinuous deformation analysis (DDA) is a new computer simulation method to analyze the behavior of discontinuous rock masses. Since most rock slope problems are 3-dimensional in nature, 2-dimensional deformation analysis has limited application. In this study, the basic principles of 3-dimensional discontinuous deformation analysis are described. The newly developed 3-dimensional discontinuous deformation analysis method is proposed as the computer simulation method for discontinuous rock masses. Then, the failure behavior of rock slopes are simulated using 3-dimensional discontinuous deformation analysis. The simulation results are compared and examined with the failure behavior at the rock slopes. The results show the applicability of 3-dimensional discontinuous deformation analysis to analyze the deformation and failure mechanisms of rock slopes.
Numerical Study on the Thermal Stratification Behavior in Underground Rock Cavern for Thermal Energy Storage (TES)
Park, Do-Hyun ; Kim, Hyung-Mok ; Ryu, Dong-Woo ; Choi, Byung-Hee ; SunWoo, Choon ; Han, Kong-Chang ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 188~195
DOI : 10.7474/TUS.2012.22.3.188
Using a computational fluid dynamics (CFD) code, FLUENT, the present study investigated the thermal stratification behavior of Lyckebo storage in Sweden, which is the very first large-scale rock cavern for underground thermal energy storage. Heat transfer analysis was carried out for numerical cases with different temperatures of the surrounding rock mass in order to examine the effect of rock mass heating due to periodic storage and production of thermal energy on thermal stratification and heat loss. The change of thermal stratification with respect to time was quantitatively examined based on an index of the degree of stratification. The results of numerical simulation showed that in the early operational stage where the surrounding rock mass was less heated, the stratification of stored thermal energy was rapidly degraded over time, but the degradation and heat loss tended to reduce as the surrounding rock mass was heated during a long period of operation.
Generation of Roughness Using the Random Midpoint Displacement Method and Its Application to Quantification of Joint Roughness
Seo, Hyeon-Kyo ; Um, Jeong-Gi ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 196~204
DOI : 10.7474/TUS.2012.22.3.196
Quantification of roughness plays an important role in modeling strength deformability and fluid flow behaviors of rock joints. A procedure was suggested to simulate joint roughness, and characteristics of the roughness was investigated in this study. Stationary fractional Brownian profiles with known input values of the fractal parameter and other profile properties were generated based on random midpoint displacement method. Also, a procedure to simulate three dimensional roughness surface was suggested using the random midpoint displacement method. Selected statistical roughness parameters were calculated for the generated self-affine profiles to investigate the attribute of roughness. Obtained results show that statistical parameters applied in this study were able to consider correlation structure and amplitude of the profiles. However, effect of data density should be tackled to use statistical parameters for roughness quantification.
A Study on the Stability of Twin Tunnels in Anisotropic Rocks Using Scaled Model Tests
Kim, Jong-Woo ; Kim, Myeong-Kyun ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 205~213
DOI : 10.7474/TUS.2012.22.3.205
In this study, scaled model tests were performed to investigate the stability of twin tunnels constructed in anisotropic rocks with
inclined bedding planes under the condition of lateral pressure ratio, 2. Five types of test models which had respectively different pillar widths and shapes of tunnel sections were experimented, where both crack initiating pressures and deformation behaviors around tunnels were investigated. The models with shallower pillar width showed shear failure of pillar according to the existing bedding planes and they were cracked under lower pressure than the models with thicker pillar width. In order to find the effect of tunnel sectional shape on stability, the models with four centered arch section, circular section and semi-circular arch section were experimented. As results of the comparison of the crack initiating pressures and the deformation behaviors around tunnels, the semi-circular arched tunnel model was the most unstable whereas the circular tunnel model was the most stable among them. Furthermore, the results of FLAC analysis were qualitatively coincident with the experimental results.
Influence of Zero Reading on Predicting Crown Displacement of Tunnel
Kim, Kwang-Yeom ; Kim, Ho-Geun ; Seo, Youg-Seok ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 214~220
DOI : 10.7474/TUS.2012.22.3.214
Deformation behaviour of rock mass around an opening measured during tunnel excavation is very important in order to assess the stability of the tunnel. Unfortunately displacement measured only after the installation of displacement measuring device can be acquired, which results in inevitably excluding the pre-displacement occurred and accumulated before the displacement measuring devices are installed. So it is very important to consider the pre-displacement based on the elapsed time before zero reading after deformation behaviour started. In this study, the accuracy of total estimated displacement depending on the distance between face and measurement position is calculated by statistical non-linear fitting on measurable displacement data. Besides, the influence of the unavoidable measurement error is considered by using Monte-Carlo simulation. As a result, the faster the initial reading started and the smaller the measurement error is, the higher the accuracy of estimating total displacement is obtained.
Underwater Explosive Welding of Stainless Steel and Magnesium Alloy
Lee, Joon-Oh ; Kim, Young-Kook ; Cho, Sang-Ho ;
Tunnel and Underground Space, volume 22, issue 3, 2012, Pages 221~225
DOI : 10.7474/TUS.2012.22.3.221
Magnesium is one of the light weight materials, which can improve fuel economy and reduce emissions in automotive industry. Recently, magnesium alloys have gained considerable attention due to good mechanical properties. In this work, we have performed an explosive welding using the magnesium alloys (AZ31) and stainless steel (SUS 304). As a result, SUS304/AZ31 were successfully combined each other; however, a resolidified interlayer was observed at the point of welded layer. To reduce the resolidified interlayer, we have changed the thickness (0.5 mm and 1 mm) of stainless steel, distance (45 mm and 60 mm) between explosive and the center of materials and initial angle (
) of explosive. In the case of the thickness 0.5 mm and angle of
, the resolidfied interlayer was not observed due to the increase of distance from the explosive. To accurately estimate the resolidified interlayer, electron probe micro-analyzer (EPMA) method and hardness were used. For the EPMA analysis, mixed materials were confirmed at the resolidified interlayer, and the measurement exhibited the middle value compared with the AZ31 and SUS304.