• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.32-42
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• 2007

Severe damage can occur around deposition holes due to complex interaction of thermo-hydro-mechanical (THM) loading during the long term operation of high level radioactive waste repository. Many candidate sites for repository are located in crystalline rock mass, therefore mechanism of damage follows the form of brittle fracture and failure. This paper briefly introduces major outcomes from 15 years international collaborative project, DECOVALEX, and presents major study results for current ongoing benchmark test study from DECOVALEX-THMC, to evaluate the effect of THM loading to rock mass in excavation damaged zone (EDZ) near deposition holes. Through benchmark test model by simplifying THM loading to boundary loading obtained numerical results are compared, and discrete fracture interaction after up to 1 million years operation is discussed.

• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.26-31
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• 2007

The 11 nuclear power plants have been taking charge of more than 40% of the total electrical power development in Korea. In addition to the existing nuclear power plants at Gori, Wolsung, Youngkwang, etc., the 12 nuclear power plants are expected to be newly established until 2006. So, the 23 nuclear power plants will produce the electric power as much as more than 50% of the national gross production. However the nuclear power plants are inevitably generating the detrimental atomic wastes. Therefore the disposal techniques for the nuclear wastes should be ensured considering a very high safety factor. According to the basic researches in KAERI, the underground disposal repositories are reported to be most favorable for Korea. The KBS-3 disposal system has been strongly suggested by KAERI and this system has a deep tunnel with several disposal boreholes in tunnel floor. The nuclear wastes, which are sealed tightly in a canister, will be disposed in these boreholes. Considering the disposal tunnel in a great depth, the in-situ stress regimes will affect severely the tunnel stability. Consequently the effect of the in-situ stresses on the disposal tunnel and the role of the in-situ stresses in tunnel stability analysis are examined by the numerical studies.

• Tunnel and Underground Space
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• v.33 no.5
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• pp.348-372
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• 2023

In relation to the high-level radioactive waste disposal project in deep fractured rock aquifer environments, it is essential to evaluate hydrogeological characteristics for evaluating the suitability of the site and operational stability. Such subsurface hydrogeological data is obtained through in-situ tests using boreholes excavated at the target site. The accuracy and reliability of the investigation results are directly related to the selection of appropriate test methods, the performance of the investigation system, standardization of the investigation procedure. In this report, we introduce the detailed procedures for the representative test method, the constant pressure injection test (CPIT), which is used to determine the key hydrogeological parameters of the subsurface fractured rock aquifer, namely hydraulic conductivity and storativity. This report further refines the standard test method suggested by the KSRM in 2022 and includes practical field application case conducted in volcanic rock aquifers where this investigation procedure has been applied.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.947-956
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• 2018

Subsea tunnel built in abyssal zone is exposed to environment under high water pressure caused by seawater and etc., and this high pressure from underground water may facilitate leaching. In particular, since underground water can be easily flown in during construction, this might cause many problems related to cutoff water. Therefore, in order to secure safety, it is necessary to apply grouting equipment and materials which are appropriate to construction environment. Accordingly, in this research, evaluation was made on the physical characteristics of grouting materials (strength, leaching and etc. depending on curing methods for each of used materials and condition) which can be applied during subsea tunnel construction. As a result of this research, stable strength increase was found in CA and CSA type, and it is determined that no decrease in their durability was found, so these can be used as stable materials for structures under influenced by seawater.

• Tunnel and Underground Space
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• v.24 no.3
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• pp.212-223
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• 2014

In this study, the stability analyses for metal mine roadways at a great depth were performed. In-situ stress measurements using hydrofracturing, numerous laboratory tests for rock cores and GSI & RMR classifications were conducted in order to find the physical properties of both intact rock and in-situ rock mass distributed in the studied metal mine. Through the scenario analysis and probabilistic assessment on the results of rock mass classification, the in-situ ground conditions of mine roadways were divided into the best, the average and the worst cases, respectively. The roadway stabilities corresponding to the respective conditions were assessed by way of the elasto-plastic analysis. In addition, the appropriate roadway shapes and the support patterns were examined through the numerical analyses considering the blast damaged zone around roadway. It was finally shown to be necessary to reduce the radius of roadway roof curvature and/or to install the crown reinforcement in order to enhance the stability of studied mine roadways.

• Tunnel and Underground Space
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• v.24 no.2
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• pp.166-175
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• 2014

In this study, the thermal environment in a large scale coal mine located in Taebaek, Gangwondo was assessed by a field survey. In order to estimate the thermal environment, various heat stress indices such as WBGT, HSI, ESI, KATA index and effective temperature were investigated. Correlation analysis was also conducted. It was found that the thermal environment in most workplace was high. In particular, the correlation coefficient between HSI reflected in physiological fatigue characteristic and the maximum sweat evaporation heat was -0.834. This shows that the correlation coefficient have the most influence on HSI index. The factor which has the most influence on the maximum sweat evaporation heat is velocity of air. The thermal environment of high-depth coal mines is likely to be improved by installing a structure that enables the maximum prevention of extended digging, air doors, or the leakage of the inflow of air in the first shaft.

• Journal of Korean Association for Spatial Structures
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• v.11 no.2
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• pp.139-149
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• 2011

A cable structures have the advantage that cover a large space without column but it is very sensitive to deal with shape control because of its flexibility. Especially, location of control member and needed elongation of member are important things. Therefore, the purpose of this paper is studied on displacement control technique for pre-stressed cable structures by force method considering order of control. The layout of this paper is as follows. Firstly, in section 2, the control technique by force method for cable structures is given. Secondly, section 3 briefly introduces simple cable net in order to apply control technique considering ordering of actuator. Finally, more complex example for effective member and the conclusion are in section 4 and 5, respectively.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.184-191
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• 2009

Ideas regarding acting among new theater groups In the 1960s can be summarized in two major trends. The first trend was characterized with the pursuit of identity in a play. The second trend was characterized with the pursuit of creating a play that strongly and passionately explores internal human reality. In their pursuit of the goal of the second trend, they shockingly and strongly destroyed anything by rising in revolt against the existing spatial language. They believed that acting beyond acting as pursued by Stanislavski is not to implant a new type of human, but to develop the self hidden within the actor or to remove the actor's mask. Based on such recognition, the first thing that actors have to do is to remove or break free from the shell or skin that surrounds them. Accordingly, they sought a method that helped them act while taking off their shell or mask during acting and finally got the answer from "improvisation." One thing with improvisation is its way of stimulating the unconscious world of the actors in order to allow them to strongly express the hidden instinctive emotion from deep within them.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.437-442
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• 2016

The marriage between music and film, both temporal art forms, demands that the inherent aspects of note in each medium are brought into correspondence within a dramatic context. In film-making, the most crucial and difficult problem a film composer faces is finding the music that seems absolutely right for the film and its characters, sequences and dramatic lines. When writing a film score, composers become musical dramatists; some have a special instinct that enables them to find the right kind of melodic line, orchestral texture, rhythmic device and musical style to bring out what they intuitively recognize as the essential aspect of the drama. In this study, several examples are cited - Alex North, Hugo Friedhofer, Bernard Herrmann and David Raksin - that underline this kinetic function of music in film. Effort is made to uncover as many possibilities as possible, so as to arrive at a better understanding of how the two media interrelate for the purpose of emphasizing the dramatic lines.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.215-225
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• 2015

We performed injection tests in a deep-seated confined aquifer to assess the potential of artificial recharge as a means of preventing saltwater contamination, thereby securing groundwater resources for the Nakdong Delta area of Busan City, Korea. The study area comprises a confined aquifer, in which a 10-21-m-thick clay layer overlies 31.5-36.5 m of sand and a 2.8-11-m-thick layer of gravel. EC logging of five monitoring wells yielded a value of 7-44 mS/cm, with the transition between saline and fresh water occurring at a depth of 15-38 m. Above 5 m depth, water temperature is 10-15.5℃, whereas between 5 and 50 m depth the temperature is 15.5-17℃. Approximately 950 m³ of fresh water was injected into the OW-5 injection well at a rate of 370 m³/day for 62 hours, after which the fresh water zone was detected by a CTD Diver installed at a depth of 40 m. The persistence of the fresh water zone was determined via EC and temperature logging at 24 hours after injection, and again 21 days after injection. We observed a second fresh water zone in the OW-2 well, where the first injection test was performed more than 20 days before the second injection test. The contact between fresh and saline water in the injection well is represented by a sharp boundary rather than a transitional boundary. We conclude that the injected fresh water occupied a specific space and served to maintain the original water quality throughout the observation period. Moreover, we suggest that artificial recharge via long-term injection could help secure a new alternative water resource in this saline coastal aquifer.