• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.1
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• pp.15-25
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• 2022

This study was conducted to provide useful basic data for restoration and maintenance of the Changdeokgung Palace(昌德宮)'s inner palace area in the future by exploring the background of terraced flower beds installed in the front space of Seunghwaru(承華樓) and grasping the reality before and after terraced flower beds were installed. The main results of this study can be summarized as follows. First, in the early 1900s, the front space of Seunghwaru formed a relatively higher terrain than the Nakseonjae(樂善齋) area. In addition, along the topography of high north and low south, a yard surrounded by Haenggak(行閣) and a rectangular open space connected to the West Haenggak of Nakseonjae were created. In particular, the rectangular open space was a staircase-type slope in which rectangular stone columns were arranged at regular intervals. Second, the terraced flower beds of Seunghwaru originated from the renovation of the new building of Nakseonjae West Hanggak, which was implemented in the late 1920s. This is because in order to secure enough available land for construction and auxiliary space during the renovation of the new building, the terraced flower beds for topographic treatment was created along the cutting area after cutting off the original topography of the front space of Seunghwaru. Third, after the construction of the terraced flower beds, many deformation occurred in the topographic features of the front space of Seunghwaru. The front yard of Seunghwaru was relatively higher than the Nakseonjae area, but most of them were cut off and disappeared as the terraced flower beds were created. The staircase-type also disappeared after the construction of the new building and terraced flower beds. The stylobate and front fence of Seunghwaru were newly built along the alignment of terraced flower beds and the unique style of narrow gate and auxiliary stairs were also relocated to the new fence.

• Geotechnical Engineering
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• v.13 no.6
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• pp.165-180
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• 1997

The structure such as underground external walls of buildings, conduit and box culvert supports the surcharge loads (point, strip and line loads) . The vertical and horizontal stresses in a soil mass depend on the backfill width and wall friction, etc. The investigations described in this paper is designed to identify the magnitude and the distributions of the lateral and vertical pressure which is occurred by the narrowly backfilled soil in an open cut by the surcharge loads. For these purposes, model tests were performed for various width of backfill in a model test box by considering the wall friction using carbon rods. The results of test were compared with the theories of Weissenbach and VS Army Code and also with the results of the numerical analysis using finite difference method which introduces Mohr-Coulomb failure hypothesis.

• Geotechnical Engineering
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• v.1 no.2
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• pp.41-54
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• 1985

Generally, ground settlements and lateral displacements are accompanied by underground excavation associated with open-cut or tunnling. These ground movements cause a harmful influence upon nearby super.structures and sub-structures. Occasionally, the ground movements may pose serious problems as the function of the nearby structures may be disrupted. Therefore, prior to the subway construction in an urban area, it is necessary to identify the causes of ground settlements and estimating the extent St the magnitude of ground movements since any potential damage to the nearby structures such as gas lines, water mains, high buildings and cultural assets must be assessed. The research was performed mainly on ground movements such as surface settlements, lateral displacements, subsurface settlements and crown settlements to predict the maximum settlement and settlement zone, and to identify the causes of ground settlements in NATM sections of Busan subway. As a result, it was found that lateral distribution of settlements could be approximated reasonably by a Gaussian normal probability curve and longitudinal distribution of settlements by a cumulative Gaussian probability curve, and that the early closure of temporary invert was very important to minimize ground settlements.

• Explosives and Blasting
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• v.29 no.2
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• pp.13-31
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• 2011

Air deck charge blast methods have been applied to improve the fragmentation in open cut bench blastings for mining developments. However, during large scale bench blasting operations, there exist some problems such as boulder productions due to explosive charge concentration. Especially, in case of lime stone mining, when air deck method is applied, there has been unintentionally concentrated on charging because the inside holes are often broken by erosion and decomposition. In this study, compared with general blasting, air deck blasting has been focused in lime stone mining. In other to maximize its efficiency, inside hole was examined by endoscope in advance and deck charge using air tube was applied to the section in which concentration might be taken place. Blasting efficiency, fragmentation, charging reduction rate, and total working hours (from charging to blasting) were the main object for comparing, and as a result, air deck was more efficient then the general blasting in all aspects except total working hours.

• Explosives and Blasting
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• v.30 no.2
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• pp.21-28
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• 2012

Blasting methods are frequently used in case of forming slope artificially like slope cutting and open-cut method in the downtown area because of many economical and effective advantages. It is important that blasting work is carried out maintaining original strength of rock and not to damage rock face. And it is also considered that blasting method to decrease ground vibration is essential to the point of blast damages due to the ground vibration. In this study, to form a smooth plane of rock slope face, many trial blasts were carried out in this way that explosives were installed in detonating cord by equal interval in different charging method and stemming method. Using 4 blasting patterns in total 60 blast holes and 20 times of blasts were carried out. At the same time ground vibration measurements were carried out 15~102m away from the blast source, and total number of 310 data were obtained. Measured data for ground vibration velocity were analyzed so as to study blasting method to protect slope plane while decreasing blast vibration in an effective way.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.9-15
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• 2010

In this study, a non-open cut method using a round or square pipe which has been commonly employed in Korea was experimentally evaluated and the behavioral features resulting from the friction while the pipe is penetrated into the ground was identified through the scale model test. To that end, a test device was fabricated by type of penetration pipe, by which the surface displacement caused by surrounding friction resistance was monitored. To simulate the settlement and heaving by excavation stage, the test was conducted based on generalized friction condition and surface displacement and the result therof was compared and analyzed, considering the type of penetration pipe.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.25-37
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• 2019

The conventional representative underground cavity restoration methods, which are mainly open-cut methods, require high cost and long period of time for the restoration. Therefore, various trenchless restoration methods have been proposed to improve these disadvantages. The underground cavity restoration method using the expansive material proposed in this paper is one of the trenchless methods. This method fills the underground cavity with high quality backfill soils through the small hole(s) at asphalt layer and compacts backfill soils by insertion of the expansive material within the cavity. In this study, the restoration method using expansive material was constructed in acrylic chamber. The restoration efficiency of the method was analyzed by the fill ratio and degree of relative compaction according to the location and number of bore holes. As a result of the experiment, the restoration efficiency and the optimum construction location were found to be irrelevant.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.5
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• pp.100-106
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• 2004

$NO^3$-N removal was examined from July 2002 to December 2002 of a surface-flow constructed treatment wetland cell, which was a part of a treatment wetland system composed of four wetland cells and one distribution pond. The system was established on rice paddy near the Kohung Estuarine Lake located at the southern part of the Korean Peninsula. The lake and the paddy were formed by a salt marsh reclamation project. Effluent from a secondary-level treatment plant was funneled into the system. The investigated cell was created in June 2002. Its dimensions were 87 m in length and 14 m in width. It had an open water zone at its center, which was equivalent to 10 percent of its total area. Reeds(Phragmites australis) were transplanted from natural wetlands into the cell and their stems were cut at about 40 cm height from their bottom ends. Average 25 $m^3$/day of effluent from the plant was funneled into the cell by gravity flow and average 24.2$m^3$/day of its treated effluent was discharged into the Sinyang Stream flowing into the lake. Its water depth was maintained about 0.2 m and its hydraulic detention time averaged 5.2 days. The average height of the reed stems was 45.2 cm in July 2002 and 80.5 cm in September 2002. The number of stems averaged 40.3 stems/$m^2$ in July 2002 and 74.5 stems/$m^2$ in September 2002. The reeds were established initially well. $NO_3$-N loading rate of influent and effluent averaged 173.7 and $93.5mg/m2{\cdot}day$, respectively. Removal of $NO_3$-N averaged $80.2mg/m2{\cdot}day$ and its removal rate by mass was about 50 %. Considering the initial operation of the cell and the inclusion of the cold months of November and December in the analysis period, the $NO_3$-N removal rate was good.

• Fire Science and Engineering
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• v.18 no.4
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• pp.16-21
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• 2004

This paper has investigated influences of pollutants in air-breathing on the respirators and it by year of disused air respirators that fire fighter is using in domestic cutting done air respirators after collection observed state of cylinder material through instrumental analysis, and cut open pipe to confirm pollution degree of pipe from cylinder of air respirators to airline mask and confirm pollution availability. The metal surface inside the air respirators was corroded by moisture included in the compressed air. The material generated by corrosion is white powder of less then 100㎛, which is analyzed as aluminum hydroxide corroded by moisture. This aluminum hydroxide powder may get into the lung while one breathes in, and it is easy to be attached to the lung so it will cause a serious influences to human health. This study suggests that Korea should set out the standards for components and composition of breathing air as soon as possible.

• Journal of Sericultural and Entomological Science
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• v.28 no.2
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• pp.9-14
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• 1986

The rootability of hardwood cutting of mulberry (Morus alba L.) depending upon the kinds of cutting beds, soil of cutting beds, effect of growth regulator (Rootone-F), pretreatments of cutting scion, parts of branches were investigated, The results were as follows ; 1. Rootability was the highest in cutting after callus formed on sand bed, whereas null in the treatment of rice seedling hot bed. 2. Optimum cutting season was around March 26, showed 100% rootability in all treatments except wooden box filled with sand. 3. The order of rootability related with cutting part of branch was upper$^{\circ}C$), and cutting after formation of callus increased rootability, whereas cuttings left in open air for 5 days showed null rootability.