• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.117-127
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• 2010

Gound excavation is frequently executed in unsaturated soil conditions. In this paper, the effect of apparent cohesion in unsaturated soils on the ground behavior during underground excavation is studied. The VPPE (Volumetric Pressure Plate Extractor) test, the unsaturated triaxial test and the trap-door test were carried out to figure out how the behavior of soils varies depending on the variation of apparent cohesion. The test results show that the ground behavior is almost identical if the soil is either fully dry or fully saturated. However, if the soil is partially-saturated with the increase of water content, the ground behaves quite differently. In summary, the apparent cohesion in unsaturated soils plays key roles when excavating underground structures.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.685-690
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• 2023

It was analyzed that the volume of deep excavation works adjacent to existing underground structures is increasing according to the population growth and density of cities. Currently, many underground structures and tracks are damaged by external factors, and the cause is analyzed based on the measurement results in the tunnel, and measurements are being made for post-processing, not for prevention. The purpose of this study is to analyze the effect on the deformation of the structure due to the excavation work adjacent to the urban railway track in use. In addition, the safety of structures is evaluated through machine learning techniques for displacement of structures before damage and destruction of underground structures and tracks due to external factors. As a result of the analysis, it was analyzed that the model suitable for predicting the structure management standard value time in the analyzed dataset was a polynomial regression machine. Since it may be limited to the data applied in this study, future research is needed to increase the diversity of structural conditions and the amount of data.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.1
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• pp.75-80
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• 1997

In other to construct a subway, we have to consider the position of the subway and acquisition of a topography, profile-map, cross-map, underground facilities map. All information of underground is demanded accurate location in other to prevent of accident of underground in subway construction. We must think about water lines, sewer lines, electronic lines, telephone lines, all urban gas-line because these are needed construction the subway. And attributes of underground facilities recorded on topography are characteristics. length, width. number, position, and depth of the lines. We have to record these attributes because these are very important to design map on subway construction. If we develop GIS (Geographic Information System) to use the exact in-formation of the underground facilities, we can be management safely and prevent very dangerous accident as fast as possible. In this study, attribute informations are linked geographic informations about underground facilities and we can develop Underground Facilities Management System(UFMS) to analysis dangerous region through dangerous degreed and predict accident range with these informations.

• Journal of the Korean Geotechnical Society
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• v.37 no.5
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• pp.19-31
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• 2021

Groundwater level (GWL) causes the stress state within soil and affects the bearing capacity and the settlement of foundation. In this study, the analyses of influencing factors on GWL fluctuation were performed. From the results, river stage and moving average of precipitation were main influence components for urban near large river and rural areas, respectively. In addition, the prediction performance of GWL using artificial neural network (ANN) was conducted with respect to the influence components. As a result, the effect of main component was significant on the prediction performance of GWL.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.193-200
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• 2010

Due to the characteristic of culvert structure, the standard section of the culvert has been established and applied in field. However, this becomes a limitation in selecting a section design corresponding to various field conditions although it can improve the design and applicability of culvert structure. In order to overcome this limitation, we have developed the design and application technology of culvert structure corresponding to the field conditions that various shapes of culvert structure can be covered by assembly of precast segments. Because the structural characteristics of assembling-type waterway culvert structure, the thickness of structure and amount of reinforcing rods can vary according to the fixation or internal hinge status in the connection part of precast segments. This has a strong influence on the applicability and economic efficiency of culvert structure. Accordingly, in order to suggest a reasonable modeling technique of segment connection parts, this study has conducted the field experiment and numerical analysis. According to the results of field experiment and numerical analysis, the slab, wall and base slab with mortar splice sleeves have shown that the assembling-type of waterway culvert structure behaves like an integrated structure.

• Smart Media Journal
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• v.6 no.4
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• pp.88-93
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• 2017

The story of "A Tale of the Conquest over a Big Enemy from an Underground Nation" is a story that is distributed all over the world. This familiar narrative structure can be accepted without great objection even in places with different cultures. In case of storytelling with the elements extracted from the narrative according to the previous research, storytelling of the picture book was carried out using the element and structure of the narrative. One of the ways to content the story is called a re-writing. In this paper, we divided the components of picture book into literary subjects, plots, characters, and backgrounds. "A Tale of the Conquest over a Big Enemy from an Underground Nation" is analyzed in the same way. And presented storytelling of the picture book.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.181-186
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• 2005

Gravity method produces subsurface density distribution, which is direct information of soundness of basement. Therefore, microgravity is one of the most effective method for detections of limestone cavities, abandoned mine-shafts and other tunnels, The paper show the effectiveness of microgravity by three different field cases.

• Economic and Environmental Geology
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• v.20 no.1
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• pp.77-82
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• 1987

An analysis is made for the relative effectiveness in detecting a subsurface thin layer by four electromagnetic depth sounding systems; horizontal coplanar loops, perpendicular loops, vertical coplanar loops and vertical coaxial loops. The moduli and phases of mutual coupling ratios over a three-layered earth for the four systems are evaluated rapidly by the related convolution technique. Root mean square differences between the responses from the three-layered and the homogeneous earths are used to compare the relative effectiveness of the systems quantitatively. Comparing the all systems, it is found that the perpendicular loop system appears to be the most superior to the other systems.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.69-75
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• 2014

The priority of repair areas are chosen with the probability distribution of 0.3mm wide crack and carbonation induced corrosion. Data is analyzed and evaluated based on the 28 section of Precise Inspection for Safety and Diagnosis (PISD) in seoul. As the crack is distributed in log-normal, the carbonation and cover are in normal distribution. To have rational in repair sections among 503 sheets of underground structure, it is adopted the reliability index as well as the environment factors: strength, sonic speed, $CO_2$ concentration, corrosion, and content of chloride.

• Journal of Korean Society for Geospatial Information Science
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• v.5 no.1 s.9
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• pp.129-137
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• 1997

According to the functions of city are getting more complicate and diverse, recently the concerns about underground space have been risen, and many infra-structures for social activities are now constructed under the ground. To maintain these kind of infra-structures effectively, it is necessary for concerned workers to access easily to the existing drawings and design information. and to modify the design drawings immediately o the changes of design value. And in the field of construction, immediate structural analysis and generation of design drawings will help to promote manufacturing ability, the quality of products, and the effectiveness of maintenance of design materials effectively.