• KIEAE Journal
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• v.8 no.1
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• pp.87-92
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• 2008

Sheathing work used for excavation in a crowded downtown is generally a temporary strut method using H-piles and sheathing wall includes lagging, CIP, SCW or slurry wall. A temporary strut serving the support for sheathing wall acts to resist the earth pressure, but it shall be removed when installing the underground structure members. A traditional temporary strut might cause the stress imbalance of the sheathing wall when it is demolished, resulting in time extension and the risk of collapse. A traditional temporary strut method thus needs to be improved for schedule and cost reduction, risk mitigation and for preparation for potential civic complaint. A permanent strut method doesn't require installing and demolishing the temporary structure that will lead to reducing the time and cost and the structural risk during the demolition process. And given the girder, the part of the underground structure, serves the role of strut, it can secure the wider interval compared to the traditional method, which enables to secure the wider space for the convenience of excavation as well as enhance the constructability and efficient site management. The thesis was intended to study the composite girder designed to use the strut as permanent structure so as to reduce the excavation and floor height.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.145-146
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• 2022

The demand for a construction method capable of securing a safety environment and improving quality is increasing. There is a high risk of falling when working at a high place in an environment where it is difficult to secure visibility, such as an underground space, and there is a risk of falling if cement liquid waterproof materials are transferred to the top of the scaffold by manpower. In addition, when working on a high place in a poor environment, the quality uniformity of the upper part of the wall is deteriorated. In addition, as waterproof technicians gradually age and decrease, it is difficult to secure them, so it is urgent to prepare countermeasures against the shortage of waterproof technicians. Therefore, the purpose of this study is to develop cement liquid waterproof spouting construction equipment that can secure uniform quality of construction areas to prevent accidents and ensure safety of workers, improve work efficiency and quality due to improvement of work environment. The adhesion performance of the cement liquid waterproof material could be improved by about 20% in accordance with the use of the equipment.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.157-164
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• 2010

Recently, the number of shallow tunnel construction increases to improve the structural safety and environment-friendliness. In semi-cut-and-cover Method, ground is excavated to the crown arch level and arch slab is set to backfill before the excavation of lower face. In this study, laboratory model tests was performed to clarify the behavior of the arch slab constructed perpendicular to the slope. Results show that Arch slab is affected by perpendicular to the slope and bedrocks. Negative moment at the upper part of the arch slab at hillside and positive moment at the upper part at the other side are generated as perpendicular to the slope increases. Reaction load at the hillside support was larger than that at the other side.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.768-773
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• 2009

Measuring method being applied for off-shore works is performed by using data logger or manual measuring instrument with wiring the cable connected from the sensor up to the position where measuring is allowed.(upper part of embankment or marine structure) Measuring management by using existing measuring method may be acceptable on the condition that the ground deformation volume(vertical, horizontal) is generally minimal and the site condition is good. But loss of measuring instrument, sensor cable failure or cutting is taken place frequently due to significant change of ground behavior caused by an external force change(embankment, excavation) under very soft ground condition(N value below 0-4). In case of the marine works, in particular, loss rate of measuring instrument is highly represented due to the factors of working barge anchoring, constructional interference and natural disaster. In order to solve these problems, measuring management was performed with employing underground wireless system at the immersed tunnel site. Measuring data was obtained freely under the marine environment by using underground wireless communication and cable cutting potential by ground behavior could be reduced. Measuring cost savings and its installation convenience were maximized by way of off-shore tower installation or cabling and by minimizing constructional interference of off-shore working barge. This case of measuring management was accomplished successfully.

• Korean Journal of Environmental Agriculture
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• v.11 no.1
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• pp.26-40
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• 1992

Cheju Island formed by Quarternary volcanism provides highly permeable hydrogeological environment. To meet the increasing demand of water in the island, many groundwater wells have been developed. The environmental isotopes(oxygen-18, deuterium, tritium) and chemical analysis of water samples from the eastern part of the island were carried out to ascertain whether groundwater in the eastern part of the island was contaminated by sea water. The result of tritium analysis indicated fast infiltration of meteoric water into underground and rapid mixing process between rain water and groundwater. The results of oxygen-18 and deuterium analysis demonstrated that most of the wells in the eastern part of the island were influenced by sea water intrusion. Chemical analysis of water samples revealed that most groundwater in study area were classified into Na-Cl type and showed high chloride/bicarbonate ratios. Sea water intrusion in the northeastern part of the island has proceeded at least 3 km within the coastaline, and in the south eastern part about 700m.

• Journal of environmental and Sanitary engineering
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• v.17 no.1
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• pp.20-27
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• 2002

This study has researched the indoor air Pollution in the school classrooms. It focused on the school classrooms in which the students take part in many loaming activities for a long time, not focused on the offices or underground facilities that have occupied the interest so far. First, I investigated the origination sources of indoor air pollution which influences on our health, and researched the data on the consequences of it on the human body. Second, I measured the indoor air Pollution level of the classrooms in which the students take part in activities. I selected CO, $CO_2,{\;}SO_2,{\;}NO_2$and $PM_{10}$ as the research items. Each two schools were chosen in the elementary schools, middle schools and high schools as the ones for measurement. And I distinguished the boys' schools from the girls' schools in the middle and high schools. CO, $SO_2{\;}and{\;}NO_2$were comparatively low comparing with the recommendation of the Ministry of Environment. But, $CO_2{\;}and{\;}PM_{10}$ exceeded the standard concentration in most schools and there was a difference between boys'classrooms and girls'classrooms about them. Also, it was different by the number of members a classrooms. Third, I made a questionnaire on the on the indoor air pollution. The questionnaire showed that many students feel the indoor air pollution directly and they are under the influence of it.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1504-1506
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• 2004

The platform screen door(PSD) hasn't been installed yet within the manual operation system, that is, ATS & ATC Signal system. In other countries, it is mostly installed and operated within automatic operation system, that is, ATO. Especially, as a part of the environment friendly system installation, the installation of PSD shall be considered aggressively to improve the air quality in the underground area and to maintain the air-conditioning. Besides the number of suicides in the subway station gets increased these days causing safety hazard, so the installation of PSD is positively reviewed. To install PSD in the manual operation system, it is important to stop the train at the correct position. So we would like to suggest the technical system thereby.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.55-68
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• 2008

At present underground structures such as road tunnels, railway tunnels, underground petroleum storages and radioactive waste storages are being constructed in numerous places in Korea. For the construction of underground structrues, it should be accounted for natural factors (geology, hydrogeology, soil, vegetation, topography and drainage patterns) and human-social factors (land use, urbanization, population, culture and transportation). Especially, hydrogeology should be regarded as an important factor for evaluating the safety of underground structures and their impact to groundwater system around the structures. This study aimed to recognize hydrogeological characteristics of shallow formations in the area from Dongrae crossway to Seo-Dong where 45 boreholes were drilled for the construction of Line-3 subway in Busan Megacity. Slug tests for unsaturated and saturated zones were conducted on 30 boreholes in the study area. From the result of the slug tests, it was identified that average zonal hydraulic conductivity in the unsaturated zone was higher than that in the saturated zone. Besides, the slug test result in the saturated zones may reflect hydraulic properties of the upper most part of the saturated zones.

• 한국터널공학회:학술대회논문집
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• 2005.04a
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• pp.270-281
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• 2005

An especial attention for old tunnel safety is required on increasing of The various tunnel recently. Specially, the lining investigation method of the old tunnel will be able to presume condition of concrete lining indirectly. Because it is many restriction thought of environment and ground condition investigation method of tunnel lining rear. This study carried out section & convergence measurement of part which was deformed in tunnel lining. It had been observed for the change of tunnel behavior with a continuous measurement. It has been analyzed for a cause of tunnel deformation and inspected for the effect after a repair-reinforcement to tunnel compared with the effect before those by structure analysis. By establishing automatic measurement system after repair-reinforcement to tunnel, it would be accomplished to convergence measurement continually. As a result, it was observed that deflection and deformation of tunnel was convergent. but it should be followed to a continuous maintenance because of unstable ground condition, cause of inner tunnel, environment. The railroad tunnel which was executed a reinforcement of the tunnel lining must investigate the close condition of reinforcement lining and concrete lining.

• Korean Journal of Plant Resources
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• v.34 no.1
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• pp.64-72
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• 2021

This study aimed to identify regions with a suitable growth environment for Ligusticum chuanxing Hort. and use basic data to identify appropriate cultivation and stable production strategies. Four main areas of cultivation were selected and the relationship between growth characteristics (aboveground and underground parts) and weather and soil environment was analyzed. Overall growth was found to be significantly higher in Pyeongchang. Atmospheric and soil temperatures showed a significant negative correlation with overall height from the ground, stem diameter, and growth characteristics of the underground part; leaf length and width were positively correlated. As insolation increased, the growth characteristics, excluding leaf size, showed a positive correlation. Soil characteristics such as organic matter (OM), N, P, and K showed negative correlations with the overall height of the upper part and growth characteristics of the underground part, including stem diameter. Analysis of roots indicated that OM, N, P, and K were essential and were absorbed through the soil. The OM, N, P, and K values in the Pyeongchang area, which showed the optimal growth, were lower than those in other areas. It is believed that these results can be used to select cultivation sites for L. chuanxing and establish cultivation technology in future.