• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.161-169
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• 2004

In this study, a similarity rule is thoroughly discussed for tunnelling model tests which can simulate actual ground conditions. Based on this prior consideration, theoretical works are performed to simulate a real ground condition into a gravitational field with a similarity. A process is arranged to determine a lining condition in laboratory tests for a sandy ground tunnel.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1057-1059
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• 1999

Recently, increased demand of electrical energy caused additional installation of underground power cable, Industrialization of metro makes civil works difficult. So installed ducts became a key of underground power transmission, LG cable set to work development of high stress cable. LG cable stated in 1996, got a certificate of type test in 1998, and applied at domestic site in Nov. 1999. High stress cable has some merit, decrease of civil cost, reduction of work time, by reason of decrease of dia. and weight, and economical system design, so LG cable has a good merit in comparison with competitive company in domestic and foreign market.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.9-13
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• 2009

Recently, construction in downtown is often done closely at the adjacent building. In this case, underground construction need to Basement Composite Wall(BCW) construction. However, generally, during the construction process of BCW form works have many problems that are narrow working space and inefficient time consuming. Despite of these problems, there was no quantitative research for the work time of BCM assembly. Therefore, in this study, work time of CBW form assembly in underground construction is identified by the work analysis. The results of this study reveal that buttress work of basement form take lots of time in the entire work process of Basement Composite Wall form assembly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.52-56
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• 2001

Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB(Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE> LLDPE = MDP E> LDPE and WVT ratio was HDPE

• Tunnel and Underground Space
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• v.6 no.1
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• pp.10-18
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• 1996

Arched openings are generally excavated in underground construction works. Since stress distribution around openings depends on geological structure in rock mass, any shape of arched openings fully conformed with in-situ stress condition should be recommended to maintain mechanical safety of structures. Shape of arched openings is specified by both roof curvature and height-width ratio, and especially this report presents deformation behaviors related with roof curvature. Scale model tests and numerical studies of various shaped openings are conducted, where rectangular opening shows the greatest convergence. Through the anlayses of various arched opengings, as radius of roof curvature is increased, roof lowering and sidewall closure are remarkably increased, whereas floor heaving is increased little by little. By the way, it is useful that displacements of openings are roughly estimated in the stage of preliminary investigation. To find out elastic displacements of arched openings with any roof curvature, regressional formula and charts by least square method are represented. In addition elastoplastic deformation behavoirs of arched openings concerning associated adn non-associated flow rule are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.903-909
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• 2001

Apartment and large residence buildings are necessary to ensure a comfortable noise/vibration environment. So. it must be performed a anti-vibration/noise evaluation at early design stage, such as utility room arrangement, machinery installation method and so on. In this paper. environment noise status on problem areas, which was issued by resident. was investigated to understand the noise transmission property generated from underground machinery room and to device a optimized countermeasure in order to enhance noise environment. Also, the measured noise levels before and after modification works are compared to confirm the effectiveness of proposed countermeasure.

• Spatial Information Research
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• v.18 no.4
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• pp.23-32
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• 2010

Water mains underground facilities are essential components to make up urban infrastructure. In order to manage these water mains underground facilities systematically and scientifically, GIS (Geographic Information System) had been constructed. For the sake of construction of GIS for water mains underground facilities, an exact underground detection and the construction of DB (Data Base) for buried water mains underground facilities should be preceded. In this study, in order to find out the ways to improve exact detection rate of data, the statistical analysis for the causes of detection raw degradation was done, and standardization methods of detection through a case study were suggested, When water mains underground facilities were measured, the detection of non-metallic water pipes was not carried out. The reason was that the results of detection was uncertain and detection was difficult because the assessment of public measurements was vulnerable. Moreover, due to the absence of standardized operating regulations for detection, systematic surveys weren't conducted. In this study, methods to standardize works over the detection of water mains underground facilities were presented so that we can improve the detection rate when we are doing that. As the proposals to improve detection rate, effective performance assessment over non-metallic pipes were presented, and related issues to supplement work regulations of public survey were described systematically.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.4
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• pp.343-350
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• 2022

The computerization project for underground facilities in Korea began in earnest after the city gas explosion in Seoul in 1994, and the Daegu subway explosion in 1995. As such a large-scale gas explosion accident caused enormous economic loss including human casualties and potential benefits, the need for computerized for efficient management of underground facilities was greatly emphasized in society. Meantime, computerization of underground facilities has been carried out according to the basic plan for building national geographic information system. In this study, problems were identified based on the current status of construction and management of underground facility information, as well as laws and regulations, and directions for establishing quality standards were presented. In addition, construction work standards such as 「Public Survey Work Regulations」, design standards, standard specifications, and technical specifications, gas technology standards, design standards, and communication works so that underground facility information can be linked and utilized in construction work by examining the linkage of the underground facilities, the targets that can be used for quality level information on underground facilities were derived, and a proposal to revise the construction standards was presented. In the future, if the quality standards are established, it is expected that the accuracy and utilization in the construction field will be increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.123-127
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• 2008

As buildings becoming higher and more enormous the portion of steel works has been increased, which makes the schedule planning and management more significant. However, in actual construction sites, management is more based on a manager's construction experience than productivity data accumulated in previous projects. Moreover, most of the existing studies also featured a theoretical approach rather than an analysis of data straightforwardly collected in sites. In this study, a steel-erection site was visited to collect productivity data. The study found that there were significant disparities between aboveground work productivity and underground work. However, the productivities of 'first node on ground' and 'second node on ground' were estimated similar. The productivity data collected and factors affecting the productivity will help managers to plan and control their similar steel-erection works. This study will also be beneficial for those performing related studies.

• Tunnel and Underground Space
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• v.4 no.3
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• pp.287-296
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• 1994

Safety-related structures of power plants have to be protected against the effects of possible hazards and natural phenomena. Earthquakes are considered a major dynamic design loading as a requirement of plant design, but the effects of blast-induced vibratons are not. Due to the difficulties of obtaining construction site for new plants, following ones are inevitably being built in the site adjacent to existing power plants. Therefore considerable thought has been recently given to the dynamic loading generated by blasting works near the plants. In this paper, discussed is applicability of existing vibration standards and industrial codes to the blasting works near safety related structures. Also evaluated are the parameters for the safe vibration limits such as measure of vibration level, frequency consideration, structure response, propagation equation, etc.