• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.3-10
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• 2003

Soil and groundwater contamination by petroleum hydrocarbon products is only one of many environmental problems in Korea. However, many environmental consulting companies have been targeted their business on this subject because the petroleum-oil-lubricant (POL) products have been widely used product and accidental releases of the products from storages resulted numerous small and large contaminated sites throughout Korea. Therefore, many small and large companies are actively participating in environmental assessment and remediation projects for the POL contaminated sites. Remedial technologies for the POL contaminated sites have been developed for many years by government and private institutions throughout the world. Development of a new decontamination technology for the POL contaminated sites is no longer attractive issue in research community because scientific bases of most cost-effective remedial technologies are well understood and have been used in the field by commercial sector. Numerous sites contaminated by underground tanks at gas stations have been remediated by relatively small companies in this country. We should appreciate their noticeable contributions as a frontier under very difficult market environment in Korea. We heard many successful stories as well as a few failure stories. Soil-groundwater remediation of POL contaminated site is not a simple task as shown in the text books or protocols. Therefore, failure risk is always with us, which requires continuous efforts for improvement of the technologies by the users and developers. In this presentation, author will discuss technical problems encountered and improvement made during implementation of several remedial technologies applied by Samsung Environmental Team. This is not a presentation about research or case study. We want to share our thought and experience with environmental engineers actively engaged in soil and groundwater remediation projects in Korea.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.237-242
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• 2014

In this paper, we find out the lifetime index in order to determine the time-dependent trend of deteriorating performance of 6.6kV high-voltage power cable in operation at a power station. The cable systems used in our study have been in operation for 13 years. With measurements for the 13 years, we analyzed the insulation resistances. By developing measuring equipment (comprized mainly of transformer, temperature sensor, and LPF) operating by the three-phase electric power, we analyzed the changing characteristics of insulation resistance of power cable. In contrast to 22kV cables, 6.6 kV cables have thicker insulation. Therefore the characteristics of 6.6kV cables are different from that of 22kV cables. The study found that as time passes, the insulation resistance does not decrease continuously; it decreases to a certain value, then does not decrease any more and shows properties of oscillation. We could not detect the process of deterioration in the preceding twelve years. The cable system showed great stability so that deterioration was not apparent. In this case, it is not possible to measure the future life indices of power cables because the lifetime indices are not predictable

• Journal of the Korean GEO-environmental Society
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• v.21 no.9
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• pp.5-14
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• 2020

This study analyzed the reinforcement effect by conducting laboratory test, model test and program analysis to utilize the surface stabilizer used for the restoration work of collapsed slopes as a reinforcing material for aging reservoirs that exhibits a curing reaction similar to cement. Based on the results of the laboratory test, a model test and program analysis were performed by applying 9% of the mixing ratio. As a result, when the surface stabilizer was used in aging reservoir, it was found that the flow of water only occurred on part of the slope and underground in reservoir. And the water flow could be reduced inside the reservoir. In addition, it was analyzed that the seepage discharge could be reduced by about 42% and the saturated area within the reservoir by about 73%, thereby securing the stability of the aged reservoir.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.389-400
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• 2020

A construction project is a designed product made up of labors, materials, and installations in the project positioned on the ground and may include the underground and ground section, and the section in water or on the water surface. It is a civil, industrial, transport, agricultural and rural development, infrastructure, or some other. A key phase in the life cycle of these construction projects is the implementation when building products are made directly with workers, equipment, materials, and managers. If there is a lack of management experience, information, and problem-solving solutions to tackle the risks faced by contractors, especially foreign ones, will fail in controlling the project's cost. This study was conducted with investigations, discussions, and evaluation of the factors that lead to cost overruns in the construction projects of international contractors in Vietnam. The principal component analysis (PCA) showed that those factors that influence cost overruns these construction projects fall into five general groups, including factors related to (i) the owners, (ii) the foreign contractors, (iii) the subcontractors and suppliers, (iv) state management, and (v) the project itself. Besides, the study proposes solutions to limit cost overruns in construction projects and improve the profitability of international contractors in Vietnam.

• Journal of Korea Water Resources Association
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• v.34 no.5
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• pp.439-448
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• 2001

A two-dimensional finite difference numerical model was developed in order to simulate two-phase fluid flow in a single fracture. In the model, variation of viscosity with pressure and that of relative permeability with water saturation can be treated. For the numerical solution, IMPES method was used, from which the pressure and the saturation of water and gas were computed one by one. Seven cases of model test using parallel plates for a single fracture were performed in order to obtain the characteristic equation of relative permeability which would be used in the numerical model. it was difficult to match the characteristic curves of relative permeability from the model tests with the existing emperical equations, consequently a logistic equation was proposed. As the equation is composed of the parameters involving aperture size, it can be applied to any fracture.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.2 s.32
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• pp.21-28
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• 2005

Local government has constructed GIS DB for efficient business achievement and effective management of complex city facilities and has been developing and utilizing application systems, such as Underground Facility Management System Road Management System and so on. However, Facility Management System is providing functions for business, but not for GIS DB's maintenance. City facilities GIS DB managed by GIS technical expert collects basic figure and attribute information through survey and field investigation and is constructed via complex process, such as structurize editing etc. So it has been concerned that the update and confidence of CIS DB can be lower if a business man who does not have enough experiences about Facility Management System operates it by himself. Therefore, functions that enable business users to operate Facility Management System easily should be provided.

• Tunnel and Underground Space
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• v.14 no.1
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• pp.1-15
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• 2004

The development of high-performance shotcrete lining is essential in improving the long-term durability of tunnels and in introducing single-shell tunnelling methods, where shotcrete as well as rockbolts are used as permanent support members. In this paper, new and advanced admixtures to improve shotcrete performance are introduced. In addition, requirements for mechanical properties as well as test items for quality control of shotcrete are summarized. A case study on the application of the pneumatic pin penetration test which can estimate compressive strength of shotcrete more easily and quickly is also illustrated. Previous studies to analyze the behaviors of shotcrete lining by considering its transient hardening and to carry out the sensitivity analysis of the design parameters of shotcrete lining are discussed to give fundamental concepts on rock-support interactions. Representative single-shell tunnelling methods where high-performance shotcrete lining is applied as a permanent support are also introduced.

• Tunnel and Underground Space
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• v.24 no.1
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• pp.55-66
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• 2014

In this study, a joint survey system was developed to efficiently analyze geometrical characteristics of joint structures in rock mass using photogrammetric technique. The system includes both hardware and software. The hardware consists of a high resolution image camera for photographing image of a surface of rock body, a direction controlling system for adjusting the attitude of camera, and a digital compass for measuring the rotation angle of camera. The software was also developed in order to analyze the orientation, density, mean length of joints revealed on the images of rock surfaces. The software developed in this study was named as JointeXtractor. As applying this system into several field measurements, the orientation, density, mean length of joints could be quantitatively measured through analyzing the images of rock surfaces, in which the case of a difficult-to-access area was especially included for the test of the system.

• Tunnel and Underground Space
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• v.25 no.3
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• pp.221-230
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• 2015

This study examined and analyzed several mine management software programs developed in domestic and oversea countries. In the oversea countries, many companies have developed and commercialized mine management softwares such as Dispatch, $Cat^{(R)}$ $MineStar^{TM}$ and FARA. These softwares provide many functionalities including real-time machine tracking, machine assignment optimization, productivity management, equipment health monitoring and remote control. For the domestic cases, this study reviewed two software programs (i.e., GEMISIMS, Truck-Shovel fleet optimization) developed by several researchers because there is no mine management software currently commercialized in Korea. In addition, this paper reports the two cases at the Jwaneng mine in Botswana and at the Robinson mine in United States where mine management software programs are used to support mine operations.

• Tunnel and Underground Space
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• v.25 no.6
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• pp.534-542
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• 2015

Round trip activity occurs discretely due to the abrasion of drill bit in the deep drilling project. Round trip has great impact on the drilling performance because it takes more time to change a drill bit as the depth goes deeper. Therefore, a reliable prediction technology of the round trip should be secured for feasibility analysis and effective management of the drilling project. Lee et al. (2013) developed the TOSA (round trip occurrence simulation algorithm) which can analyze the depth and timing of round trip occurrence at each abrasion state of bit. However, TOSA has weakness that it takes long time for simulation because the number of simulation increase exponentially as increasing the number of simulation section. This study developed the TOSA based round trip performance prediction module using genetic algorithm for simulating in a short time and verified simulation results.