• Tunnel and Underground Space
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• v.31 no.4
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• pp.243-269
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• 2021

Since the early 2010s, the social importance of research and practical projects targeting deep geological disposal of high-level nuclear waste, underground CO₂ storage and characterization of deep subsurface by borehole investigation has been increasing. In this regard, there is also a significant increase in the need for in situ test technology to obtain quantitative and reliable information on the hydraulic characteristics of deep rock mass. Through years of research and development, we have independently set up Deep borehole Hydraulic Test System (DHTS) based on the key apparatuses designed and made with our own technology. Using this system, high precision constant pressure injection tests were successfully completed at the two 1 km boreholes located in Mesozoic granite and sedimentary rock regions, Gyeongju. During the field tests, it was possible to measure very low flow rate below 0.01 l/min with micro flow rate injection/control module. In this paper, the major characteristics of DHTS are introduced and also some results obtained from the high precision field tests under the deep and low permeable rock mass environment are briefly discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.4
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• pp.113-125
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• 1984

Water supply has been mainly dependent on the construction of the dams in Korea. It is difficult, however, to continue to construct dams for many reasons, such as the decrease of construction sites, the increase of construction costs, the compensation of residents in flooded areas, and the environmental effects. Water demands have increased and are expected to continue increasing due to the concentration of people in the cities, the rise of the living standard, and rapid industrial growth. It is acutely important to find countermeasures such as development of ground water, desalination, and recycling of waste water to cope with increasing water demands. Recycling waste water includes all means of supplying non-potable water for their respective usages with proper water quality which is not the same quality as potable water. The usages of the recycled water include toilet flushing, air conditioning, car washing, yard watering, road cleaning, park sprinkling, and fire fighting, etc. Raw water for recycling is obtained from drainage water from buildings, toilets, and cooling towers, treated waste water, polluted rivers, ground water, reinfall, etc. The water quantity must be considered as well as its quality in selecting raw water for the recycling. The types of recycling may be classified roughly into closed recycle systems and open recycle systems, which can be further subdivided into individual recycle systems, regional recycle systems and large scale recycle system. The treatment methods of wastewater combine biochemical and physiochemical methods. The former includes activated sludge treatment, bio-disc treatment, and contact aeration treatment, and the latter contains sedimentation, sand filtration, activated carbon adsorption, ozone treatment, chlorination, and membrane filter. The recycling patterns in other countries were investigated and the effects of the recycling were divided into direct and indirect effects. The problems of water reuse in recycle patterns were also studied. The problems include technological, sanitary, and operational problems as well as cost and legislative ones. The duties of installation and administrative organization, structural standards for reuse of water, maintenance and financial disposal were also studied.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.471-482
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• 2008

This study was carried out to investigate the contamination characteristics of surface water, soil water and groundwater around and in antimony waste landfill site in Wonsung-ri, Yeonki-kun, Chungnam. The waste disposed in the study was excavated and transported to the other site in several years ago. For this study, we collected 35 water samples including groundwater, soil water and surface in the study site and also collected 2 groundwater samples from a comparison site. The data of chemical analysis of soil water samples show the antimony concentration of $48.75{\sim}74.81\;ppb$, which is much higher than groundwater in a comparison site and is highly excess than regulation level for a drinking water of some advanced countries. A relatively high antimony concentration was detected in three stream water samples nearby landfill site and two groundwater samples. Fe and Mn contents in soil water and stream water were measured as maxium 6.5 mg/L and 7.3 mg/L, respectively. Although other heavy metals of water samples in the study site are higher concentration than water sample of comparison site, their absolute levels are lower than regulation level for a drinking water. The chemical data of water samples are plotted widely from Ca - $HCO_3$ type to Ca - ($Cl +SO_4+NO_3$) type. Some groundwater show high contents of potassium and nitrate, which would come from fertilizer and sewage. Conclusively, some heavy metals including antimony have been still remained under the soil surface of the landfill site in the past. These metals have leaked out into nearby stream and groundwater system, and threaten the ecology, crops and the health of residents in this site. Therefore, the government have to prepare the strategy to prevent the diffusion of heavy metals into aquatic environment and have to process the reclamation work for contaminated site. It is also necessary to make a regulation level of the antimony concentration for a drinking water and soil environment in Korea.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.50-57
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• 2006

Development of structures such as slope and tunnel, waste disposal, oil and LPG storages, and underground power house and so on, is increasing with the year. The method for appropriate estimation of rock state such as fresh or damaged rocks is also requested with increasing structural development. On these purposes, seismic logging system, which is a simple and easy way for handling as well as small and light, has been developed. Seismic logging method is one of logging tests, which is able to evaluate the state of rock mass with various shapes and is possible to obtain the relatively accuracy data at situ state. In addition, seismic logging method is at to apply to estimate structural behavior, before and after support installed. According to the results obtained from this study, firstly, it is clear that the extent of damage in rock slope due to blasting is able to be evaluated with quantity using seismic logging method, moreover to decide the damage zone in rock slope reasonably. Secondly, it is expected that installing depth of support is able to be decided more effectively and economically, using the results of seismic logging data. Finally, seismic logging method is also able to be applied safety supervision of structures, before and after support installed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.151-159
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• 2020

This study examined the environment and landscape aspects of rural villages, which are based on agriculture, to regenerate a disappearing rural village. The lifestyle and living conditions in this area were examined and the field survey of this area was carried out. The main negative factors at the rural landscape and living environment, such as rural households garbage, compost piles, and farming wastes, were found. An improvement plan of the landscape in this area was then determined. The disposal conditions according to the garbage types were analyzed through a survey with the residents directly. Through this survey, the current negative factors in landscape were checked and various improvement methods were assessed. Based on this, an institutional framework about landscape improvement of a village was developed, and a fundamental resource that can improve the environment of rural communities by this system is suggested.

• Korean Educational Research Journal
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• v.38 no.3
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• pp.167-188
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• 2018

The purpose of this study is to suggest safety education on life science inquiry activity, which subjects on the exploration and autonomous research to the relevant topics, mainly done by the science high school students. Investigation was made on subjects of research activity proposed from Life science and autonomous research from science high school students by examine thoroughly 2009 revised education curriculum. To prevent school laboratory accidents, education of basic safety regulations and general precautions should be repeatedly notified by clear statements and expression to each topic. Expressing the safety factors considering the themes of autonomous inquiry and activities presented in the course of education should be done, so that students should not experience laboratory accidents by reason of ignorance. From the beginning of organization to performing research, safety rules about disposing chemicals and tools wastes occurring during research should be noticed and expressed in precautions following waste disposal system should be adopted. It is necessary to level up the accessibility of information about the laboratory safety rules to confirm to the every student, and also ensure the takeover of the clean-up and use of utilities at the time of search end in order to prevent the incidence of laboratory accidents during the thorough stages of biological inquiry activities.

• Economic and Environmental Geology
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• v.39 no.4 s.179
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• pp.441-450
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• 2006

The on-land seismic survey in Korea was begun in mid-1960s. Kim et al.(1967) of Korea Geological Survey reported on the result of gravity and seismic reflection surveys conducted in the Pohang area for the period of 1963-64 to assess its possibility of oil entrapment. Hyun and Kim (1966) carried out a refraction survey on the tunnel wall. Since then, the KGS geophysicists had conducted seismic surveys on Kyungsang sedimentary basin as a main project for several years. In 1970s, on-land seismic surveys had been conducted for various purposes such as site investigation for the nuclear power plants and industrial complex, exploration for ground water, mineral resources and underground tunnel. The first reflection survey with CMP acquisition was attempted in 1978 by using a digital recording system. But most of on-land seismic surveys had employed the refraction method until 1980s. In 1990s, high resolution reflection and various borehole seismic surveys such as tomography, uphole, downhole, cross-hole methods have been attempted by universities and engineering companies. The applications of on-land seismic surveys have been enlarged for both academic and industrial purposes such as investigation of geologic structure of the fault and tidal flat area, construction of highway, railroad and dam, geothermal energy and mineral resource exploration, environmental assessment for waste disposal sites and archaeological investigations. In 2002, the first crustal seismic survey was carried out on the profile of 294km length across the whole peninsular. It is expected that the advanced technology and experience acquired through offshore seismic surveys, which have been conducted in continental shelf of Korea and foreign oil fields, will stimulate the more active on-land seismic explorations.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.6
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• pp.575-593
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• 2012

This paper briefly introduces the scope and objectives of SKB Task 8, which is an international cooperative research project. In addition, the hydraulic behaviors of bentonite buffer focusing on the interactions between bentonite and a rock mass with a joint were investigated using TOUGH2 code as part of a sub-mission of Task 8a. The effects of a rock joint and high capillary pressure of bentonite on the re-saturation properties and pressure distribution in a buffer were identified and successfully incorporated in the TOUGH2 code. Based on the numerical results, it was found that the speed of re-saturation in bentonite surrounded by a rock mass with a joint is 2.5 to 12 times faster than that in a condition without a rock joint, while the degree of saturation in the lower part of the buffer material is generally higher than in the upper part in both the cases of with and without a joint. It can be anticipated that the results obtained from this study can be applied to an estimation of the full saturation time and a determination of optimum thickness with regard to the design of the bentonite buffer in a high level waste disposal system.

• The Korean Journal of Community Living Science
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• v.25 no.1
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• pp.99-111
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• 2014

To verify welfare needs, rural health and environmental factors were compared between agricultural and nonagricultural groups over the past 10 years. Based on a survey of rural life by the Rural Development Administration, whose sample included agricultural (72.8%) and nonagricultural (27.2%) groups, all factors were analyzed using SAS ( 9.3). For rural home heating, the use of oil boilers (77.2%-78.0%) decreased (53.0%-53.7%) over the same period, whereas that of electric boilers increased (21.9% and 13.5% for agricultural and nonagricultural groups, respectively). The joint water- supply increased, and the use of flush toilets (52.4% to 84.5% in the agricultural group and 64.6% to 81.4% in the nonagricultural group) and hot-water bathing was higher in the agricultural group (79% to 92.6%) than in the nonagricultural group (72.2% to 87.6%) at the p<0.001 level. Incineration accounted for the largest portion of household waste until 2006, when it was replaced by other treatment methods such as the pay-per-treatment option (44.4% and 68.3% in the agricultural and nonagricultural groups, respectively) (p<0.001). Garbage disposal in 2001 was mainly burial or animal feed, but separate collection increased in 2010 (42.2% and 64.3% in the agricultural and nonagricultural groups, respectively) (p<0.001). The self-perception of health was lower in the agricultural group than in the nonagricultural group (2.96 to 2.74 on a five-point scale in the agricultural group and 3.07 to 2.98 in the nonagricultural group). Drinking decreased less in the agricultural group (criteria: one point once a week,; 1.48 to 1.20) than in the nonagricultural group (1.13 to 0.80) at p<0.001, and a similar pattern was found for smoking (p<0.001). Health screening decreased in the last 10 years (scoring based one point/1-2 times per year,: 0.94 to 0.64 in the agricultural group and 1.08 to 0.69 in the nonagricultural group;p<0.01). These results indicate that various health and environmental factors were less favorable to farmers except for bathing in comparison to nonagricultural living in the same area. This suggests that people in agriculture are less likely to live and work in favorable environments than those outside the sector and thus indicates a need for more attention to the national health welfare system for farmers for systematic realization.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.61-74
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• 2012

Industrial complexes in Korea have been vigorously established by economic development plan and development policy of industry in 1960s. Recently, Korean government has promoted Eco Industrial Park (EIP) project to recycle by-products and wastes in industrial park In this study, we analyzed the physical and chemical properties for the sludges discharged from A industrial complex. And we investigated the economic feasibility and environmental impact of sludge to energy facilities. The analysis results indicated that the petrochemical industry were 92% in sludge production, the highest treatment amount was landfill, followed by incineration and recycling and then ocean disposal. Wastewater sludge and process sludge samples are collected and analyzed to use as basic data on economic feasibility and environmental impact. Weighted average heating value of sludge samples was 3,891kcal/kg. Based on this data, installation and operation costs, operation returns of operating the drying facility are estimated, compared with cogeneration facility. And this study examines how the payback period of each simulation(total 8 case) with the important parameter changes. As a result, it was found that what needs the shortest payback period is 3years with connection of drying facility and cogeneration facility based on the government's financial subsidy system.