• Explosives and Blasting
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• v.39 no.1
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• pp.10-21
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• 2021

Brittle materials such as rocks and concretes exhibit large strain-rate dependency under dynamic loading conditions. This means that the mechanical properties of such materials can significantly be varied according to load velocity. Thus, the strain-rate dependency is recognized as one of the most important considerations in solving problems of blast engineering or rock dynamics. Unfortunately, however, studies for characterizing the dynamic properties of domestic rocks and other brittle materials are still insufficient in the country. In this study, dynamic tensile tests were conducted using the Hopkinson pressure bar apparatus to characterize the dynamic properties of Geochang granite and high-strength concrete specimens. The dynamic Brazilian disc test, which is suggested by ISRM, and the spalling method were applied. In general, the latter is believed to have some advantages in experiments under high-strain rate deformation. It was found from the tests that there were no significant difference between the dynamic tensile strengths obtained from the two different test methods for the two materials given. However, this was not the expected result before the tests. Actually, authors expected that there be some differences between them. Hence, it is thought that further investigations are needed to clarify this results.

• Journal of the Korean earth science society
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• v.28 no.1
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• pp.75-86
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• 2007

In Korea, it is significantly deficient in the study about tourism geology, which is a new branch of applied geology that would support the growth of ecotourism world-wide. The objectives of this study include (1) the promotion in geodiversity of tourism geology using the data for type and distribution patterns of geological and geomorphological landscape resources and (2) the redoubling of diversity in the environmental interpretation programs offered by the Korea National Parks Service (KNPS). Our field study discovered 212 geological and geomorphological landscape resources distributed in the area of Taean seashore national park. Coastal topography is the most discovered type followed by weathering topography. It is our belief that the aforementioned resources can be utilized as a tourism geological site in assisting the public to understand geological science and to draw their attention and interests after sorting and filtering it out through discussions with geologists and geomorphologists of a consortium. Furthermore, in order to promote the activation of developing user-oriented geotourism sites, it is recommended to keep monitoring on demographical characteristics of geotourists, behavioral characteristics of geotouconrists within the geotourism site and ducting analysis for developing geotourism program and events. And, the research support of geological engineering dealing with the estimation of weathering degree and the development of conservation techniques for the object of geotourism along with the research of environmental science aspects will improve the activation of tourism geology.

• Journal of Soil and Groundwater Environment
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• v.29 no.3
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• pp.1-13
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• 2024

This study investigated the hydrogeochemical and microbiological characteristics of freshwater on Ulleung Island, a volcanic island in the Ulleung Basin on the East Coast of Korea. The shallow groundwater (CSW, NRGW) and the surface water (SISW) samples are classified as Na-HCO₃ type, reflecting an alkaline rock type and an oxidizing environment due to the influence of a highly permeable pyroclastic rock layer. In contrast, the deep groundwater sample (DMW) is classified as Ca-HCO₃ type, suggesting the influence of deep-sourced carbon dioxide and reducing conditions. Microbial communities in the water samples are generally dominated by Proteobacteria, with the relative abundance of major genera varying depending on water quality and environmental conditions. Network analysis reveals the ecological characteristics of microbial communities adapted to specific environments. The presence of pathogenic genera in the shallow groundwater suggests potential groundwater contamination, necessitating appropriate management to ensure its use as drinking water or domestic water. The findings of this study provide valuable insights into the ecological characteristics of Ulleung Island's groundwater resources and can inform future groundwater management strategies.

• Economic and Environmental Geology
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• v.57 no.4
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• pp.431-447
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• 2024

This study aims to analyze the supply and demand trends and regional distribution characteristics of the stone industry through transaction records of the domestic natural stone market. The demand for natural stone is increasing globally, but domestic stone producers are facing financial difficulties due to the influx of low-cost stone, and the government is implementing various support policies, such as mandating the use of domestic stone. However, the influx of low-cost stones has led to management deterioration for domestic stone producers, prompting the government to implement various support policies such as mandating the use of domestic stones. An analysis of the natural stone transaction records from the Public Procurement Service revealed that granite was the main type of rock. The main trading items were natural stone curbs and natural stone slabs, with an average annual transaction amount of approximately 312.8 billion KRW from 2017 to 2021. A comparison of the stone distribution status between the metropolitan area and non-metropolitan areas showed that the metropolitan area had high demand, while non-metropolitan areas served as major supply sources. Cities such as Pocheon in Gyeonggi-do, Iksan in Jeollabuk-do, and Geochang in Gyeongsangnam-do play important roles as major stone suppliers. Based on these results, this study proposes fostering the stone industry tailored to regional characteristics, diversifying distribution channels, and establishing a sustainable supply chain for the sustainable development of the stone industry. Additionally, it emphasizes the need for close cooperation and support among the government, industry, and research institutions.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.316-319
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• 2003

스멕타이트계 점토광물은 팽윤성, 양이온 교환, 층간삽입 (intercalation), 콜로이드 형성, 겔형성, 층간화합물 형성 등의 기능이 있으므로 옛날부터 다양한 산업분야에서 폭넓게 사용되었다. 대표적인 용도는 굴착용 니수, 주형점결제, 농약 증량제, 토목용, 유기 스멕타이트 등이 있다. 그러나, 천연에서 산출되는 스멕타이트는 산지별로 성능이나 특성이 다르고, 불순물 함유등에 의해 안정적인 품질을 얻을 수가 없어, 최종제품의 고품질화, 고기능화에서의 대응이 곤란한 경우가 많고, 또한 양질의 천연 스멕타이트의 매장양은 한정되어 있다. (중략)

• Economic and Environmental Geology
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• v.44 no.1
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• pp.11-20
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• 2011

Geological survey on the occurrence of copper oxide in Suparaura area around Abancay in the south-central part of Peru had been carried out. Geology of the area is composed of granitoids such as granodiorite, tonalite and andesitic porphyry related to Tertiary igneous activity, Ferrobamba formation with Cretaceous limestone and sandstone in descending order. Red sandstone is widely distributed and emplaced with their attitude of $N70^{\circ}W$ strike and $60^{\circ}NE$ dip. Copper oxides were mineralized along the bedding plane of red sandstone with maximum width of 30 cm. Ore-body structure bounding red sandstone strata have different occurrence characteristics with generally known porphyry system in terms of alteration, mineral assemblage and occurrence mode. Therefore, it is thought to be stratiform sediment-hosted copper (SSC) deposits genetically corresponding to Mississippi-valley type from preliminary study.

• The Journal of Engineering Geology
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• v.4 no.1
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• pp.43-55
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• 1994

Two thematic maps on environmental geology were produced in the Cheong-Ju area, with aids of GIS technique. They are landslide hazards & risk maps and cut-fill maps. The models of environmental geology map and digital database were established for creation of these maps by means of cartographic simulation in GIS. These special maps are very important for understanding the environmental characteristics of the study area, and can be applied in the establishment of the regional land use planning. For instance, the landslide hazard and risk map can play very important role in the road design, and cut- fill map in the construction work in the area. The scoring system for landslide analysis was developed through the evaluation of each environmental geologic factor in relation to the others and reflects the relative imporatance of each factor. The excavation index(easy, intermediate and difficult) was evaluated through cut-fill analysis, and they can be very useftil for assessing the degree of excavation difficulty.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.509-513
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• 2004

현장 균열망의 연결성 및 이에 따른 수리지질학적 특성을 규명하기 위하여, 기존의 통상적인 조사 기법을 한 지역에 집적하여 그 결과에 대한 통합해석을 수행하였다. 본 연구에 적용된 조사 방법은 양수시험, 물리검층, 다중심도 수리화학 분석, 전기비저항 토모그래피, 시추 코어 검층 등의 기련 특성 조사와, 추적자 시험, 다중 심도 수직 유향유속 시험 등 구간별 특성 조사 등이다. 이러한 조사 결과 본 조사 지역 내 균열의 전반적인 분포 특성을 확인할 수 있었으며, 각 균열의 수리적 특성에 대한 기본적 특성을 확인할 수 있었다. 특히 추적자 시험과 유향유속 시험 결과를 통해 각 관정간의 균열을 통한 연결성에 대한 중요한 정보를 도출할 수 있었다. 이러한 성과는 추후 percolation, connectivity 등 모델 개념의 현장화를 위한 연구의 선행 연구로서 그 의미를 자리매김 할 수 있을 것이다.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.493-507
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• 2018

The Wooseok deposit in Jecheon belongs to the Hwanggangri Mineralized Distict of the northeastern Ogcheon Metamorphic Belt. Its geology consists mostly of limestone of the Choseon Supergroup and the Cretaceous Muamsa granite intruded at the eastern area of the deposit. The deposit shows vertical occurrence of skarn and hydrothermal vein ores with W-Mo-Fe and Cu-Pb-Zn mineralization and skarn is developed only at lower levels of the deposit. Skarn minerals are replaced or cut by ore minerals in paragenetic sequence of magnetite-hematite, molybdenite-scheelite-wollframite, and higher abundances of pyrrhotite-chalcopyrite-pyrite-sphalerite-galena. Garnet has chemical compositions of $Ad_{65.9-97.8}Gr_{0.3-32.0}Pyr_{0.9-3.0}$, corresponding to andradite series, and pyroxene compositions are $Hd_{4.5-49.7}Di_{42.3-93.9}Jo_{0.5-7.9}$, prevailing in diopside compositions, both of which suggest oxidized conditions of skarnization. On the FeS-MnS-CdS ternary diagram, FeS contents of sphalerite in vein ores decrease with increasing MnS contents from bottom to top levels, possibly relating to W mineralization in deep and Pb-Zn mineralization in shallow level. Sulfur isotope values of sulfide minerals range from 5.1 to 6.8‰, reflecting magmatic sulfur affected by host rocks. W-Mo skarn and Pb-Zn vein mineralization in the Wooseok deposit were established by spatio-temporal variation of decreasing temperature and oxygen fugacity with increasing sulfur fugacity from bottom to top levels.

• Economic and Environmental Geology
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• v.41 no.6
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• pp.763-771
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• 2008

Uncertainties are pervasive in engineering geological problems. Therefore, the presence of uncertainties and their significance in analysis and design of slopes have been recognized. Since the uncertainties cannot be taken into account by the conventional deterministic approaches in slope stability analysis, the probabilistic analysis has been considered as the primary tool for representing uncertainties in mathematical models. However, some uncertainties are caused by incomplete information due to lack of information, and those uncertainties cannot be handled appropriately by the probabilistic approach. For those uncertainties, the theory of fuzzy sets is more appropriate. Therefore, in this study, fuzzy reliability analysis has been proposed in order to deal with the uncertainties which cannot be quantified in the probabilistic analysis due to the limited information. For the practical example, a slope is selected in this study and both the probabilistic analysis and the fuzzy reliability analysis have been carried out for planar failure. In the fuzzy reliability analysis, the dip angle and internal friction angle of discontinuity are considered as triangular fuzzy numbers since the random properties of the variables cannot be obtained completely under the conditions of limited information. In the study, the fuzzy reliability index and the probabilities of failure are evaluated from fuzzy arithmetic and compared to those from the probabilistic approach using Monte Carlo simulation and point estimate method. The analysis results show that the fuzzy reliability analysis is more appropriate for the condition that the uncertainties arise due to incomplete information.