• Geomechanics and Engineering
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• 제20권6호
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• pp.537-546
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• 2020

Oil and natural gas reserves have been recognised abundantly in clayey rich rock formations in deep costal reservoirs. It is necessary to understand the sedimentary history of those reservoir rocks to well explore these natural resources. This work designs a group of laboratory experiments to mimic the physical process of the sedimentary clay-rich rock formation. It presents characterisation results of the physical properties of the artificial clayey rocks synthesized from illite clay, quartz sand and brine water by high-pressure consolidation tests. Special focus is given on the effects of illite clay content and high-stress consolidation on the physical properties. Multi-step loaded consolidation experiments were carried out with stress up to 35 MPa on mixtures constituting of the illite clay, quartz sand and brine water with five initial illite clay contents (w=85%, 70%, 55%, 40% and 25%). Compressibility and void ratio were characterised throughout the physical compaction process of the mixtures constituting of five illite clay contents and their water permeability was measured as well. Results show that the applied stress induces a great reduction of clayey rock void ratio. Illite clay contents has a significant influence on the compressibility, void ratio and the permeability of the physically synthesized clayey rocks. There is a critical illite clay content w=70% that induces the minimum void ratio in the physically synthesised clayey rocks. The SEM study indicates, in the high-pressure synthesised clayey rocks with high illite clay contents, the illite clay minerals are located in layers and serve as the material matrix, and the quartz minerals fill in the inter-mineral pores or are embedded in the illite clay matrix. The arrangements of the minerals in microscale originate the structural anisotropy of the high-pressure synthesised clayey rock. The test findings can give an intuitive physical understanding of the deep-buried clayey rock basins in energy reservoirs.

• 건축역사연구
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• 제11권4호
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• pp.117-128
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• 2002

This paper aims at proposing constructional intention and aesthetic consciousness in the architecture of Jajang-temple, which was originally built by the great monk, Jajang in 7c. The results are as follows : 1) The layout and form of buildings in Jajang-temple were remarkably followed the situations and shapes of natural rocks related to Gumwa legend about the original establishment of the temple. 2) As natural rocks were penetrated into both the inner and outer space of buildings and so artificial skills were more or less restrained, it seems to be short of geometrical regularity, symmetry and formal integrity. 3) However it can be said that these architectural treatments were based on the aesthetic consciousness, so called In-Cha and Jol-Bak, which were conceived by intellectual elites in Chosun dynasty.

• 헤리티지:역사와 과학
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• 제42권1호
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• pp.20-39
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• 2009

남 북한 천연기념물에 대해 조사 및 보고된 문헌을 토대로 지질분야 천연기념물 현황을 비교하였다. 비교 분석된 항목들은 남한은 암석, 천연동굴, 화석, 일반지질의 4가지 그리고 북한은 암석, 화석, 지층, 약수, 온천, 지형, 폭포, 호수, 천연동굴, 담소의 10가지이다. 남한에서는 북한과는 달리 지질분야 천연기념물이 상대적으로 적게 지정 보호되고 있는 것으로 나타났다. 북한에서는 남한과는 다르게 지층의 구조(습곡, 단층) 및 산업자원을 채굴하는 광산의 대표적인 노두를 천연기념물로 지정 보호하고 있는데, 이 유형들은 우리나라에서 일어난 지구조운동의 방향과 크기, 시기 및 형성요인 등을 밝혀주므로 천연기념물로 지정할 가치가 있는 것으로 판단된다. 남한에서 지질분야 천연기념물 지정건수의 연도별 변화를 보면 크게 3시기로 구분되며, 각 시기의 평균지정건수는 1.1건, 0.1건, 2.6건으로 변하였다. 지질분야 천연기념물 지정건수가 가장 많은 지역은 남한은 제주도로 그리고 북한은 강원도로 나타났으며, 산업화와 도시화가 상대적으로 덜 발달된 지역의 천연기념물이 더 잘 보존된 것으로 여겨진다.

• 암석학회지
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• 제26권4호
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• pp.353-360
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• 2017

남한산성 외성은 성벽의 붕괴와 부재의 탈락으로 인해 보존처리가 필요한 실정이다. 이 연구에서는 남한산성 외성의 성벽부재를 대상으로 암석학적 연구를 실시하고 주변의 지질조사를 통해 산지를 추정함과 동시에 외성의 정비 시 활용 가능한 대체석을 제시하고자 한다. 남한산성 외성부재는 호상편마암, 안구상편마암, 화강암질편마암, 반상변정질편마암으로 이루어져 있으며 화강암질편마암이 가장 많이 사용되었다. 주변에 분포하고 있는 암석의 암석기재적 특징과 야외산상, 남한산의 채석흔적으로부터 남한산을 포함한 일대가 석재의 산지로 추정된다. 외성의 주요 축성재료들의 물성시험 결과와 축성에 사용된 부재의 현황을 종합한 결과 외성의 보수정비를 진행할 경우 대체석으로는 화강암질편마암이 적절할 것으로 판단된다.

• 보존과학회지
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• 제37권4호
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• pp.380-390
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• 2021

The purpose of this study is to scientifically analyze the rocks of the Obongsan Mountain in Boseong, Jeollanam-do, which contains the largest extant quarry of Gudlejang (flat stone for heating) in Korea, and to scientifically determine the petrological characteristics of the area and the reasons for its use as a quarry. The rocks in the quarry are composed of light-green lapilli tuff, containing various types of lithic fragments and crystalline fragments in a vitreous matrix consisting of the fine feldspar crystals. The main constituent minerals were identified as quartz, plagioclase, mica, chlorite and opaque minerals. When the major element compositions were plotted on a Na₂O+K₂O versus SiO₂ diagram, all samples were situated in the same compositional area as rhyolite. In addition, the result of magnetic susceptibility measurement also showed a similar range of values, of 1.30 ~ 4.85 (×10^-3 SI), indicating that samples were fractionated from the same magma. Both rock types showed similar apparent specific gravity values of 2.32 ~ 2.60. In particular, plate-shaped joints are well developed in the Obongsan Mountain area, and many areas exhibit talus terrain. In conclusion, the rocks of this area is interpreted to used for a site of Gudlejang quarrying, because the rocks were easily obtainable due to the terrain characteristics, and their petrological properties made them suitable for use as Gudlejang stone.

• Geomechanics and Engineering
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• 제33권5호
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• pp.453-462
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• 2023

Intermediate Geomaterials (IGMs) are natural formation materials that exhibit the engineering behavior (strength and compressibility) between soils and rocks. The engineering behavior of such material is highly unpredictable as the IGMs are stiffer than soils and weaker/softer than rocks. Further, the characterization of such material needs exposure to both soil and rock mechanics. In most conventional designs of geotechnical structures, the engineering properties of the IGMs are either aligned with soils or rocks, and this assumption may end up either in an over-conservative design or under-conservative design. Hence, many researchers have attempted to evaluate its actual engineering properties through laboratory tests. However, the test results are partially reliable due to the poor core recovery of IGMs and the possible sample disturbance. Subsequently, in-situ tests have been used in recent years to evaluate the engineering properties of IGMs. However, the respective in-situ test finds its limitations while exploring IGMs with different geological formations at deeper depths with the constraints of sampling. Standard Penetration Test (SPT) is the strength-based index test that is often used to explore IGMs. Moreover, it was also observed that the coefficient of variation of the design parameters (which represents the uncertainties in the design parameters) of IGMs is relatively high, and also the studies on the probabilistic characterization of IGMs are limited compared with soils and rocks. With this perspective, the present article reviews the laboratory and in-situ tests used to characterize the IGMs and explores the shear strength variation based on their geological origin.

• 환경생물
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• 제36권3호
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• pp.277-284
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• 2018

In 2017, the freshwater algae were collected from reservoirs, small ponds, soil, and rocks in Korea. Eight taxa of Chlorophyta (Chlorophyceae and Trebouxiophyceae) have been newly reported in Korea. The unrecorded indigenous species were Chlorolobion braunii, Coelastrum pseudomicroporum, Coelastrum reticulatum var. cubanum, Monoraphidium nanum, Tetrachlorella incerta, Ecdysichlamys obliqua, Gloeotila scopulina, and Stichococcus jenerensis.

• Earthquakes and Structures
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• 제13권6호
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• pp.519-529
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• 2017

The surrounding rocks of underground openings are natural materials and their mechanical behavior under seismic load is different from traditional man-made materials. This paper proposes a framework to comprehensively model the mechanical behavior of surrounding rocks. Firstly, the effects of seismic load on the surrounding rocks are summarized. Three mechanical effects and the mechanism, including the strengthening effect, the degradation effect, and the relaxation effect, are detailed, respectively. Then, the framework for modelling the mechanical behavior of surrounding rocks are outlined. The strain-dependent characteristics of rocks under seismic load is considered to model the strengthening effect. The damage concept under cyclic load is introduced to model the degradation effect. The quantitative relationship between the damage coefficient and the relaxation zone is established to model the relaxation effect. The major effects caused by seismic load, in this way, are all considered in the proposed framework. Afterwards, an independently developed 3D dynamic FEM analysis code is adopted to include the algorithms and models of the framework. Finally, the proposed framework is illustrated with its application to an underground opening subjected to earthquake impact. The calculation results and post-earthquake survey conclusions are seen to agree well, indicating the effectiveness of the proposed framework. Based on the numerical calculation results, post-earthquake reinforcement measures are suggested.

• 광물과 암석
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• 제35권3호
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• pp.299-311
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• 2022

지표에 노출된 암석은 지속적으로 풍화를 받게 되고 이러한 영향으로 암석의 공학적 안정성이 약해지게 된다. 특히 풍화가 진행되면서 암석의 표면은 풍화에 의해서 변화를 일으키고 이러한 표면 변화는 암석으로 구성된 지반의 공학적 안전성에 영향을 미치게 된다. 또한, 풍화를 받은 암석에서 생성되는 화학종은 주변환경에 직접적인 영향을 미치거나 구조물에 영향을 미치게 된다. 광산지역과 같이 암석이 노출된 지역에서는 풍화에 의해 생성된 화학종이 주변 자연환경에 심각한 영향을 미치기도 한다. 본 연구에서는 이러한 관점에서 동결/융해 실험을 활용한 풍화가속 실험을 이미 풍화를 받은 암석과 신선한 암석을 대상으로 실시하고 각 암석의 표면 변화를 다초점 레이저 현미경으로 관찰하고 IC/ICP-MS를 활용하여 화학종 생성에 대한 분석을 실시하였다. 풍화가 진행됨에 따라 표면의 거칠기는 완화되는 것을 확인하였고 주변환경에 영향을 미칠 수 있는 화학종은 풍화를 받는동안 양이 증가하는 것을 확인하였다. 본 연구 결과는 암석이 노출된 지역에서의 공학적/환경학적 안전성을 평가하는 기초 자료로 활용될 수 있을 것이다.

• 한국광물학회지
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• 제22권2호
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• pp.163-176
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• 2009

진해지역에 위치하는 납석광상에 대하여, 광산 지질조사를 통해 산출상태를 파악하고, X-선회절분석, X-선형광분석, 전자현미분석, ICP분석 등을 통하여 변질광물의 광물학적 특성을 조사하였다. 그 결과, 이 납석광상에는 일라이트, 딕카이트, 엽납석, 다이어스포어, 녹니석, 황철석, 침철석 등의 다양한 광물들이 산출되었다. 이들 구성광물의 조합을 검토한 결과, A: 석영, B: 석영+ 일라이트, C: 석영 + 일라이트 + 딕카이트, D: 엽납석 + 일라이트 + 딕카이트 + 다이어스포어의 4개 광물조합으로 주로 구분되었다. 이들 광물조합의 산출상태로 보아 규화대, 일라이트변질대, 카올린변질대, 엽납석변질대로 구분할 수 있는 것으로 나타났다. 이 규화대의 대부분은 약 90% 이상의 높은 $SiO_2$ 함량을 보이고 작은 입자의 석영들로만 거의 구성되어 있는 특징을 보였다. 엽납석은 2M형의 폴리타이프에 해당되는 것으로 나타났다. 이 광상의 모암은 유문암질암, 안산암질 응회암 및 화산 각력암 등의 화산암이며, 모암의 차이에 따라 변질대 분포양상이 다소 다르게 나타났다. 이런 화산암이 수소이온 및 실리카의 활동도가 높은 산성열수용액에 의해 변질작용을 받아 납석광상이 형성되었으며, 그중에서 엽납석변질대가 가장 고온의 환경에서 생성된 것으로 사료된다.