• The Journal of Engineering Geology
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• 제20권4호
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• pp.461-465
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• 2010

Weathering and permeability in rocks play a very important role in underground disposal of radioactive waste and their long-term management as well as stability security of rock structures. Weathering and permeability of rocks are largely controlled by the characters of inner structures of rocks. In other words, weathering rate can be accelerated depending on the quantity of pore and microcrack in rocks. Quantitative evaluation of inner structures of rocks can serve as a tool that can assess the degree of weathering of rocks. Therefore it can be said that the understanding of three dimensional distribution of the inner structure of rocks is important for long-term management of rock structures. This study was performed to analyze three dimensional distribution of pore in rocks using Micro Focus X-ray CT on fresh granite and weathered granite from Korea. Results of the analysis clearly show distribution of pore and porosity of the inner rock.

• Proceedings of the Petrological Society of Korea Conference
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• 한국암석회.한국광물학회 2009년도 공동학술발표회 논문집
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• pp.53-55
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• 2009

• Tunnel and Underground Space
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• 제29권6호
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• pp.542-557
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• 2019

The behavior of rock mass is influenced by its microscopic feature of internal structure generating from forming and metamorphic process. This study investigated a new methodology for characterization of rock based on the X-ray CT (computed tomography) images reflecting the spatial distribution characteristics of internal constituent materials. The X-ray image based analysis is capable of quantification of heterogeneity and anisotropy of rock fabric, size distribution and shape parameter analysis of rock mineral grains, fluid flow simulation based on pore geometry image and roughness evaluation of unexposed joint surface which are hardly acquired by conventional rock testing methods.

• Tunnel and Underground Space
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• 제27권5호
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• pp.333-342
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• 2017

In this study, the heterogeneity of internal structure of various igneous rocks acquired in Korea was quantified and correlated with the seismic velocity and the point load strength. Three-dimensional X-ray Computed Tomography (CT) was used to obtain information on the internal structure of the rock specimen, and the representative unit length (LR) was calculated by applying a statistical technique to the CT images. We also proposed an estimation equation to predict the mechanical properties of rocks from the relationship between LR, acoustic velocity and point load strength. In the proposed method, it is shown that the characterization of internal structure of rocks could be utilized as an indirect index to account for the mechanical behavior of rocks by substituting physical laboratory testing for non-destructive test.

• The Journal of the Petrological Society of Korea
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• 제23권2호
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• pp.139-144
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• 2014

A series of the planar cathodoluminescence (CL) and backscattered-electron (BSE) images of magmatic zircon from the Paleozoic Yeongdeok pluton in the southeastern Korean Peninsula were taken using a scanning electron microscope for a 3D reconstruction of internal zonation of zircon. Seven zircon crystals mounted in epoxy were serially polished with average $3{\mu}m$ thickness to their disappearance. Their 3D reconstruction of zonation was performed using the Volume Viewer function in the ImageJ software. The 3D oscillatory zoning pattern of zircon was apparently shown in all the analyzed crystals. This method can further be applied to zircon crystals of multiple growth histories as well as other geological materials.

• Journal of the Speleological Society of Korea
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• 제88호
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• pp.51-62
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• 2008

동굴내부의 지형변형은 동굴내의 외인적인 요인과 내인적인 요인에 의하여 발달된다. 외인적인 요인으로서 기후변동에 의한 기온의 변화와 침출수의 증감 및 외부 이입물질 등을 들 수 있으며, 내인적인 요인으로서는 암석의 공극율, 지질환경, 단층 및 습곡면의 형상, 절리 및 균열면의 유무, 동굴지천의 구배 및 유속, 층리간의 이종의 암석게재 여부 등을 들 수 있다. 동굴 시스템은 수문 물리화학적 요소에 의해 형성되며 외부 기준면 통제에 의해서 암석학, 구조학, 기후학, 생물학, 토양학 등과 밀접한 상태에서 의존적인 발달 과정을 가진다. 동혈 내부의 침식은 유수의 입력 경우 유출과정에서 형성되며, 또한 유수의 비 입력 경우유출 및 액체용액의 분출에 의해서 형성된다. 다수의 동굴학자들은 동굴은 계절마다 침수되거나 빨리 흐르는 홍수에 의한 폭우에 의해 epiphreatic 상태에서 간헐적으로 포화되는 과정을 거치며 선택적으로 발달한다고 주장하고 있다. 혼합지대 동굴의 가장 좋은 예는 현재의 카르스트 지역에서 나타나는 것이 아니라 과거 제4기의 200만년전 동안보다 해수면이 더 안정적이었던 때에 이루어진 고 카르스트(Paleo Karst)에서 발견되고 있다.

• Journal of the Korean Geotechnical Society
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• 제36권9호
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• pp.45-55
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• 2020

X-ray computed tomography (CT) is very useful for the quantitative evaluation of internal structures, particularly defects in rock samples, such as pores and fractures. In situ CT allows 3D imaging of a sample subjected to various external treatments such as loading and therefore enables observation of changes that occur during the loading process. We reviewed state-of-the-art of in situ CT applications for geomaterials. Two triaxial cells made using relatively low density but high strength materials were developed aimed at in situ CT scanning during hydro-mechanical laboratory testing of rocks. Preliminary results for in situ CT imaging of granite and sandstone samples with diameters ranging from 25 mm to 50 mm show a resolution range of 34~105 ㎛ per pixel pitch, indicating the feasibility of in situ CT observations for internal structural changes in rocks at the micrometer scale. Potassium iodide solution was found to improve the image contrast, and can be used as an injection fluid for hydro-mechanical testing combined with in situ CT scanning.

• Korean Journal of Mineralogy and Petrology
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• 제33권3호
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• pp.259-272
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• 2020

The seismic properties in the crust are affected by the lattice preferred orientation(LPO) of major minerals in the crust. Therefore, in order to understand the internal structure of the crust using seismic data, information on the LPO of the major constituent minerals and the seismic properties of major rocks in a specific region are needed. However, there is little research on the LPOs of minerals in the crust in Korea. In this study, we collected amphibolites from two outcrops in Wigokri, Gapyeong, located in the nothern portion of Gyeonggi Massif, and we measured the LPOs of major minerals of amphibolite, especially amphibole and plagioclase through EBSD analysis, and calculated seismic properties of amphibolite. Two types of LPOs of amphibole, which are defined as type I and type IV, were observed in the two outcrops of Gapyeong amphibolites, respectively. In the case of amphibolites with the type I LPO of amphibole, large seismic anisotropy of both P- and S-wave was observed, while in the amphibolites with the type IV LPO of amphibole, small seismic anisotropy was observed. This is consistent with previous experimental results. The polarization direction of the fast S-wave was aligned subparallel to the lineation regardless of the LPO types of amphibole. The seismic anisotropy observed in Gapyeong is expected to be helpful to interpret the structure and seismic data within the crust in Gyeonggi Massif.

• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2004년도 제19회 발표논문집
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• pp.78-91
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• 2004

염(Salts)은 일반적으로 가장 강력한 풍화요인 물질 중 하나이다. 염의 결정화(crystallization) 및 수화(hydration)작용은 석재의 화학적 풍화 뿐만이 아니라 물리적 풍화를 가속화 시킨다. 감은사지 석탑은 오랜 세월 대기 중에 노출되어 대기환경오염으로 인한 화학적 풍화 뿐만이 아니라 지리적으로 바다에 인접해 있어 바다에서 기원한 염화나트륨(NaCl)의 영향으로 다른 석조물에 비해 심한 물리적 풍화현상을 보이고 있다. 편광 현미경 및 SEM, XRD, XRF를 이용하여 석탑의 구성석재 및 염(salts)에 대한분석을 실시하였으며, 용출실험을 통해 얻은 용액에 대해서는 IC와 ICP-AES를 이용하여 분석하였고, 염류와 석재의 반응산물로 만들어진 염에 대해서는 정방위시료와 부정방위시료를 제작하여 분석하였다. 감은사지 석탑을 이루는 암석은 결정응회암으로 주 구성 광물은 사장석 및 정장석이며 소량의 석영 및 흑운모 등이 함유되어 있고 소량의 유리질 석기로 구성되어 있다. 석재의 표면에는 주 구성 광물들의 화학적 풍화로 인해서 생성된 2차 광물로 팽창성 점토광물인 스멕타이트가 존재하며, 대기오염물질과의 결합에 의해 생성된 대표적인 황산염인 석고$(gypsum,\;CaSO_4{\cdot}2H_2O)$, 소금(halite, NaCl), 해양기원 염류인 소금성분과 대기오염물질이 만들어낸 테나다이트$(thenardite,\;Na_2SO_4)$가 존재한다. 이들 염류는 일차적으로 암석의 표면에 백화현상을 초래하기도 하고, 대기 중의 오염물질과 결합하여 일부는 흑화현상을 보이기도 한다. 또한 암석 내 수분이 증가할 경우 이들 염들이 암석의 공극이나 열극을 따라 내부로 이동하여 subflorescence를 발생시켜 박락 및 박탈의 원인이 되었으며, 온도와 수분의 변화에 따른 이들 염(salts)의 수화 및 결정 작용 그리고 새로운 염(salts)의 침전작용을 반복하면서 석재 내부와 외부의 암석 및 결정에 균열과 미세열극 등이 생성되어 석재 자체의 구조적 안정성에 영향을 주고 있다. 따라서 감은사지 석탑은 지리적 환경 차이로 인해 일반적인 환경의 석조물들과는 다른 형태의 풍화양상을 보이고 있어서 풍화양상 및 풍화형태에 대한 정확한 연구와 이해를 바탕으로 보존대책이 마련되어야 한다.

• The Journal of the Petrological Society of Korea
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• 제10권3호
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• pp.212-221
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• 2001

This paper introduces the characteristics and generation of the synchrotron radiation (SR). SR has the very high spectral brilliance, broad spectral range, X-ray wavelength tunability, high degree of polarization and collimation, and pulsed time structure. Also describes the technologies to apply in the fields of geology and environmental sciences. These include X-ray tomography, XRF, EXAFS, XANES, DAC, IVP experiments. Further, nuclear power generation and nuclear waste disposal methods are mentioned relating to energy. Using these, analyses of the chemistry, crystal structure and chemical combining states of minerals and rocks can be carried out. Applications in the fields of the economic geology, paleontology and environmental sciences are open too. Informations of the Earth interior materials' behavior under high pressure-temperature can be acquired.