• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.9
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• pp.1452-1461
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• 1997

The hot press apparatus to obtain the solidified rocks with 60mm of diameter against rock waste was developed, and the optimum conditions for solidification were founded out, of which were 300.deg. C of temperature and 1hr of holding time. The solidified rocks reinforced with the fibers (carbon, steel) were made by means of a hydrothermal hot press method. Fracture toughness of those was obtained using the round compact tension(RCT) specimens. Load and displacement behaviours of the solidified rocks reinforced with the fibers were dependent upon the fiber volume fraction and kind of the fibers. Strength and fracture energy of the solidified rocks with steel were much larger than those of the solidified ones with carbon because of the Bridge's effect, multiple cracking and crack branching phenomena.

• Geomechanics and Engineering
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• v.16 no.3
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• pp.273-284
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• 2018

A detailed understanding of the mechanical behaviors for crushed coal rocks after grouting is a key for construction in the broken zones of mining engineering. In this research, experiments of grouting into the crushed coal rock using independently developed test equipment for solving the problem of sampling of crushed coal rocks have been carried out. The application of uniaxial compression was used to approximately simulate the ground stress in real engineering. In combination with the analysis of crack evolution and failure modes for the grouted specimens, the influences of different crushed degrees of coal rock (CDCR) and solidified grout strength (SGS) on the mechanical behavior of grouted specimens under uniaxial compression were investigated. The research demonstrated that first, the UCS of grouted specimens decreased with the decrease in the CDCR at constant SGS (except for the SGS of 12.3 MPa). However, the UCS of grouted specimens for constant CDCR increased when the SGS increased; optimum solidification strengths for grouts between 19.3 and 23.0 MPa were obtained. The elastic moduli of the grouted specimens with different CDCR generally increased with increasing SGS, and the peak axial strain showed a slightly nonlinear decrease with increasing SGS. The supporting effect of the skeleton structure produced by the solidified grouts was increasingly obvious with increasing CDCR and SGS. The possible evolution of internal cracks for the grouted specimens was classified into three stages: (1) cracks initiating along the interfaces between the coal blocks and solidified grouts; (2) cracks initiating and propagating in coal blocks; and (3) cracks continually propagating successively in the interfaces, the coal blocks, and the solidified grouts near the coal blocks. Finally, after the propagation and coalescence of internal cracks through the entire specimens, there were two main failure modes for the failed grouted specimens. These modes included the inclined shear failure occurring in the more crushed coal rock and the splitting failure occurring in the less crushed coal rock. Both modes were different from the single failure mode along the fissure for the fractured coal rock after grouting solidification. However, compared to the brittle failure of intact coal rock, grouting into the different crushed degree coal rocks resulted in ductile deformation after the peak strength for the grouted specimens was attained.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1524-1533
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• 2021

The structural stability of a waste package is essential for containing radioactive waste for the long term in a repository. A silo-type disposal facility would require more severe verification for the structural integrity, because of radioactive waste packages staked with several tens of meters and overburdens of crushed rocks and shotcretes. In this study, structural safety was analyzed for a silo-type repository, located approximately 100 m below sea level in Gyeongju, Korea. Finite element simulation was performed to investigate the influence of the loads from the backfilling materials and waste package stacks on the mechanical stress of the disposed of wastes and containers. It was identified that the current design of the waste package and the compressive strength criterion for the solidified waste would not be enough to maintain structural stability. Therefore, an enhanced criterion for the compressive strength of the solidified waste and several reinforced structural designs for the disposal concrete container were proposed to prevent failure of the waste package based on the results of parametric studies.

• The Journal of the Petrological Society of Korea
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• v.5 no.1
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• pp.35-51
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• 1996

The granitic rocks in the vicinity of the Mt. Sorak, the northeastern part of the NE-SW elongated Mesozoic granitic batholith in the Kyeonggi massif, consist of granodiorite, biotite granite, two-mica granite and alkali feldspar granite. Variations In major and most trace elemental abundances show a typical differentiation trend in a granitic magma. Granitic rocks all display a calc-alkaline trend in the AFM diagram. Also, In the ACF diagram discriminating between I- and S-type granitic rocks, granodiorite and most biotite granite in the southeastern area represent I-type and magnetite-series characteristics, while most biotire granite and two-mica granite in the northwestern area exhibit S-type and ilmenite-series ones.According to recent studies of the granitle rocks In the Inje-Hongcheon district. all ihe granitic rocks distributed in the northeastern part of the Kyeonggi massif have been classified as late Triassic to early Jurassic Daebo granite. With reference of the formerly published ages, an age oi $125.6{\pm}4.4$ Ma calculated by the slope in the plot of $^{87}Rb/^{86}Sr-^{87}Sr/^{86}Sr$ for the biotite granite samples from the southeastern area is inferred as an emplacement age for the granitic rocks in the vicinity of the Mt. Sorak. On the basis of elemental variations and Sr isotope compositions, an possible evolutional process for the granitic magmas in this area is suggested. The primary magma of I-type and magnetite-series generated about 125 Ma by partial melting of igneous originated crustal materials, might be emplaced and evolved through fractional crystallization, convection and assimilation of the surrounding Precambrian metasediments to become S-type and ilmenlte-serles in the outer area, and then solidified to granodiorite, biotite granite and two-mica granite.At the latest stage, the evolved hydrothermal solution altered the formerly solidified biotite granite to alkali feldspar granite and probably later local igneous activities affected the alkali feldspar granite again.

• The Journal of the Petrological Society of Korea
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• v.3 no.3
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• pp.220-233
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• 1994

The granitic rocks in the Poeun - Sogrisan area are composed of the Jurassic Poeun granodiorite and the Cretaceous Sogrisan granites. The latter can be divided into three rock types : coarse-grained biotite granite, porphritic biotite granite and granite porphyry. Petrographical observations, especially focusing on the quartz-feldspar intergrowth texture, suggest that the Sogrisan granites has emplaced at shallower level and crystallized more rapidly than the Poeun granodiorite. The F, Cl contents and the Fe/(Fe+Mg) ratio of biotite and muscovite in the Sogrisan granites are higher than those in the Poeun granodiorite. The anor-thite contents of plagioclase in the Poeun granodiorite are higher then in the Sogrisan granites. Ilmenite in the Sogrisan granites is more enriched in Mn and depleted in Fe than that in the Poeun granodiorite. The whole-rock magnetic susceptibility values (in $10^{-6}$ emu/g unit) are higher in the Sogrisan granites (33~144) than the Poeun granodiorite (9~12), indicating that the former generally belongs to magnetite-series granitoid and the latter to ilmenite-series one. The Sogrisan granites has solidified under more oxidizing environment than the Poeun gra-nodiorite, judging from the whole-rock magnetic susceptibility measurements as well as the chemical compositions of biotite and ilmenite.

• Journal of the Korean Society of Industry Convergence
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• v.14 no.1
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• pp.1-7
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• 2011

Basalt originates from volcanic magma and flood volcanoes, a very hot fluid or semifluid material under the earth's crust, solidified in the open air. Basalt is a common term used for a variety of volcanic rocks, which are gray, dark in colour, formed from the molten lava after solidification. Recently, attention has been devoted to continuous basalt fibers (CBF) whose primary advantage consists in their low cost, good resistance to acids and solvents, and good thermal stability. In order to investigate reinforcement effect, this paper did FEM analysis with shell element. The result were as follows; BCF deck plate did elastic behavior to 450 kN, reinforcement effect of basalt fiber (BF) was less. But BCF's perpendicular deflection occurred little about 23 mm comparing with RC deck plate in load 627 kN. Stiffness was very improved by basalt fiber reinforcement.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.113-127
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• 2005

Cretaceous intrusive and extrusive rocks are widely distributed in the southwestern part of the Korean peninsula, possibly the result of intensive magmatism which occurred in response to subduction of the western proto-Pacific plate beneath the north-eastern part of the Eurasian plate. Geochemical and petrological study on the Cretaceous granitic rocks were carried out in order to constrain the petrogenesis of the granitic magma and to establish the paleotectonic environment of the area. Whole rock chemical data of the granitic rocks from the study area indicate that the all the rocks have characteristics of calc-alkaline series in the subalkaline field. The overall geochemical features show systematic variations in each granitic body, but the source materials of each granitic body are thought to have been different in their chemical composition. Higher values of $Fe_2O_3/FeO$ of the granitic rocks in the western area suggest that the granitoids had been solidified under highly oxidizing environment. The granitic bodies in the eastern area also show higher contents of Li, Ni, Co, Sr, Cr, Sc and lower Rb and Nb compared to the those of the western area. Chondrite normalized REE patterns show generally enriched LREE and strong negative Eu anomalies in the western wet while slight to flat Eu anomalies in the east-ern area. The REE and $(La/Lu)_{CN}$ of the granites are $60{\~}499ppm$ and $8.9{\~}66$ correspond to the range of the continental margin granite. On the ANK vs. ACNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type, VAG and syn-collision granite. Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at continental margin during the subduction of proto-Pacific plate.

• The Journal of the Petrological Society of Korea
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• v.6 no.3
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• pp.185-209
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• 1997

Granitic rocks in the Cheongsan area cosist of three plutons-Baegrog granodiorite, Cheongsan porphyritic granite, and two mica granite. Amphilboles from the Baegrog granodiorite belong to the calcic amphilbole group and show compositional variations from magnesio-hornblende in the core to actinolitic hornblende in the rim. Biotites from the three granites represent intermediate compositions between phlogopite and annite. Muscovites from the two mica granite are considered to be primary muscovite in terms of the occurrence and mineral chemistry. Each granitic rock reveals systematic variation of major oxide contents with $SiO_2$. Major oxide variation trends of the Baegrog granodiorite are fairly different from those of Cheongsan porphyritic granite and two mica granite. The latter two granitic rocks are also different with each other in variation trends for some oxides. Thus three granitic rocks in the Cheongsan area were solidifield from the independent magmas of chemically different, heterogeneous origin. The granitic rocks in the area show calc-alkaline nature. The whole rock geochemistry shows that the Baegrog granodiorite and Cheongsan porphyritic granite belong to metaluminous, I-type granite, whereas the two mica granite to peraluminous, I/S-type granite. The opaque mineral contents and magnetic susceptibility represent that the granitic rocks in the area are ilmenite-series granite, indicating that each magma was solidified under relatively reducing environment. The tectonic environment of the granitic activity in the area seems to have been active continental margin. Alkali feldspar megacryst in the Cheongsan porphyritic granite is considered to be magmatic, judging from the crystal size, shape, arrangement, and distribution pattern of inclusions. The petro-graphical characteristics of the Cheongsan porphyritic granite can be explained by two stage crystallization. Under the smaller degree of undercooling the alkali feldspar megacrysts rapidly grew owing to slow rate of nucleation and fast growth rate. At the larger degree of undercooling the nucleation rate and density drastically increased and the small crystals of the matrix were formed.

• Tunnel and Underground Space
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• v.26 no.4
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• pp.266-273
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• 2016

We have numerically modeled thermal evolution of Ulleung Island after an emplacement of magma chamber. The disk-shape magma chamber is assumed to locate at 2.9 km beneath the island and has a diameter and a thickness of 10 km and 300 (or 600) m, respectively. The geothermal gradients evaluated from the numerical modeling coincide well with the range of the geotherms (${\sim}95^{\circ}C/km$) observed from the well logging. Although there are limitations in the application of the numerical results directly to the interpretation of the observed geotherms, we believe that an existence of a hot magma chamber in molten or in solidified state is the most plausible explanation for the observed geotherms.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.200-213
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• 2002

The Andong granitoid batholith represents five temporally distinct episodes (phases) of igneous activity. The batholith represents a plutonic complex of five pulsatively emplaced distinct intrusive multiphases. The petrochemical data show that the plutons fall into calc-alkaline series except for the Yean pluton, and plot within the diaenostic range for I-type origin and continental arc orogenic tectonic setting. Each pluton reveals systematic compositional variations of major and trace elements with $SiO_2$ or MgO, but different variation trends for some elements and considerably different REE patterns. Thus discontinuous, inconsistent variations in the elements indicate that the five plutons can not be explained by simple fractional crystallization from the same primary magma, but were intruded and solidified from the independent magmas of chemically heterogeneous origin. In the Andong, Dosan and Pungsan plutons, high values of molar CaO/(MgO+$FeO^{t}$ ) combined with low $Al_2$$O_3$/(MgO+$FeO^{t}$ ) and $K_2$O$Na_2$O ratios suggest a magma originated by dehydration melting of a metabasaltic to metatonalitic protolith. Whereas the Imha pluton show similar values of CaO/(MgO+$FeO^{t}$ ), but significantly higher ratios of $Al_2$$O_3$/(MgO+$FeO^{t}$ ) and $K_2$O$Na_2$O implying to a metagreywacke protolith.