• The Journal of Engineering Geology
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• v.12 no.3
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• pp.295-303
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• 2002

The stability of rock slopes is closely related to the factors such as: type of rock, development of geological structures, weathering, characteristics of rock, and the shape of the geological features. When we design the rock slope, the slope stability is determined by the discontinuity causing the circular, plane or wedge failure. The failure happens when the slope is under the unstable geological condition. But in some cases, slope failure has occurred even though the slope is under stable geological conditions. In this respect, this paper presents the plane failure conditions for domestic rock slopes through research of sites where slope failure has occurred regardless of whether or not it satisfied the stable geological conditions.

• Tunnel and Underground Space
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• v.30 no.4
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• pp.417-431
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• 2020

In this study, a fundamental investigation was made on how to use LiDAR technology to determine the degree of weathering and alteration of rock mass. The purpose of the study was to identify the affecting parameters to LiDAR intensity and to quantitatively assess the relations among them through laboratory-scale experiment. A few potential affecting parameters were selected including scanning distance, incidence angle, surface roughness, surface color, mineral composition, and water saturation. In the experiment, FARO LiDAR unit was used for twelve different types of specimen. It was observed that the intensity was affected by, in the order of importance, surface color, incidence angle, scanning distance, property of rock, water condition, and surface roughness.

• The Journal of Engineering Geology
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• v.19 no.1
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• pp.1-8
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• 2009

Geophysical surveys were conducted on an upper part of a natural slope located at Daejeon University. Electrical resistivity and seismic refraction measurements were carried out to obtain information on a weathered zone and internal structure at shallow depth, while AMT measurement a bed rock and geological structure at deep depth. With all the techniques applied, these results show a good correlation between electrical resistivity images and refraction velocity distributions for the characterization of a weathering and geological structure at depth. In particular, AMT survey seems to be the powerful tool for detecting a distribution of a bed rock with deep depth. The combined geophysical investigation produced a detailed image of a subsurface structure and improved well in the interpretation.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.966-973
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• 2008

In recent, the collapses of cut-slope is gradually increased due to the heavy rains accompanied by typhoon. Specially, many cut-slope failures and landslides was happened to Goheung, Yeosu, Suncheon region, Jeonranamdo in the middle of September 2007. The slope of investigation is width 20 m, height 22 m, and the circular failure was occurred. The parent rocks of the slope are pyroclastic rock, namely andesite, andesitic tuff et al. and the weathering grade is completely weathered to residual soils owing to rapid weathering process and has the existence of fault zone and mafic dyke. Also, lots of extension cracks are presented and the hydrologic condition is very deteriorated. As a result of the limit equilibrium analysis, the safety factor is 1.09(in dry season) and 0.64(in wet season). For the stabilization of the cut-slope, we decided to use the retaining wall, anchors and drainage apparatus.

• 보존과학연구
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• s.16
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• pp.123-128
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• 1995

For establishing the plan of scientific conservation on the Kyongch′onsa and site of Won-gaksa 10 floors pagodas, the investigation on the rocks consisting these pagodas has been made on the rock phase and weathering characteristics. The Kyongch′onsa pagoda consists of fine grained pale graylimestone containing abundant fossils of shell and fragments of organisms. The site of Won-gaksa pagoda is composed of marble of pale gray, white and/or light brown color, which is intercalated with thin mica schist. The marble, the recrystallized limestone, consists mainly of recrystallized calcite accompanied with minor amount of muscovite. Especially carbonate rocks are somewhat different in chemical weathering from such granitic rocks. The field survey and laboratory experiment using polarizing microscope had been done during 30 days from Feb, 13 to March, 31, 1995. The rocks equivalent to that of the site of Kyongch′onsa were identified from the Myobong limestone formation and taken samples around the road from P′yongch′ang to Mitan, P′yongch′ang-gun. The rocks similar to that of the site of Won-gaksa pagoda were distributed around Pan-un-ri, Chunch′on-myon, Yong-wol-gun. The rocks of the Silluksa pagoda consisting of white recrystallized limestone with banded structure are similar to the marble of the Hyangsan-riformation distributed around Suanbo, Ch′ungch′ongbuk-do.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.67-76
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• 2009

Statistical analysis was performed using a series of data on RMR, RMR* and crown settlements collected from sites of weathering rock tunnels in Korea. The crown settlements were predicted by recurrence analysis, exponential function, and artificial neural network (ANN) using collected in-situ data. The result of the prediction fitted well compared to the measured settlement in the order of ANN, exponential function, and recurrence analysis. The range of crown settlement predicted by recurrence analysis widely scattered and promised larger settlement than the measured. Also in all method, the predicted value by RMR well matched compared to the measured settlement predicted by RMR*.

• Journal of The Geomorphological Association of Korea
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• v.18 no.1
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• pp.57-71
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• 2011

Granitic regolith profile in Goseong, southern Korea, reveals various types of corestones from unweathered round fresh rocks to decomposed rock cores with unweathered spheroidal rock-layers on outer surface, deep weathering profile with 10m in depth, and red saprolite usually cited as related to high temperature climatic environment. In respect of this optical features such as the depth and the color of the profile, Goseong granitic profile may be regarded as products of paleoclimate with more high temperature and humidity than the present. But it is revealed that halloysite is a predominant clay mineral in upper part as well as lower part by XRD analysis. Halloysite is dominant mineral in hydrothermal alteration milieu. The leaching rate of chemical components is up to 97%, very high compared to common granite profiles with 60~70% in Korean peninsula. So, it is assumed that granitic red regolith in Goseong is a product of hydrothermal alteration, not meteoric weathering.

• Economic and Environmental Geology
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• v.48 no.2
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• pp.131-145
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• 2015

Thermodynamic prediction of weathering products from primary aquifer minerals around underground disposal sites was investigated. The distribution of solubility quotients for kaolinite-smectite reactions showed the trend of reaching at equilibrium with Ca-, Mg-, and Na-smectite for deep groundwaters in granitic aquifers. The values of $10^{-14.56}$, $10^{-15.73}$, and $10^{-7.76}$ were proposed as equilibrium constants between kaolinite and Ca-, Mg-, and Na-smectite end members, respectively. On stability diagrams, most of deep groundwaters were located at equilibrium boundaries between stability fields of kaolinite and smectites or on stability fields of smectites and illite. Shallow groundwaters in basic rock aquifer were plotted at the same stability areas of deep granitic groundwaters on stability diagrams. The results indicated that the primiary mineralogical composition may be important to predict weathering products in deep aquifers.

• 보존과학연구
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• s.25
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• pp.171-195
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• 2004

This research presents an evaluation of the weathering and deterioration state of the Wanggung-ri five-storied stone pagoda in the Iksan (National Treasure No. 289) and suggests conservational schemes. A deterioration map of the pagoda was drawn from the aspects of petrological, physical, chemical, biological, structural and artificial weathering.The rock properties consisting of the pagoda were medium-grained biotite granite that had leucocratic phenocryst developed in parts. The body of each story suffered severely from the secondary contamination that turned the colors into light grey, pitch dark, yellowish brown, and reddish brown as well as granular decomposition, exfoliation and peel-off. The roof stones were heavy exfoliated or peeled off in most of the cases. In addition to the fine cracks, there were layered cracks on the corners. The roof stones of the3rd and 4th story in the north and west side had some stones fall-off, while those of the 2ndstory in the north side had steel reinforcement filled for a fixing purpose. Those of the 5th story showed big gaps that must have originated from cracks and were easily subject to granular decomposition and rainfall. The inside clay filler was missing in the lower part of the roof stones of the 4th and 5th story and the supporting stones, which were thus covered by light grey or pitch dark sediments. The contact area of the materials was about 70 % in the parts where there was a space due to the filler missing and washigher than 90 % in the lower parts of the pagoda. About 90 % or more of the roof stones surface of each story were covered by aerial plants that formed a thick biological mat. Thus it seemed necessary to come up with the conservational measures to remove the plans living on the surface of the stone materials, with the plans to prevent rain from falling inside, and with the water repellent and hardening treatments to postpone the surface weathering of the rock properties. All those measures and plans must be based on the results of long-term monitoring and thorough detail investigations.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.552-560
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• 2017

This study investigates the development process of Mt. Deok on Bigeum Island, Shinan, on the basis of geomorphological and geological analyses. K-Ar dating was carried out on two samples of the acidic lapilli tuff developed in the study area, and the obtained K-Ar ages are $70.4{\pm}1.4$ and $76.9{\pm}1.5Ma$, which correspond to the Late Cretaceous (Campanian). Mt. Deok is surrounded by rock cliff, and various weathering microtopographic features, such as tafoni, tor and gnamma, are developed. Tafoni with diverse morphologic types is the most dominant feature, indicative of intense salt weathering. Geological characteristics such as porous tuff and joint have played an important role in the development of tafoni and rock cliff. Geomorphology and geology of Mt. Deok reflect paleoenvironmental change and interaction between human and nature in the coastal area.