• Geotechnical Engineering
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• v.14 no.5
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• pp.53-66
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• 1998

Since weathered soils are made by weathering process, the characteristics of weathered soils are strongly related to the originated rock and its forming process. Investigations on the originated rock and the weathering environments that decide the forming process are indispensable for the appropriate analysis on weathered soils. In this study, forming process of weathered soil is investigated by geological viewpoint. Test results show that weathering of rock is closely related to the distribution of rock-forming mineral and forming process. Weathered granite soils have the isotropic in-situ stress state and shearing behavior caused by the non-directional characteristics of originated rock. And weathered gneiss soils have the directional characteristics that mechanical behavior is determined by internal discontinuities. It it proved that the weathering resistance of Quarte is greater than that of feldspar and mica, and it is concluded that the thickness of weathered region is greatly influenced by the distribution of rock-forming mineral.

• Journal of Conservation Science
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• v.5 no.1 s.5
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• pp.41-68
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• 1996

Stone-cultural-properties, distributed In the area, have been investigated and studied on the characteristics and the rock phases in the geological and conservational point of view. Stone-Buddhas in the area can be subdivided into Maebul-, General -, and Massive rock-types according to their styles. The rocks used in these stone-cultural-properties are mainly massive, coarse grained biotite granite of the Jurassic age, which is widely distributed around the Reckon-gun area. However, quartz-feldspathic banded gneiss, marble, phyllite and hornblendite are also used. These rocks are mainly distributed in the Yongin-gun area. This suggests that the rocks used. These rocks are strongly influenced by chemical weathering so that the rock surface is very irregular with $2\~3mm$ relief. Biotite granite used shows generally weathered surface of brown color due to chemical weathering of feldspars. Moss are pervasive partly on the surface to show black and/or green colors. The strong weathering may induce secondarily to appear the igneous lineation, onion-structure, and/or minor cracks latent in the rocks. The cultural properties In the area are relatively well conserved except Maebuls and one(Duchangri 3-story) pagoda. However, one stone-buddha may be grinded recently by machine to take off the weathered surface resulting in the loss of its age and the original detailed shape. For conservation, they must be scientifically considered on the shape, kind of the rock phase and characteristics of the weathered phenomena.

• Tunnel and Underground Space
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• v.25 no.3
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• pp.231-243
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• 2015

In this study, both in-situ stress measurements and a lot of laboratory rock tests were conducted at a metal mine in Jeongseon, Korea. The stress ratio obtained from in-situ stress measurements showed a tendency to decrease according to depth below surface and its average value was 1.10. The mechanical properties such as unit weight, absorption ratio, porosity, elastic wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, shore hardness, friction angle and cohesion were investigated for the four different rocks mainly distributed at a studied mine, which were dolomite, felsite, granite and magnetite. The mechanical properties of the four different rocks were compared by means of statistical analyses, whereupon the felsite and the granite turned out to have more strength characteristics than the magnetite. The correlation of mechanical properties was also investigated, whereupon a few results against the general correlation were found out. The failure criteria of the four different rocks were finally discussed by means of both Mohr-Coulomb criterion and Hoek-Brown criterion.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.271-281
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• 2013

Freeze-thaw experiments were conducted to evaluate changes in surface roughness and physical properties in samples of granite from Ilgwang and Imki mines, Korea. The temperature range in the experiments was $-20^{\circ}C$ to $40^{\circ}C$, based on typical summer and winter temperatures in Korea, and the surface was observed every 20 cycles. One cycle comprised 1 hour of heating or cooling of the samples and 1 hour during which the target temperature was maintained. With increasing repetitions of the freeze-thaw experiment, porosity increased by 0.05%-0.15% in the two samples and the dry weight increased, whereas the volume of the soil and saturation weight decreased. Observations by confocal laser scanning microscope (CLSM) revealed that line and surface roughness parameters showed a tendency to increase and decrease, respectively, with elapsed time. Changes in surface roughness were apparent on the CLSM images.

• Journal of Conservation Science
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• v.29 no.4
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• pp.321-332
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• 2013

Namwon Singyeri Maaeyeoraejwasang (Rock-Carved Seated Buddha Statue) is composed mainly foliated granite and is different metamorphic grade and weathering degree on rock location. As the results of deterioration evaluation, upper part of the buddha statue was estimated that granularity decomposition was serious and rock strength was lower than lower part. Furthermore organism assessed most effect of among weathering factors. Chl. a amount of organism species were calculated $0.2{\mu}g/cm^2$ of crustaceous lichen, $1.1{\mu}g/cm^2$ of foliose lichen, $2.3{\mu}g/cm^2$ of bryophyte. Organism was taken treatment in order of amount of Chl. a and pre-cleaning, dry cleaning, wet cleaning in sequence. It should be establish conservation plan that strengthening in consideration of lithology characteristics and setting in good condition environment to conserve long-term of Maaeyeoraejwasang.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.225-234
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• 2004

The Chungung-dong 5-storied pagoda (Treasure No. 12) in the nnm, Korea was studied on the basis of petrological weathering and deterioration diagnosis. Frontal part of the pagoda is looked out on the N30$^{\circ}$W. Constitution rocks of this pagoda show augen gneiss and biotite granite. Host rock of the pagoda was highly exfoliation and discoloration, therefore most rock-forming minerals were altered to the clay minerals due to the mineralogical and chemical weathering. Open cavity and rock surface occur partly green and black patchs because of contamination by algae, lichen and moss, and the lower part of the pagoda is transition to the some weeds. This biological problems are need for cleaning and chemical treatments. For the structural stability, the pagoda is rebuilt without open gap between the each rock materials. All iron plates eliminate from the difference gap of the rock materials, and properly conservation treatments need to be repaired petro-filler for stone cultural properties and water curtain for the humidity attenuation of the ground.

• Economic and Environmental Geology
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• v.30 no.4
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• pp.353-362
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• 1997

P wave velocities of core samples from the Pocheon granite were measured before and after applications of cyclic loading. Then. distribution of the pre-existing microcracks and microcracks developed due to the cyclic loading was investigated by analyzing P wave velocity anisotropies and microscopic observations from thin sections. Anisotropy constants were calculated with three different ways: (1) $C_A$ between the maximum and the minimum velocities, (2) $C_AI$ between velocities measured along the axial direction and the average of six velocities measured in the planes perpendicular to the loading axis (rift plane) and (3) $C_AII$ between the maximum and the minimum velocities measured in the plane perpendicular to the loading axis. Among anisotropy constants. $C_AI$ was the most effective anisotropy constant to identify the rift plane whose orientation is parallel to the pre-existing microcracks as well as the distribution of stress induced microcracks. $C_AI$ decreased after cyclic loading and the relationship between $C_AI$ and number of cycles shows comparatively coherent negative trends. indicating that stress induced microcracks are aligned perpendicular to the orientation of pre-existing microcracks and that the amounts are proportional to the number of loading cycles. The difference of anisotropy constants before and after cyclic loading was effective in delineating the level of cracks and we called it Induced Crack Index. Velocity measurements and microscopic observations show that anisotropy was caused mainly due to microcracks aligned to a particular direction.

• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.475-486
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• 2005

According to the inference results of formation process of the tectonic lineament, totally four events of subsidence including two events after upheaval of granite body and two events after sedimentation of unconsolidated sedimentary layer formed the macroscopic tensional lineament. The subsidence was occurred by tensional stress oriented ENE-WSW direction and compressional stress oriented NNW-SSE direction. The deeper distribution of tuff and unconsolidated sedimentary layer as much as 70-140m and that of granite as much as 50-500m at Hamdeok and Shinheung than those of the eastern and the western area around Hamdeok and Shinheong is due to the Hamdeok-Pyoseon Graben by three events of differential subsidence from Hamdeok to Pyoseon including Shinheung.

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.295-304
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• 2011

The first step in improving our understanding of uncertainties suclt as rock mass strength parameters and deformation modulus in rock masses around high-level radioactive waste disposal repositories, for improved safety, is to study the process of crack development in intact rock. Therefore, in this study, the fracture process and crack development were examined in samples of KURT granite taken from the KAERI Underground Research Tunnel (KURT), based on acoustic emission (AE) and moment tensor analysis. The results show that crack initiation, coalescence, and unstable crack occurred at rock uniaxial compressive strengths of 0.45, 0.73, and 0.84, respectively. In addition, moment tensor analysis indicated that during the early stage of loading, tensile cracks were predominant. With increasing applied stress, the number of shear cracks gradually increased. When the applied stress exceeded the stress level required for crack damage, unstable shear cracks which directly result in failure of the rock were generated along the failure plane.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.311-319
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• 2008

Evaluation of an amplitude domain reflectometry (ADR) type soil moisture sensor as ThetaProbe ML2x using the response of frequency impedance was performed in a variety of soil porous media such as Jumunjin standard sand, weathered granite soil at Sangju area, and weathered gneiss soil at Jangsu area. The tested soils were classified with a dried condition and a wetted condition for comparing with soil volumetric water content under different installed depths of the measurement sensor. In the results the part of measurement rod including one signal rod and three shield rod 6cm in length was found to decrease the variation of measurement output voltage with insert 5cm over into the soil porous media. The measurement output voltage was verified to more stable output voltage under weathered granite soils and weathered gneiss soils contained the fine grain materials such as clay and silt minerals than the gradual grain material like as the standard sands. Therefore, measurement values by soil moisture sensor can be offered the more stable values when an contact volume between soil porous media and measurement sensor increase.