• Explosives and Blasting
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• v.22 no.2
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• pp.33-43
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• 2004

The six grades weathering system is normally used in weathered rock classification. In this study. fresh and weathered rock block of grade I to V were sampled in Jang-soo ana but samples of the grade VI was omitted from this study. The variation quantities of chemical weathering indices with weathering degree are smaller than those of physical and mechanical properties. Increase of Weathering degree is well indicated by physical and mechanical properties such as strength, hardness, ultrasonic velocity and slake durability result. Especially, absorption and porosity ratio is a good indicator. As weathering proceeds. a number of the cracks affect the rock deformation. Therefore, stress-strain curves of weathered rocks in unconfined state are quite different from ones of fresh rocks.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.23-35
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• 2004

The weathering characteristics of periodically submerged sedimentary rocks in the Sayeon dam, Ulsan was examined by field work, electron probe micro-analysis, X-ray diffraction, and X-ray fluorescence spectrometry. Analysis of fracture zone and exfoliation showed the submerged sedimentary rocks have undergone severe mechanical weathering. Mechanical weathering in the water-rock interface accelerated chemical weathering, such as dissolution and alteration of the most of minerals except for quartz in the weathering zone. The dissolution of carbonates specially calcite, is remarkable creating the cavities, whereas formation of minerals including clay minerals is not active. The sedimentary rocks have been periodically submerged for a certain period of time, and have repeated freezing and thawing. This mechanical weathering favored infiltration, which accelerated mineral dissolution. The high content of easily soluble carbonate of the sedimentary rocks is likely the major cause of intense chemical weathering. The dissolved elements within the infiltrated water interrupted the occurrence of clay and weathering minerals, and expend fractures by infiltrated water accelerated weathering process.

• Journal of the Korean Geographical Society
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• v.28 no.2
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• pp.99-111
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• 1993

The transformation of rocks into unconsoli-dated debris is the prime geomorphic processes including weathering and soil forming process. In these processes, rocks tend to be unconsol-idated debris with small particles. Particularly, typical granite is more likely affected by weathering, since the rock consists of quartz, feldspar and mica that can be easily coarse-grained and well jointed without bedding. The purposes of this study are to clarify the index and properties of mechanical weathering that contributed to transformation of granite distributed in Korea. A total of seventy-three samples of weathering products of granite in Korea were collected during the three-year period, March 30, 1989 to February 21, 1992. The prticle analysis was performed for clay, silt and sand using Sieve and Hydrometer. The results of the analysis are as the followings: First, soil textures in the study area are included seven categories of textures as C, CL, SCL, Sil, SL, LS, and S. Among these textures, the most frequent soil texture were SL, S and SCL in order. Second, the weathering products of granite are crumbled by weathering and hydrothermal. Clay texture consisted of fine materials seems to be influenced by hydrothermal, while Sand texture composed of coarse materials, seems to be significantly influenced by weathering. Third, the index of mechanical weathering by region indicates that Hawngdeung(1) is the lowest as 2.37 and the index by soil texture shows that Clay texture is the lowest as 2.46. Forth, the regression analysis of MW showes that sand/clay variable is the most significant variable. Finally, pedochemical weathering is prevailed on the clayey gruss and geochemical weathering is on the gruss and shattering is on the weathered rock, strongly, but the fine materials in some sites were formed by argillation of hydrothermal.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.37-47
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• 2005

The purpose of this study is to estimate the bearing capacity and settlement characteristics of the weathered granite masses, and on the process to achieve the purpose, in the first place, the weathered degree according to the absorption index was examined and reviewed, then plate bearings test in in-situ depth were tested, and finally the result was compared and examined with the result of the existing, estimate method and pressuremeter test. In order to achieve the purpose of this study, a typical area distributed with weathered granite masses, gyeonggi area, was chosen as a sample site for testing, and in the result, it appeared and found out that the more the weathered degree increases when the plate bearing test are tested, the more the bearing capacity decreases a numerical indexes and the more greatly the width of the decrease of bearing capacity increases around the boundary of specific, weathered degrees. Also, In the result from estimating the bearing capacity of weathered granite masses by the existing, suggested formula, it appeared that there is a tendency that the more the weathered degree increases, the more similar the bearing capacity becomes with the result of plate bearing tests.

• Tunnel and Underground Space
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• v.21 no.2
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• pp.145-150
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• 2011

Variations of physical properties such as weight loss rate, wave velocity and uniaxial compressive strength after performing freeze-thaw cyclic test were measured in order to define weathering characteristics of sandstone and andesite. Weight change in specimens of the two rocks decreased with increasing the repetition number of freeze-thaw cyclic test. In particular, weight loss of andesite specimens was very irregular. P-wave velocity of sandstone specimens decreased more than 5%. On the other hand, P-wave velocity of andesite specimens do not vary up to 500 cycles and decreased more than 5% after 1000 cycles. This implies that the sandstone are easily weakened and loosened by weathering processes, while the andesite are relatively strong. In addition, the wave velocity changes of the andesite specimens coincident with the weight change. Uniaxial compressive strengths of the sandstone specimens slightly decreased at the early stage of the freezing-thawing cyclic test, then tended to be irregular after 64 cycles. In conclusion, the rock specimens showed smaller weight loss, less had lower strength reduction rate.

• The Journal of Engineering Geology
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• v.2 no.1
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• pp.36-46
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• 1992

Granite core samples and bulk samples were first subjected to petrographic examination to determine weathering degrees. Secondly, their physical or mechanical properties including specific gravity, porosity, sonic wave velocity and uniaxial compressive strength were measured. The results were correlated to investigate the influences between properties including physical and mechanical properties, weathering degrees, and rock textures. Porosity and P wave velocity were found the most useful indices in determining the weathering degrees of granites.

• Geotechnical Engineering
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• v.13 no.6
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• pp.13-24
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• 1997

In Korea, granite is abundant and occupies around two-thirds of the country's ground. Bven though weathered granite residual soils are widely distributed, undisturbed sampling of this soil is extremely difficult because of the particultate structure. This difficulty has kept away the researchers from investigating !he deformational characteristics of weathered granite residual soil. Thus, a special undisturbed sampling device was developed and undisturbed samples were prepared for triaxial compression (TX), resonant column(RC), and torsional shear (75) tests. Local deformation transducer (LDT) was fabricated for internal strain measurements during TX tests. Both undisturbed samples and statically compacted samples of same density were tested by using TX with LDT, RC, and 75 test equipments. The behaviour of statically compacted specimens was almost the same as that of undisturbed samples in the strain ranges below 1 percent. The stiffness and strength decreased with increasing degree of weathering. In case of undisturbed specimens, strains at failure are widely varied from 2 percent to 11 percent, and planes of failure are irrelevant to the angle of internal friction due to the inhomogeneous nature.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.612-614
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• 2007

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2005.03a
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• pp.97-110
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• 2005

• Journal of the Korean Geographical Society
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• v.41
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• pp.1-18
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• 1990