• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.291-296
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• 2007

We measured potential waveform of load, displacement, micro electric signal generated by rock and mortar fracture using PXI A/D Converter. The rock type used for measurement was used granite, limestone and sandstone, and mortar specimen. we made measuring equipment of physical properties to confirm basic information of physical properties, measured physical properties of rock engineering, electric resistivity and seismic velocity. Potential waveform system was built using PXI A/D Converter and measured potential waveform of load, displacement, micro-electric signal generated using this during uniaxial compressive test by the specimen finished such test of physical properties. Using the saturated rock and mortar specimen, micro electric signal increased, and It didn't increase a signal in dried rock and mortar specimen according as load and strain rate increases. But signal also increased in saturated or dried specimen in case of sandstone. It was possible to check the close correlation relationship the signal and fracture behavior by a compressive load as the signal of fracture position was increased bigger than the other position. It was also possible to check the correlation relationship between physical properties and micro geo-electric signal.

• Journal of The Geomorphological Association of Korea
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• v.23 no.1
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• pp.1-16
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• 2016

This study estimates relationships between physical and chemical weathering indices of various rock types and topographical relief. Physical weathering properties such as rock strength and joint and chemical weathering indices such as the $SiO_2/Al2O_3$, CIA and WPI were analyzed from 18 rock outcrops in mountain and valley areas consisting of 9 rock types. The results indicate that the elevation and relief of topography increase physical strength of rock increases. It can be suggested that the total r(rock-mass strength rating) and R(rock rebound strength by Schmidt Hammer) are most useful indices as a quantitative weathering property factor to explain formative causes of topographical relief. The results also suggest that rock types such as sandstone, granite, gneiss and schist are most suitable to explain meaningful difference in topographical relief with the physical and chemical weathering indices.

• The Journal of Engineering Geology
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• v.34 no.1
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• pp.25-38
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• 2024

Laboratory tests of accelerated artificial weathering compared the effects of seawater and acidified distilled water on rock weathering. The experiments simulated chemical and physical weathering of five different types of volcanic rock by applying 45 freeze-thaw cycles using seawater and acidified distilled water (pH 3), both at 70℃. The physical properties and uniaxial compressive strength (UCS) of the rocks were measured after 15 and 45 cycles of artificial weathering. Most of degradation of physical properties appeared within the first 15 cycles, and acidified distilled water had a greater effect than seawater. Analysis of variance (ANOVA) statistically evaluated the differences in UCS of the different rock types during the tests. The rate of UCS reduction after 45 cycles was similar across the samples, being independent of the rock type and the trend of changes in physical properties. In contrast to the changes in the physical properties, the UCS was more affected by seawater than by acidified distilled water.

• Geomechanics and Engineering
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• v.11 no.2
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• pp.197-209
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• 2016

Clayey rock has large clay mineral content. When in contact with water, this expands considerably and may present a significant hazard to the stability of the rock in geotechnical engineering applications. This is particularly important in the present work, which focused on mitigating some unwelcomed properties of clayey rock. Changes in its physical properties were simulated by subjecting the rock to a low voltage direct current (DC) using copper, steel and aluminum electrodes. The modified mechanism of the coupled electrical and chemical fields acting on the clayey rock was analyzed. It was concluded that the essence of clayey rock electrochemical modification is the electrokinetic effect of the DC field, together with the coupled hydraulic and electrical potential gradients in fine-grained clayey rock, including ion migration, electrophoresis and electro-osmosis. The aluminum cathodes were corroded and generated gibbsite at the anode; the steel and copper cathodes showed no obvious change. The electrical resistivity and uniaxial compressive strength (UCS) of the modified specimens from the anode, intermediate and cathode zones tended to decrease. Samples taken from these zones showed a positive correlation between electric resistivity and UCS.

• Journal of The Geomorphological Association of Korea
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• v.23 no.3
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• pp.27-39
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• 2016

This study statistically investigates relationships between physical properties of rocks and topography by measuring and analyzing section, topographical and measured parameters of 58 bedrock outcrops at areas covered by gneiss, schist, granite, andesite, sandstone and limestone in the Korean Peninsula. Multiple linear regression analysis suggests that the joint spacing, joint continuity, weathering grade and maximum joint width of rocks among the measured parameters are related to the topographical parameters with statistical significances. Therefore, this study suggests that rock properties such as joint spacing, joint continuity, weathering grade and maximum joint width seem to greatly influence topography, although various factors can affect topographical parameters.

• Tunnel and Underground Space
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• v.6 no.3
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• pp.239-244
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• 1996

Cracks have influence on the physical and mechanical and, more importantly, on the engineering properties of the rock. Physical properties including the volumetric deformation coefficient, electrical resistivity, seismic wave velocity, and the mechanical properties such as the elastic constants and strength of rock are affected significantly by the presence of cracks of various sizes. An experimental program was undertaken to investigate the effect of a finite line crack on the diffraction of the plane compressional wave. Horizontal and vertical components of displacement and acceleration curve were obtained using a single-source and multi-receivers system. A theoretical model from numerical analysis implementing the finite element method was compared with the measured data.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.557-560
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• 2003

Some well-known artificial weathering tests such as freezing-thawing, acid immersion, and salt crystallization are adopted to examine the change of rock properties during the processes of artificial weathering. Granites and other rock types of limestone, marble and basalt collected from different quarries in south Korea were sampled for this study. All tests were performed up to 30 cycles and physical properties were measured after experiencing every ten cycles of artificial weathering tests. During the tests, the variation trends of rock properties were too variable to draw generalized variation patterns but it can be concluded that weathering agents have different effect on rock properties depending on weathering circumstance and time. Even in short terms of salt crystallization tests, some rocks were severely deformed and then burst, and in the early stages of salt weathering, recrystallized salts filling pores and cracks in rocks could be a important factor affecting rock properties.

• Tunnel and Underground Space
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• v.14 no.4
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• pp.261-268
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• 2004

The main objectives of this study are to investigate the anisotropic characteristics of rocks and to evaluate the relationships between physical properties. A series of experiments were performed in three mutually perpendicular directions for three rock types, which are granite, granitic gneiss and limestone. The relationships of measured physical properties were evaluated. The results of ultrasonic wave velocity measurement show that granite of three rock types gives the largest directional difference, and that the wave velocity in a plane parallel to a transversely isotropic one is dominantly faster than that in a subvertical or vertical plane. It implies that ultrasonic wave velocity for rock could be used as a useful tool for estimating the degree of anisotropy. The ratio of uniaxial compressive strength to Brazilian tensile strength ranges approximately from 13 to 16 for granite. from 8 to 9 for granite gneiss, and from 9 to 18 for limestone. The directional differences for granite and granitic gneiss are very small, and on the other hand, is relatively large for limestone. It is suggested that strength of rock makes quite difference depending on the rock types and loading directions, especially for the anisotropic rocks such as transversely isotropic or orthotropic rocks. The ratio of uniaxial compressive strength to point load strength index ranges from 18 to 20 for granite, from 17 to 19 for granitic gneiss, and from 21 to 24 for limestone. These results show that point load strength index makes also a difference depending on rock types and directions. Therefore. it should be noted that the ratio of uniaxial compressive strength to point load strength index could be applied to all rock types. Uniaxial compressive strength shows relatively good relationship with point load strength index, Schmidt hammer rebound value, and tensile strength. In particulat, point load strength index is shown to be the best comparative relationship. It is indicated that point load test is the most useful tool to estimate an uniaxial compressive strength indirectly.

• Economic and Environmental Geology
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• v.32 no.1
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• pp.1-11
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• 1999

In the last decade, the supply of natural aggregates has been continuously increased due to the other types of aggregates. In general, aggregates constitute 70-80% of the total volume of concrete, so the quality of aggregates is main factor controlling physical characteristics of concrete. For this reason, physical properties of aggregate according to different rock types were studied. The majority of crushed aggregates is taken out of granite, gneiss, sandstone, andesite, basalt and so forth. The physical properties of these rock types were tested and most of them fell within the acceptable limit on the base of Korean standard regulation. The major lithology of the crushed aggregates is granite and gneiss, both of which are marked for more than 50% of total lithology thpes in Korea. A to the physical properties of granite, the high specific gravity coincides with low porosity, low absorption ratio, while the abrasion and soundness index show, in general, no specific trend. It has been assumed that slight differences of the physical properties of granite aggregates are related with those of the mineral composition, grain size, and so on. In comparison to granite, the physical properties of gneiss have little correlation one after another. This trend is related to different mineral composition, grain size and typical sheet fractures typically prevailing in the texture of gneiss. Spatial pattern of physical properties shows that high specific gravity of granite coincides only with low porosity and absorption ratio in all provinces except Cheolla province, and high specific gravity of gneiss coincides with low porosity and absorption ratio only in Cheolla and Gandwon provinces.

• Tunnel and Underground Space
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• v.18 no.5
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• pp.317-327
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• 2008

About 70% of domestic land is mountainous and the construction of many geotechnical structures is inevitable for building transportation networks across region. Many geotechnical surveys, including rock physical and mechanical tests, are performed during construction. Thus study is a basic research for establishing database of physical and mechanical properties in domestic rocks, and analyzing the rock mechanical relationships between 2,000 rock properties obtained from laboratory tests in KOLAS. For the construction of useful database, systematic management, based on the standard information as well as reliable data accumulation, is required.