• Tunnel and Underground Space
• /
• v.6 no.2
• /
• pp.175-183
• /
• 1996

Linear cutting tests on granite were conducted to evaluated the cutting performance of abrasive water jet(AWJ) using several types of abrasives. The abrasives used in the tests were grarnet, alumimum oxide, and silicon carbide. And one type of granite which is comercially known as "KeuchangSuk" was used as workpiece throughout the tests. The results from the tests were described in terms of cutting depth and abrasive productivity. Authors tried to confirm the effects of the operational parameters of abrasive mass flow rate, water pressure, and traverse speed of nozzle on cutting depth and presented almost all the data obtained in the tests. Abrasive productivity can be defined as the area of kerf wall cut by unit weight of abrasive and is an important factor to evaluated the cutting ability of abrasive and assess the cost effectiveness of an AWJ system. In the tests the maximum abrasive productivities of garnet, alumina, and silicon carbide were about 0.21, 0.24, and 0.20 $\textrm{cm}^2$ respectively under similar operational conditions.onditions.

• Economic and Environmental Geology
• /
• v.33 no.2
• /
• pp.139-146
• /
• 2000

Development of an effective liner by utilization of the tailings frm the Imcheon mine and polymer has been tried. The tailings piled in the Imcheon mine, whose true specific gravity is about 2.86, are composed mainly of quartz, alkali-feldspar, muscovite and pyrite, and mostly (93.7% in volume) coarser than sand grain size (50${\mu}{\textrm}{m}$). Strength, leaching and permeability tests have been performed on the test specimens of polymer concrete manufactured with various mixing proportions of tailings, unsaturated polyester resins(UPR), calcium carbonates, stone powder sludges and granite soils. Polymer concrete specimens with stone powder sludges or granite soils as fillers and aggregates indicate 2.5 to 3 fold higher flexural and compressive strengths and lower permeabilities than those with calcium carbonates, which shows their usability as a waterproof liner. Also, the polymer concrete liner with stone powder sludge fillers is more advisable in aspects of utilization of waste sludges than that with other fillers.

• Economic and Environmental Geology
• /
• v.27 no.3
• /
• pp.231-236
• /
• 1994

Fluid inclusions have been studied in phenocryst quartz from the Cretaceous porphyritic granite. Three main types of fluid inclusion were found: liquid-rich inclusion (I type), gas-rich inclusion (II type) and solid-bearing inclusions (III-A, III-B). The solid-bearing inclusions (III-A, B) represent the earliest trapped fluids. They have salinities between 63 and 67.5 wt.% equivalent NaCl. These are high saline inclusions containing NaCl and KCl daughter crystals. Homogenization temperature inferred from the fluid inclusion study ranges from 620 to $700^{\circ}C$. Type I and II inclusions were observed within the same fracture. This cause for these differences in degree of filling is evidence of boiling. Salinities of type I and II inclusions range from 10.24 wt.% to 13.44 wt.%, from 8.4 wt.% to 11.48 wt.% NaCl equivalent, respectively.

• Geotechnical Engineering
• /
• v.12 no.4
• /
• pp.87-100
• /
• 1996

The pull -out test has been used to investigate the friction properties between soil and grid type geosynthetics which is useful to measure the passive bearing resistance as well as the skin friction. In this paper, the friction properties between geogrid and a weathered granite soil are investigated by performing various pull-out tests. From the test results, a rational pull out test equipment and test method is suggested by evaluating the effects of major factors (such as geogrid width, location of soil box facing, vertical loads and pulll -out displacement rate, etc.) on pull -out test results.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2003.11a
• /
• pp.206-213
• /
• 2003

Laboratory testing of representative rock specimens is of fundamental necessity for the successful design and/or assessment of facilities associated with many kinds of underground exploitation, including the geological disposal of radioactive nuclear waste. As a fundamental and systematic study, a series of measurements of the physical, mechanical and hydraulic properties of Inada granite and Shirahama sandstone, two rock types that are widely available in Japan, have been performed. This paper presents the results of a study of the effective porosity, density, compressive and shear wave velocity, unconfined compressive strength and permeability of the two rocks. The anisotropy and the effects of confining pressure on the permeability of the rocks, as well as the relationships among the physical, mechanical and hydraulic properties, are also investigated and discussed.

• Economic and Environmental Geology
• /
• v.32 no.5
• /
• pp.519-535
• /
• 1999

Precambrian metasedimetay rocks in the Sunchang Shear Zone (so-called Seologri and Yongamsan Formation) consist of black slate, phylite, mica schistm quartzite and rarely calc schist. The metamorphic rocks in the area have undergone at least three stages of metamorphism, which are two prograde (M1 and M2) and one contact metamorphism (M3). The metamorphism which made the most prevailing mineral assemblages in the area, is M2 stage metamorphism. The metamorphic grade of M2 methamorphism in metapelites increases from the Chlorite zone through Biotituzone, Garnet zone to Staurolite zone. The M1 stage metamorphism is recognized by kyanite and sillimanite pressure type regional metamorphism. The M3 stage methamorphism is represented in the contact boundary, which area is the chlorite zone and biotite zone near the Sunchang foliated granite and the namwon granite. The M3 stage methamorphism is characterized by andalusite bearing mineral assemblages. The peak temperature condition of M2 metamorphism estimated from coexising garnet and biotite (Kretz, 1990) is 518~598$^{\circ}C$.

• Economic and Environmental Geology
• /
• v.1 no.1
• /
• pp.70-73
• /
• 1968

In Korea, ground water exploration by the electric method as a major prospecting tool has been carried out mainly in alluvial deposits, So it is considered to be important to understand the principle concerning the electrical and hydrological properties of alluvium. Factors which affect on the electrical and hydrological properties of alluvium were investigated. Major elements in ground water exploration are porosity and dermeability for most alluvial deposits with exceptions in some particular areas. Much water yield can be expected where alluvial materials have large porosity and small particle size while large particle size in necessary for good permeability. Problem is to locate the points which have comparatively large porosity and good permeability at a time. It is known that electrical resistivity method is proved useful to solve the above problem. The conclusion is: Localities which have greater alluvium thickness(7 to 10m) and 200 to 500 ohm -m of real resistivity value are suitable for well site in alluvial deposits in Korea where alluvium thickness is comparatively small(less than 10m in generaa) and bedrock formations are mainly composed of granite gneiss and granite.

• Tunnel and Underground Space
• /
• v.18 no.3
• /
• pp.214-218
• /
• 2008

Dynamic fracturing of anisotropic granite was investigated by SHPB (Split Hopkinson Pressure Bar). Energy absorption during the test and maximum stress were increased as strain rate increased. Maximum stresses in every direction were dependent on the strain rate but not so sensitive to anisotropy. Elastic wave velocity was decreased as strain rate increased and dependent on strain rate in every direction. Especially, elastic wave velocity decreased more rapidly in a strong rock.

• Economic and Environmental Geology
• /
• v.30 no.3
• /
• pp.231-240
• /
• 1997

The behavior of rocks and microcrack development due to fatigue stresses are investigated using cyclic loading tests and ultrasonic velocity measurements. Twenty six medium-grained granite samples from the Pochon area are selected for measurements. Ultrasonic velocities are measured for samples before fatigue test to characterize the pre-existing microcracks. Then, thirteen different cycles of loadings with 70% and 80% dynamic strength are applied to the samples. The ultrasonic velocities are measured again to compare velocities after applications of fatigue stress with those before applications of fatigue stress. The results show that most microcracks are developed along the direction parallel to the axis of loading and that the amount of microcracks increases, as loading levels and numbers of cycle increase.

• Economic and Environmental Geology
• /
• v.33 no.4
• /
• pp.309-320
• /
• 2000

Aperture is an important parameter for determining the hydraulic characteristics of fractured media. In this study the topography of artificial rock joint surface was measured using 3D laser profilometer to analyze the aperture distribution. The initial aperture distribution was determined when the contact area became one percent of total joint surface. The initial aperture distribution of granite joint, with the mean value of 0.78 mm and the standard deviation of 0.34 mm was much different from that of the marble joint, with the mean value of 0.57 mm and the standard deviation of 0.26 mm. Apertures of both granite and marble showed normal distributions. Aperture distribution with the contact area of 25% was also analyzed. Mean value was decreased to one third compared to the initial aperture, but the standard deviation was decreased slightly. To determine the spatial correlation of the aperture distribution variogram analysis was carried out on the initial aperture data. Most experimental variograms were fitted well with exponential model. It is expected that the measured aperture characteristics can be used for stochastic analysis of fluid flow through rock joints.