• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.100-105
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• 1995

The aim of this study is to developed water proofing properties of cement mortar this study the effect of mix proportion on the basic characteristics of cement mortar was investigated. Also water absorption and permeability properties of mortar using several admixtures were tested. from this results, Physical properties of mortar is improved by using the sand witch has a broad particle size distribution. Also the sililca alumina powder is effective for decreasing the water permeability of mortar and zinc stearate is in creasing the water repellence property.

• Journal of the Korean Geotechnical Society
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• v.34 no.2
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• pp.19-32
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• 2018

During the process of gas hydrate extraction in the deep seabed, fine diatom particle migration occurs, which causes the seabed slope failure and the productivity deterioration of the gas hydrate. Therefore, a study related with the changes of the ground characteristics due to the fine particle migration is required. The objective of this study is to investigate the change of hydraulic properties of sand due to the migration of fine diatom particle in sandy soils. In order to simulate the sediments of the Ulleung basin gas hydrate in the East Sea, fifteen sand-diatom mixtures that have different diatom volume fractions (DVF) are prepared. During the falling head permeability tests, the coefficients of permeability are measured according to the DVF. In addition, for the simulation of the fine diatom particle migration, constant head permeability tests are conducted by applying the hydraulic pressures of 3 kPa, 6kPa, and 9 kPa on a specimen composed of two layers: a specimen with 50% DVF in upper layer and a specimen with 0% DVF in lower layer. Furthermore, the coefficient of permeability and the electrical resistivity of the migration zone are measured during the constant head permeability test. The falling head permeability tests show that the coefficient of permeability decreases as the DVF of the specimen increases. In addition, the gradient of the coefficient of permeability curve decreases in the DVF range of 10%~50% compared with that of 0%~10%, and increases above 50% in DVF. The result of constant head permeability tests shows that the coefficient of permeability decreases and electrical resistivity increases in the migration zone due to the fine diatom particle migration. This study demonstrates that fine diatom particle migration reduces the permeability of the soils and the behavior of the migration zone due to the fine diatom particle migration may be estimated based on the reversal relationship between the coefficient of permeability and the electrical resistivity.

• Geotechnical Engineering
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• v.13 no.6
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• pp.37-44
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• 1997

In this paper, the effects of crude oil contamination on the geotechnical properties of sand such as compaction characteristics, shear strength, permeability, and bearing capacity are presented. The test results indicate that the compaction characteristics are somewhat influenced by oil contamination. The angle of internal friction of sand based on total stress analysis decreases due to the presence of oil within the pore spaces in Band. The bearing capacity of sand is significantly influenced by oil contamination.

• Journal of Korea Foundry Society
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• v.4 no.1
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• pp.12-20
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• 1984

In order to investigate the effect of size of sand grains, bentonite content and moisture on mixing power, standard mixing power, permeability, green compressive strength and green mold hardness were measured with mixing time, and also coated layer of mixed sand with time was observed by optical microscope and scanning electron microscope. From this experiment, the results were summarized as follows. 1. Mixing power increased as size of sand grains decreased. 2. Mixing power increased gradually as bentonite content increased and in particular, increased rapidly in 7-10% bentonite. 3. Mixing power increased as moisture content decreased. 4. The mixing time required to get the optimum mixing power decreased as moisture content and grain size increased, but increased as bentonite content increased.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.329-336
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• 1998

Sandmats are used to dissipate trapped water rapidly from the embankment built on marine soft ground. At present, however, it becomes difficult to obtain qualified sands since natural resources such as river sand are to exhausted. Also, low permeability of sand may cause low degree of consolidation and instability of embankment. In this study, design and construction methods was discussed. Drainage capacities of prefabricated horizontal drains which were installed in highway construction site are investigated in order to find possible substitution for river sands as drainage materials. On the basis of measurement data at the construction site, it was concluded that use of the prefabricated horizontal drains shows satisfactory drainage capacity without instability of embankment.

• Geomechanics and Engineering
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• v.5 no.6
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• pp.575-594
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• 2013

Organic soils exhibit problematic properties such as high compressibility and low shear strength; these properties may cause differential settlement or failure in structures built on such soils. Organic soil removal or stabilization are the most important methods to overcome geotechnical problems related to peat soils' engineering characteristics. This paper presents soil mechanical intervention for stabilization of peat with sand columns and focuses on a comparison between the mechanical characteristics of undisturbed peat and peat stabilized with 20%, 30% and 40% of sand on the laboratory scale. Cylindrical columns were extruded in different diameters through a nearly undisturbed peat sample in the laboratory and filled with sand. By adding sand columns to peat, higher permeability, higher shear strength and a faster consolidation was achieved. The sample with 70% peat and 30% sand displayed the most reliable compressibility properties. This can be attributed to proper drainage provided by sand columns for peat in this specific percentage. It was observed that the granular texture of sand also increased the friction angle of peat. The addition of 30% sand led to the highest shear strength among all mixtures considered. The peat samples with 40% sand were sampled with two and three sand columns and tested in direct shear and consolidation tests to evaluate the influence of the number and geometry of sand columns. Samples with three sand columns showed higher compressibility and shear strength. Following the results of this laboratory study it appears that the introduction of sand columns could be suitable for geotechnical peat stabilization in the field scale.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.93-105
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• 2001

The permeability of converter slag, replacing material of sand mat on improving soft clay foundation, was evaluated in the laboratory as well as in situ test. Effects of grain size, flow water time and aging were investigated using sea and fresh water Converter slag which has a grain size less than 10mm were submerged with fresh water and sea water. In fresh water, the coefficients of permeability in samples A and B were measured as 4.50${\times}$10$^{-2}$ cm per second and 1.20${\times}$10$^{-1}$ cm per second, respectively while as 1.88$\times$10$^{-2}$ cm per second and 3.86$\times$10$^{-1}$ cm per second in sea water. The condition of turbulent flow may exit and was experimentally certified based on the relationship of hydraulic gradient and seepage velocity. After 180 days in using sea water, the coefficients of permeability of samples A and B decreased ten times smaller than those initial values, and after that time continually decreased as for till 360 days. Finally, filling with voids in high-calcium quicklime(CaO) may result in the reduction of coefficient of permeability. In-situ coefficient of permeability however was Practically satisfactory.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.111-120
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• 2007

This paper is results of experimental research on the effect of application of similarity related to permeability of soil on the consolidation behavior as centrifuge modeling of consolidation is performed with the centrifuge model facility. In this research, the permeability of soil was controlled by changing the viscosity of porewater as the mixed water with glycerin was used during the centrifuge model experiments. The effect of drainage path on consolidation was investigated by installing the vertical drains. A serise of centrifuge model tests with conditions of single vertical and radial horizontal drainage were carried out. Kaolinite and Jumunjin standard sand were used as soft clay and surcharges respectively during tests. For testing condition of single vertical drainage considering similarity of permeability, it was found that consolidation with mixed porewater with glycerin was delayed in comparisons sons with test results with water only. For conditions of horizontal drainage with vertical drains, a low permeability by changing the viscosity of pore water resulted in delayed degree of consolidation at an initial stage of consolidation. But, it predicted not much differences in settlement as long as the consolidation time was sufficiently long enough to finish consolidation. Consequently, it was found that similarity in permeability should be considered to be critical for the case of centrifuge model experiments related to consolidation with long drainage path.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.11-24
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• 2003

This paper presents the results of laboratory investigation performed to study the role of different air sparging system parameters on the removal of benzene from saturated soils and groundwater. A series of one-dimensional experiments was conducted with predetermined contaminant concentrations and predetermined injected airflow rates and pressures to investigate the effect of soil type and the use of pulsed air injection on air sparging removal efficiency. On the basis of these studies, two-dimensional air sparging remediation systems were investigated to determine the effect of soil heterogeneity on the removal of benzene from three different homogeneous and heterogeneous soil profiles. This study demonstrated that the grain size of the soils affects the air sparging removal efficiency. Additionally, it was observed that pulsed air injection did not offer any appreciable enhancement to contaminant removal for the coarse sand; however, substantial reduction in system operating time was observed for fine sand. The 2-D experiments showed that air injected in coarse sand profiles traveled in channels within a parabolic zone. In well-graded sand the zone of influence was found to be wider due to high permeability and increased tortuosity of this soil type. The influence zone of heterogeneous soil (well-graded sand between coarse sand) showed the hybrid airflow patterns of the individual soil test. Overall, the mechanism of contaminant removal using air sparging from different soil conditions have been determined and discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.2
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• pp.107-116
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• 2002

The amount used of aggregates for concrete is increasing rapidly since the mid-1980s in Korea. The natural gravels from river are already displaced with crushed stone, and use of crushed sand as a substitute of natural river sands, also, is getting increased day by day. This paper is presented fur analysis on mechanical properties of high strength concrete using fly ash and crushed sand. The material functions in mixing design of concretes are various water-cement ratios(w/c) such as 0.25, 0.40, 0.55 and different replacement ratio of crushed sand to natural sands such as 0%, 20%, 40%, 60%. As a results, it has been shown that compressive strengths of concretes with W/C lower than 0.40 and 0.25 are higher than 400 kgf/$\textrm{cm}^2$ and 600 kgf/$\textrm{cm}^2$ respectively. It is also concluded that the results of rapid chloride permeability tests of concrete are evaluated to negligible. The conclusions of this study is that it is possible to use fly ash and crushed sand fur high strength concrete.