• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.37-40
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• 2008

We have measured resistivities for undisturbed soil samples collected from dredged bank with sea sand, and analyzed with one-dimensional inversion results from small-loop electromagnetic survey data. From the relationship between the two resistivities, it appeared that calculated resistivities were remarkably consistent with measured resistivities. Correlation relationships between resistivity values and cone resistance were analyzed after comparing inversion results with cone resistance. It turns out that the region with below 1 ohm-m is correspondent to that of with less than $50\;kgf/cm^2$ in dredged bank with sea sand. From the study result, resistivity monitoring of small-loop EM periodically is proved to be more effective to maintain the stability of embankment dike.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1840-1847
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• 2008

PLT where from site is used mainly with compaction maintenance of quality, CPLT and LFWD, in order to be a Young's modulus of using a direct arrival wave executed a site experiment. According to the roller compaction number of times measured the degree which changes and a promise management aptitude evaluation executed.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.27-35
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• 2002

To construct pipe lines, culverts, or other utility lines, temporary slopes formed by excavating the compacted embankment are frequently met with in the field. Ignoring stability analyses for such slopes and applying inappropriate slope inclinations often result in safety problems. In this study, stability of such slopes were investigated considering the influence of anisotropic shear strength of the layered compacted ground. A series of stability analyses were conducted for slopes varying the slope angle and the height, and assuming isotropic and anisotropic shear strength conditions, respectively. The anisotropic shear strength of the compacted soil was determined from the direct shear test for layered soil blocks varying the inclination angle between the horizontal shear surface and the direction of the soil layer. As a result of the analyses, it has been concluded that the appropriate slope inclination f3r a temporary slope could vary in accordance with the consideration of anisotropy. However, the factor of safety as well as the location of the failure surface did not show significant variation.

• Journal of the Korean Geotechnical Society
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• v.37 no.9
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• pp.25-36
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• 2021

Recently, the intelligent compaction technology for quality control of earthworks has brought attention as a quality control standard for earthworks. In this study, intelligent compaction technology and earthwork quality control methods were investigated and earthwork quality control procedures using intelligent compaction technology were considered based on field tests. Through the field compaction test of the silty sand (SM) fill material, it was confirmed that CMV and bearing capcaity index from plate load tests increased as the number of compactions increased. Based on the field test data, the average CMV and quality control target CMV were derived. The target CMV (34.2) was calculated through the correlation with the bearing capacity index of the plate load test, and the target CMV (36.6) was calculated through the analysis of the CMV increase rate. In this paper, the on-site compaction quality management procedure and methodology using intelligent compaction technology were discussed, and an intelligent compaction quality management method was proposed to promote the applicability of the technology.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.19-25
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• 2009

The current study developed light-weighted mixed soil that can solve problems related with soft soil such as ground subsidence, sliding and lateral displacement of ground. By reducing weight of reclaimed soil through mixing phosphogypsum and recycled EPS beads with the weathered granite soil. A series of geotechnical laboratory tests including physical index test, compaction test, CBR test, and direct shear test were performed and engineering properties were reviewed in order to assess applicability of the light-weighted mixed soil for roads and abutment and various back-filling materials at the reclamation area. Based on the laboratory test results, it was found that the maximum dry unit weight of the light-weighted soil ranges $14.32{\sim}15.79kN/m^3$ and the optimum water content ranges 21.91~24.23%, which means there is 11~19.3% weight decrease effect when comparing with general weathered granite soil. Also it was found that the corrected CBR value ranges 10.4~18.4% satisfying the domestic regulations on road subgrade and back-filling material. In addition, as for shear strength parameter, cohesion ranges 10.79~18.64 kPa and internal frictional angle ranges $35.4{\sim}37.2^{\circ}$, which are similar with those of general construction soil and back-filling material used in Korea. So it can be concluded that light-weighted mixed soil with phosphogypsum can be used effectively for soft reclamation ground as actual filling material and back-filling material. From the current study, it was found that light-weighted mixed soil with phosphogypsum has not only weight reduction effect, but also has no special problems in shear strength and bearing capacity. Therefore, it is expected that phosphogypsum can be recycled in bulk as road subgrade and back-filling material at the reclamation area.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.225-238
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• 2018

In this paper, to investigate the influence of installation damage, a variety of full-scale field installation tests with 15 geosynthetics reinforcements and fill materials of various grain size distribution have been performed. The full-scale field installation test was conducted with reference to the FHWA (2009) guidelines. The tensile strength tests were performed by sampling up to 20 specimens randomly from the excavated geosynthetics reinforcements after compaction of fill material, and the degree of decrease in tensile strength of reinforcements due to compaction was analyzed based on the experiment results. It was found that the degree of tensile strength reduction of geosynthetics reinforcements due to the compaction of fill material is greatly influenced by the type of reinforcement and the maximum diameter of fill material. In addition, it was found that the strength reduction ratio of PET geogrid (PVC coating) with relatively small stiffness was greatest, and that the larger the maximum grain size of the fill material, the greater the strength reduction ratio. And also, a more reasonable evaluation method for the installation damage reduction factor of geosynthetics reinforcements is proposed based on the results of full-scale field installation tests in present study and the existing test results.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.5-16
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• 2012

In the case of using the soil materials created by cutting in-situ ground directly without adjusting particle size, it is recommendable to seek the compaction property or material constant required for filling design or density control through indoor test, and many studies on this subject have been carried out during that time. The researches conducted during that time, however, were focused on the mixed materials with different diameters that exist in a natural condition. There has been no study conducted using coal fly ash that is by-product of the thermal power plant that is actively considered as the building materials. Therefore, this study was aimed at implementing compaction test and examining the basic engineering property in order to explore the influence of crushing the particles through compacting the admixture of crushed stone and coal fly ash produced from thermal power plant on its engineering property, and then the impact of the admixture volume of each material on compaction property and material property by conducting the One-Dimensional Compression Test. As result of compaction test, the optimum moisture ratio of coal fly ash was shown to be approx. 23%. As result of compaction test in accordance with the mixed ratio of coal fly ash and crushed stone under the same compaction energy and moisture ratio, dry unit weight tended to drop when the mixed ratio of coal fly ash exceeded 30%, while it reached approx. $1.81gf/cm^3$ when the mixed ratio was 30%. As result of One-Dimensional Compression Test in accordance with the mixed ratio of crushed stone and coal fly ash, the change in void ratio by particle crushing was at the highest level in the case of coal fly ash 100%, while the lowest level in the case of crushed stone 100%. In the case of mixed materials of crushed stone and coal fly ash, compression index was at the lowest level in case of coal fly ash 30%, and therefore this ratio of mixed material was judged to be the most stable from an engineering aspect.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.203-216
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• 1994

The laboratory methods for compaction of soil (KSF 2312) and for moisture of soil (KSF 2306) in combination with the soil density in place by the sand-cone method (KSF 2311) are generally used for compaction control of soils. However, these methods have limitations in number of test and in accuracy. ]n addition, they are time-consuming. Therefore, they are not adequate for speedy control of embankment compaction in a project with huge amount of earthwork. The RI (Radioisotope) gauges for measurement of soil density and/or of soil moisture are widely used for the compaction control of soils in many countries. But in Korea, they have had a limited usage and available informations for uses of RI gauges are insufficient. Therefore, this study promotes efficient and safe use of RI gauges in geotechnical engineering. In this paper, fundamental aspects such as the priciples of RI gauges, gauge inspection techniques and the applicability and limitations of RI gauges for field usage were reviewed. And a new calibration curves suitable for the Korean soils were suggested.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.89-98
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• 2010

Recently, many researches on bottom ash which is produced in the burning process of power plant are actively performed for its utilization for soil-subbase materials. In this paper, bottom ashes from 5 different power plants are prepared and several tests including compaction, CBR, and tri-axial compression are carried out for mixed bottom ash and weathered soil considering 3 replacement ratio of 30%, 50%, and 70%. Through the tests, CBR result over 20 are evaluated without plastic property, which shows availability of subbase material. With higher increase in replacement ratio of bottom ash, CBR of mixed soil increases due to the higher mechanical performance of bottom ash. However, replacement effects of bottom ash on friction angle and cohesion are evaluated to be little since bottom ash plays a little role in rearrangement of mixed soil. Bottom ash with a good mechanical property is evaluated to have reasonable bearing capacity which shows a good property for subbase materials.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.61-74
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• 2011

This is a fundamental research on use as fill material of lightweight waste such as bottom ash and tire shred. We carried out the test for particle size distribution, specific gravity, density, shear strength, permeability and vertical compression settlement, considering water content change and temperature effect of several waste materials. Bottom ash, which is lighter than soils, has similar permeability and particle size distribution to those of weathered soils. But permeability may differ depending on the particle size distribution. The shear strength aspect of bottom ash and tire shred mixed materials are similar to that of natural fill materials. In the 1-D vertical compression settlement test, we could be assured that bottom ash and tire shred mixed materials showed similar compression settlement to that of sand under actual vertical stress. Furthermore, materials including bottom ash showed smaller compression settlement than that of weathered soils in the long-term settlement test under wetting and freezing-thawing condition.