• Journal of Industrial Technology
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• v.34
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• pp.45-52
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• 2014

In this paper the settlement characteristic of shallow foundation on sandy soil overlained by rigid ground was investigated by analyzing results of model tests. For model experiments, model tests were performed with sandy soils sampled from the field, changing the relative density of sandy soil and the ratio of thickness of sandy layer(H) to the width of model strip footing(B). As result of tests, settlement of sandy soils increases as the value of H/B increases, whereas it increases with relative density of soil. Bearing capacity decreases as the thickness of the sand layer relative to the footing width increases. In order to analyze the settlement characteristics of sandy ground, the results of model tests were compared with the predicted values using the empirical formulas proposed by Terzaghi, De Beer and Schmertmann. The method by De Beer was found to be in good agreements with test results.

• 기술발표회
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• s.2006
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• pp.185-192
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• 2006

In this study the case of ground improvement by CGS as injection method were analyzed in order to find out effect of behavior of sandy soil and the application of this method as ground improvement. The study were analyzed N value after CGS work of sandy soil by many sites test. Considering that increase of N value, CGS can be considered as an effective method to increase the bear capacity as well as constrain the settlement of soft ground From the results of this study, N value after CGS work of sandy soil were closed to N value of ground and relative density(Dr), improvement ratio(As) of grouting and the study will be done continuously for finding out relation of them

• Land and Housing Review
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• v.2 no.1
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• pp.79-85
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• 2011

The bearing capacity of a soil can be improved by conventional ground improvement techniques such as stabilization and compaction methods. Recently, the use of geotextiles in improving the bearing capacity of soils has become popular because of the availability of durable and strong geosynthetic materials. In this paper, through the laboratory model tests on sandy ground reinforced by geotextiles with the strip footing under plane strain condition, the effects of bearing capacity improvement on the sandy ground and its behaviour were investigated.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.3
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• pp.18-24
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• 1999

This study was aimed to develope appropriate soil media for the growth of Rhododendron hybrid $J_{ASANHONG}$ on the artificial ground five types of soil media was tested such as "sandy loam-general soil (T1)", "vermiculite-artificial soil (T5)", "sandy loam 50% + vermiculite 30% + sand 20% (improved of soil 2-T2)", "sandy loam 50% + carbonized rice hust 30% + sand 20% (improved of soil 3-T3)", "sandy loam 50% + humus sawdust 30% + sand 20% (improved of soil 4-T4)". The result of the research are as follows. 1. Among the type of soil media, the sandy loam(T1) soil type gave the worst effects on growth of above ground parts(height, No. of leaf, width of leaf, No. of flowering, dry weight of upper parts) and under ground parts(dry weight of roots). 2. Vermiculite(T5) showed the highest root growth(dry weight of roots). it seemed to be caused high saturated hydraulic conductivity and porosity. As a result, there is much available space for enabling the root spreads. 3. "sandy loam 50% + vermiculite 30% + sand 20%(improved of soil 2-T2)", "sandy loam 50% + carbonized rice hust 30% + sand 20%(improved of soil 3-T3)" showed good effects on growth of above ground parts and under ground parts compared with sandy 10am(T1) 4. "sandy loam 50% + humus sawdust 30% + sand 20% + (improved of soil 4-T4)" showed the highest effects on growth of above ground parts.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.201-217
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• 1999

Bearing capacity of soil can be improved by several conventional ground improvement techniques like stabilization and compaction. In recent time, the use of reinforced soil has become popular due to the availability of durable strong geosynthetic materials. In this papers, through the laboratory model tests on sandy ground reinforced by mats about the strip footing under plane strain condition, the effects of bearing capacity improvement and behaviour of sandy ground were observed. And bearing capacities calculated by proposed method and measured by tests were compared.

• Journal of the Korean GEO-environmental Society
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• v.7 no.5
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• pp.67-77
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• 2006

Bearing capacity of soil can be improved by several conventional ground improvement techniques like stabilization and compaction. Recently, the necessity on the reseaches for the bearing capacity of footing reinforced by Geotextile is being significantly increased. In this paper, a series of model tests on sandy ground reinforced by a layer of Geotextile were performed under plane strain condition, and the effects of bearing capacity improvement and behaviour of sandy ground were observed through tests for position and horizontal length, material strength of reinforcement.

• Asian Journal of Turfgrass Science
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• v.5 no.2
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• pp.87-94
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• 1991

This study was carried out to determine the optimal seeding rate of Korean lawngrass in three different soil textures. The results obtained are summarized as follows;1.In early development, there were not significant differences in leaf length and width except for leaf width in mean seeding rates. And there was significant difference in tillering number. Tillering number of Korean lawngrass grown in sandy clay loam soil was more abudant than that grown in sandy clay and sandy loam soils.2.The rate of ground cover of Korean lawngrass grown in sandy clay loam soil was faster than that in other soils. The ground cover rate was faster in the following order: 15, 12, 10, 7, 5, 3 kg/10a. But in sandy clay loam soil, it was showed that the plot seeded at 12kg/10a be faster than that at l5kg/10a. Plots seeded from 5 to 15kg/10a in sandy clay loam soil and 15kg/10a in sandy clay soil were showed the 100% ground cover during the period of the year seeded.3.There were not significant differences in dry weight of each part measured at 11 and l4months after seeding. But there were significant differences in dry weight of shoot and total dry weight. Total and shoot dry weight of Korean lawngrass grown in sandy clay loam soil were heavier than that in others. 4.It was revealed that the optimal seeding rate in sandy clay loam soil was 12 kg/10a. But it was suggested that the optimal seeding time and rate in each soil textures be undertaken in future.

• Journal of Soil and Groundwater Environment
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• v.14 no.3
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• pp.47-56
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• 2009

This is a study about how the increase of strength is changed when ground improvement material is mixed with either coastal clay or sandy soil. The ground improvement material was made from mixing a certain proportion of the slag which is by-products generated by smelting the iron ore and the paper fly ash which is formed by bumping up the paper. The ground improvement material was added to coastal soil and sandy soil each. And then according to ratio of water contents, number of curing days and ratio of mixture, specimen for uniaxial compression test was made. The change of uniaxial compression strength and the generated substances was analyzed while the specimen is being cured for 28days. The result of analysis shows that the strength of coastal clay was increased about eleven times more than that of sandy soil. This means that ettringite reaction by ground improvement material becomes more distinctive in the coastal clay than in the sandy soil.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.1
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• pp.1-9
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• 1999

To find pertinent soil type and maintenance method for artificial planting ground, the effects of soil compositions{sandy loam(S), vermiculite(V), sandy loam+vermiculite+sand(SVS), sandy loam+ carbonized rice husk+sand(SCS), sandy loam+humus sawdust+sand(SHS)}, and fertilizers (organic, chemical) on plant(kentuckyblue grass) growth were measured and compared from the field experiment. The results are summarized as follows 1. the highest germination rate is found from "vermiculite(V)" and the lowest from "sandy loam(S)" among tested 5 soil compositions. 2. "sandy loam+vermiculite+sand(SVS)" composition shows the highest plant height growth effect (5cm growth during tested 3 months) comparing to other 4 compositions. 3. "sandy loam+vermiculite+sand(SYS)" composition shows the highest ground covering rate after first two months, but it concede its order to "sandy loam+humus sawdust+sand(SHS)" composition after next one month growing. 4. the effects of fertilizers are follows 1) Among the blocks where no fertilizer was tried, the predominant height growth was obvious in "sandy loam+carbonized rice husk+sand(SCS)" and "sandy loam+humus sawdust+sand(SHS)" composition. 2) Among the blocks where chemical fertilizer was tried, relatively positive results were found from "vermiculite(V)" and "sandy loam+vermiculite+sand(SYS)" blocks on germination and growth rate. But on the ground coverage ratio, the effect of "sandy loam+carbonized rice husk+sand(SCS)" composite precede that of those 2 composites. 3) Among the blocks where organic fertilizer was tried, "sandy loam+humus sawdust+sand(SHS)" and "vermiculite(V)" blocks show relatively high ground coverage rate, growth rate than others. 4) When compositional differences were not considered, the block where organic fertilizer was tried shows most positive effects on all 3 measurements-germination ratio, height growth and ground covering.

• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.7-13
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• 2008

The tillage depth control system is one of the most salient control system of tractor implements. A contact-type height sensor was developed to measure ground clearance for the tillage depth control. The height sensor was fabricated in this study, and its efficacy in a tillage depth control system was evaluated. Experiments were conducted in order to determine both static and dynamic detection characteristics of the height sensor using soil bin system on the sampled soil (sandy loam, sand, clay loam). The results of the static detection characteristics showed that in the case, sandy loam soil despite and clay loam soil at a wet basis moisture content of 30%, large measurement errors were observed a due to penetration of a plastic puck into the sampled soil. The results of the dynamic detection characteristics showed that the height sensor detected the distance from the ground of sandy loam soil despite the uneven nature of the ground surface and the changes in traveling speed $1km/h{\sim}5km/h$ at a wet basis moisture content of 10%.