• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.404-409
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• 2012

In order to obtain optimum mixing conditions with animal cadaver residue and sawdust for composting using rendering treatment method for agricultural recycling, changes of chemical characteristics and compost quality after composting were investigated. Initial mixing ratios with animal cadaver residue and sawdust were adjusted 100 : 0, 50 : 50 and 30 : 70. Temperature, pH, contents of ammonia and carbon dioxide were rapidly increased in 3 days and then decreased with time. Organic matter content was similar in all conditions. In mixing ratio of 50 : 50, the compost quality was satisfied with compost depending on official standard for product fertilizer. Thus, the optimum mixing ratio of animal cadaver residue and sawdust were 50 : 50.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.1-10
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• 2018

Although the soil nailing method is generally used as a gravity grouting, the development and application of pressurized grouting method has recently increased to address the problem of joint generation and filling due to grouting. Pressurized grouting of the soil nailing method is generally used in combination with ordinary portland cement and water. In the field, the cement is mixed with the rapid setting cement to reduce curing time because ordinary portland cement takes more than 10 days to satisfy the required strength. In this study, uniaxial compression tests and laboratory tests were carried out to confirm the efficiency of the grouting material according to the mixing ratio of rapid setting cement. The mixing ratio of 30% grouting satisfies the required strength within 7 days and satisfies the optimum gel time. As a result of the laboratory test with granite weathered soil, the reinforcing effect was confirmed to be 1.5 times as compared with the gravity type at an injection time of 10 seconds and a strain of 15%. The friction resistance increases linearly with the increase of the injection time, but it is confirmed that the friction resistance decreases due to the hydraulic fracturing effect at the injection time exceeding the limit injection pressure. Numerical analysis was performed to compare the stability of slopes not reinforced with slopes reinforced with gravity and pressurized soil nailing.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.1-10
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• 2018

We conducted research to develop a solidification agent for the ground surface reinforcement method in which activator is fused by recycling pig iron slag, which is a byproduct generated in the steel making process. The purpose of this research is to solve the problems of surface soil by improving the strength and durability of foundation soil such as soil loss, settlement, sinkhole, etc. by recycling pig iron slag from disused or landfilled steelworks. For this purpose, the possibility of using pig iron slag as a solidification soil was evaluated by the compressive strength, elution test of harmful materials, permeability coefficient test. As a result of the compressive strength test, the values of the strength of the curing 28 days of the solidified soil having the solidification agent mixing ratio of 12% were found to be 0.93, 0.96 and 1.3 MPa, respectively, satisfying the required strength value of 1 MPa, In the case of permeability coefficients, the minimum values were $4.1{\times}10^{-8}$, $7.0{\times}10^{-7}$, and $1.7{\times}10^{-7}cm/sec$, respectively, at the solidification agent mixing rate of 12%. In addition, as a result of the elution test of harmful materials, a small amount was detected in the item of hexavalent chromium but satisfied the inclusion criteria, and in the remaining items, heavy metals were not eluted.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.252-258
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• 2018

A larger energy consumption and concentration of population induced green house gas glowing and heat island effect in the urban space. Roof green system was a effect method to reduce green house gas and heat concentration in the city. Therefore, construction of this system was increasing. Most of lightweight soil used in roof green system was perlite, but this caused dust and skin disease. So it needed to develop another new lightweight soli for roof green system. Meanwhile, a thermoelectric power plant generated bottom ash as a by-product. According to previous research, bottom ash could be used for artificial lightweight soil with 60 wt% of mixing rate. But this study was proceed to develop a artificial lightweight soil using bottom ash with higher mixing rate by 65 wt% and different organic ingredients. First, physical and chemical properties of bottom ash was investigated. Then test according to landscaping design standard was proceeded for various artificial lightweight soil mix types using bottom ash, bark, compost and coco peat. As a result, the artificial lightweight soil with 65% of bottom ash, 30% of bark and 5% of compost was suitable for low and middle range of soil standard.

• Resources Recycling
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• v.27 no.5
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• pp.38-48
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• 2018

Deep cement mixing method (DCM) is used to improve the quality of various ground type and its technical development proceeding based on performance improvements of solidification materials and mixing techniques with ground soil. In this study, it was possible to improve silty clay ground soil had 1 to 3 MPa compressive strength using solidification material that composed mainly circulating fluidized bed combustion (CFBC) power plant fly ash and reduce standard deviation of strengths from over 1.0 MPa to 0.322 MPa using improved auger bits in field test to forming more uniform bulbs than in case of using existing auger bit.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.93-100
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• 2002

Vertical reinforcement of soft soils using the deep mixing method has received increasing applications. In this study, the theory of elasticity and plasticity including the upper bound theorem of limit analysis were used to derive the equations for obtaining composite elastic properties and shear strength parameters. The developed equations were validated using the finite element computer program SAGE CRISP. The analysis involved 4 different cases-two different type of soil and replacement ratios. Tile results of the analysis show that the proposed equations could determine the properties of composite material for practical applications.

• Geotechnical Engineering
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• v.1 no.2
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• pp.55-66
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• 1985

This paper is studied about the character of mixed soil which is applied lime and water-glass The effectiveness of mining such as cut-off effect and shear strength increasement of the chemically treated soils are investigated. For the main purpose of this study is to develope economical and practical method in chemical mixing method. The principal contents are described as follow. (1) Lime and water-glass series are used as chemical stabilizer and secondary additives in this experiment. (2) This study was analized and compared with engineering properties by the quantity of additives and by the character of chemical stabilizer. (3) And the effects of improvement in those treated soils are investigated as below; the increasement of shear strength, cut.off effect and consolidation character.

• Geomechanics and Engineering
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• v.28 no.1
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• pp.1-10
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• 2022

In Korea, accidents related to the collapse of deteriorated aging reservoirs occur every year. The grouting method is generally applied to reinforce an aging reservoir. However, when using this method, different reinforcing effects appear depending on the ground conditions. Thus, new construction methods and materials capable of providing consistent reinforcing effects are required. In this study, the direct shear test (DST), model test, and simulation analysis were performed to evaluate the impact of surface stabilizers, generally used to reinforce roads, rivers, and slopes of roads, applied using surface curtain walls on aging reservoirs. The DST results indicate that when the surface stabilizer was mixed with in-situ soil, the increase in cohesion was the highest at a mixing ratio of 9%. No changes in the friction angle were evident; therefore, 9% was determined to be the optimal mixing ratio. In addition, the model test and simulation analysis showed that when 9% of the surface stabilizer was mixed and applied to the aging reservoir, the seepage quantity of water and the saturated area were reduced by approximately 42% and 73%, respectively. Moreover, the comprehensive analysis of results showed that the grouting method could be completely replaced by surface stabilizers applied through surface curtain walls because the technique could secure stability by decreasing the seepage in the aging reservoir.

• Korean Journal of Environmental Agriculture
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• v.13 no.1
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• pp.83-89
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• 1994

The number of colonies often decreased more than would be expected in a dilution from 1:50 to 1:100; however, a lack of agreement between the dilution series and the number of colonies obtained also occurred at higher dilutions. In the experiments with each soil subsample, there was sometimes poor agreement between the number of colonies obtained at the same dilution from the A and B subsamples. However, repeated 1:50 dilutions of soil suspensions of subsamples A and B yielded similar numbers of colonies. In the second experiment series conducted with a second composite soil sample, the number of colonies obtained from each soil subsample decreased following air drying. The results suggest that it was difficult to obtain a uniform distribution of Pythium propagules in the two sugarcane field soils tested. The high number of propagules detected at the 1:50 dilution could have been due to hyphal fragments or connected hyphal swellings that separated during the final mixing or during plating.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5C
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• pp.229-237
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• 2009

A conventional way of backfilling has used sand or in-situ soil. It not only requires substantial amount of time and cost but also makes it particularly difficult to fill the bottom part and small cracks of a pipe. To address the problem with the conventional method of compaction, liquefied stabilized soil was proposed as an alternative because it reuses in-situ soil which can ensure sand supply while adjusting flowability and strength of the soil with design of mix proportion. With an aim to identify the mixing properties of liquefied stabilized soil depending on the organic content of in-situ soil, this study conducted indoor tests of material segregation, flowability, strength, and permeability by changing humic acid content of the soil. The results revealed that material segregation and flowability increased proportionally while strength decreased with the increased amount of humic acid. In the mean time, permeability of liquefied stabilized soil wasn't affected by organic content.