• Applied Biological Chemistry
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• v.20 no.2
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• pp.255-261
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• 1977

Using tracer technique of Zn-65, a pot experiment has been carried out in order to evaluate the efficiency of zinc fertilization on two paddy soils; an acidic from Kimpo and an alkaline from Yeongweol. The sources of zinc were zinc sulfate, zinc carbonate, zinc chloride and zinc oxide. Two rates of zinc were applied to the soils and control treatment was also included for this study. The methods of zinc application were uniform mixing throughout the soil, applying to the soil surface and irrigation water, and root dipping with zinc oxide at transplanting. In general, Yeongweol soil had higher efficiency of zinc fertilizers than Kimpo soil. The results showed that zinc fertilizer application should be required to improve the rice growing conditions in Yeongweol soil especially at early stage of growth after transplanting. As to the application method of zinc fertilizers, mixing treatment appeared to be most superior to any other methods in both soils. In addition, it is found that root dipping in the zinc oxide suspension would be a rather effective method of zinc application. In aspect of fertilizer efficiency there was no superiority or inferiority among the zinc sources used in this experiment.

• Journal of the Korean Geotechnical Society
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• v.25 no.8
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• pp.47-55
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• 2009

This research has the purpose to examine the potential of shell, a byproduct of maritime products to be utilized as alternative environment-friendly construction material by mixing and applying it with residual soit which is used as burial or filling material to recycle it. To that end, the research looked into the mechanical characteristics of shell through cyclic triaxial test by mixing it with residual soil. With the mixing ratios of shell of 5 groups set at 5.0%, 10.0%, 20.0%, 40.0% and 60.0%, the mixture soils was processed through a series of cyclic triaxial tests. And it was shown that liquefation resistance has limitation in the mixed soils with shell substitute content ratios exceeding 20.0%. To increase the liquefaction resistance of the mixed soil, this research has shown that addition of moderate amount of glass fibers would suffice.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.63-73
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• 2019

In this study, it was studied recycled soils with bentonite-polymer mixture in order to design economic landfill instead of clay liner. Recycled soil was used as SP, a sandy soil with 90.58% sand and 1.88% silt and clay. The recycled soils were mixed with 4%, 6%, and 8% bentonite by weight, and then compared with samples mixed with 2%, 3%, and 4% bentonite by weight in marine clay. Recycled soil satisfied the permeability criteria at 8%, and clay soil satisfied at 3%. In order to make a sample that satisfies the standard of the waste landfill, a permeability test was conducted by mixing 0.16%, 0.24%, and 0.28% of the polymer in a sample having 4% bentonite mixing ratio. The unconfined compression strength test was carried out at the same mixing ratio to confirm that the specification was satisfied. As the bentonite mixture ratio increased, the permeability coefficient and unconfined compression strength decreased. The strength in polymer mixing increased initially and then maintained a constant value. At 4% bentonite mixing ratio and 0.28% polymer mixing ratio, the coefficient of permeability was 1.0×10^-7 cm/sec or less, and the unconfined compression strength was over 500 kPa. It was confirmed that it can be used as a mixed liner material of waste landfills.

• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.7-15
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• 2006

In this research, the behavior characteristics of cement mixing lightweight soil (CMLS) for recycling of dredged soil in the Nakdong River estuary are experimentally investigated. CMLS is composed of the dredged soil from Nakdong River estuary, cement, and air foam. For this purpose, uniaxial compression tests are carried out for artificially prepared specimens of CMLS, with various initial water contents, cement contents, and mixing ratio of dredged soils. The experimental results of CMLS indicated that the compressive strength is strongly influenced by the cement contents, rather than water contents and air foam. Compressive strength of CMLS increased with an increase in cement content, while it decreased with an increase in water content and air foam content. It was also found that the modulus of deformation E50 was in a range of 44 to 128 times greater than the value of uniaxial compressive strength, cured in 28 days.

• Economic and Environmental Geology
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• v.33 no.4
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• pp.273-282
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• 2000

In order to investigate the extent and degree of arsenic and heavy metal contamination and the bioavailability of toxic elements around the abandoned mine in Korea, an environmental geochemical survey was undertaken in the Daduk mine. After appropriate preparation, tailings, soil, stream sediment, crop plant and fingernail samples were analysed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of 8,782 mg/kg As, 8.3 mg/kg Cd, 489 mg/kg Cu, 3,638 mg/kg Pb and 919 mg/kg Zn were found in tailings from the Daduk mine. These significant concentrations can impact on soils and sediments around the tailing ponds. Mean concentrations of As, Cd, Pb, Cu and Zn in soils are significantly higher than those in world average soil, especially for As and Pb. Element concentrations in sediments decrease with distance from the tailing ponds due to a dilution effect by the mixing of uncontaminated sediments. Arsenic and Cd are elevated in rice grains and stalks, and Cu and Zn concentrations in chinese cabbage, sesame and bean leaves are higher than the upper limit values for normal plant. Arsenic concentration in fingernails of farmers are higher than the normal level with a maximum value of 1.5 mg/kg. The post-ingestion bioavailability of toxic heavy metals in some paddy and farmland soils has been also investigated using the SBET (simple bioavailability extract test) method. The method utilises synthetic leaching fluids closelyanalogous to those of the human stomach. The quantities of As, Cd, Cu, Pb and Zn extracted from paddy soils after 1 hour indicated 15.9, 65.4, 46.2, 39.4 and 29.4% bioavailability, respectively and for farmland soils, 12.4, 26.0, 31.2, 29.3 and 19.4% bioavailability, respectively. The results of the SBET indicate that regular ingestion of soils by the local population could pose a potential health threat due to long-term toxic element exposure.

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

• 연구논문집
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• s.34
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• pp.1-10
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• 2004

Landfill Mining is becoming more widely used in many closed landfill sites in the world. Many of existing landfills will be excavated inevitably owing to building the clean environment with the new structures and developing the cities in cramped country. This paper aimed at the introducing the design technology of the trommel screen and its in-site applied performance of the trommel screen system through experiments , which system is under developing by one of the national project and the analysis results of influencing factors to the environment . The result of the theoretical estimation agrees well with the experimental data, so that the sorting system could be able to be applied with the requirements of the purpose of end-items. As a result of the analysis, any hazardous materials including heavy metals met the limitions of the criteria in this experiment. In geotechnical enngineering, it will. desireable to use the sorted soils mixing with another soils in accordance with the requirements of the usages.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1206-1211
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• 2010

Soil-cement, a hardened mixture of Portland cement, soil, and water that contain sufficient durability, has been widely utilised in Seoul urban construction sites to retain lateral earth pressures or reinforce grounds. However, little information has been reported about the strength characteristics of soil-cement constructed in Seoul urban area. In this study, we performed a number of unconfined test to the soil-cements mixed from soils sampled in 3 sites in Seoul urban area. Results indicate that unconfined strengths and optimum cement amounts of soil-cements are highly dependent on the proportion of coarse-grain particles of mixed soils. Furthermore, changes of unconfined strengths with curing time are diverse with respect to mixing conditions.

• Journal of the Korean Geotechnical Society
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• v.16 no.2
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• pp.79-89
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• 2000

The application of stabilization method has increased because of short construction periods, no environmental problems with dumped and replaced soil, assurance of required strength and economical effect with mid to small size construction. The unconfined and triaxial(UU-condition) compression tests were executed with each mixing sample for the study of the improvement effects and the effect of design-parameters by the stabilization methods. Three typical stabilizers, which are representative in Korea, were applied in this study, and three common soils(very soft clay, general weathered soil, common clay), which are common in Korea, were used in this study. In this study, the effect of engineering factors(soils, stabilizers and water contents, etc.) which are important parameters for the improvement effects of mixed ground by stabilizers, was analyzed. As results, the tendencies of design-parameters(unconfined compression strength, deformation modulus and strength parameter) are presented and the criteria of the application of stabilization methods are suggested.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.59-70
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• 2005

A series of resonant column test was performed to investigate the dynamic deformation characteristics of silty sand soils mixed with polypropylene fibrillated type fiber. Results show that optimum mixing ratios were $0.2\%$ for 19mm of cut fiber for shear modulus and $0.1\%$ for 60mm cut fiber fur damping ratio. As shear strain was increased, normalized values of shear modulus (G(Reinforced)/ G(Unreinforced)) of fiber reinforced soil were increased up to $10^{-3}\%\~10^{-1}\%$ ranges. However, normalized damping ratio (D(Reinforced/D(Unreinforced)) was diminished with an increase in strain beyond $10^{-3}\%\~10^{-1}\%$ for the damping capacity of soils mixed with fiber. Normalized shear modulus $(G/G_{max})$ obtained from the test was plotted in the chart suggested by Seed and Idriss. The shear modulus of silty sand was located between sand and gravel curves.