• Journal of the Korean GEO-environmental Society
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• v.6 no.4
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• pp.13-26
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• 2005

In this study, research results on organic and inorganic pollutant migration through single and composite liner were summarized. On the basis of these summarized research results, a design program for landfill liner, which can be used to optimize the liner thickness based on the allowable ground water criteria around the landfill subsurface, was developed. A reasonable liner thickness was obtained from the program output results, in the case of the migration of $Cl^-$ ion through a single clay liner. Therefore, the developed program could be used to carry out a preliminary design for landfill liners with respect to organic and inorganic pollutants.

• 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.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.283-299
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• 2001

The middle cover soils and clay liners collected from the Kumheung landfill in Gongiu City were analysed for As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Ti and Zn concentrations using 0.] N HCl digestion and total/sequential extraction experiments followed by ICP-AES determination. The uncontaminated soil and sediment samples were also analyzed for the comparison. The results of sequential extraction showed that Cu was dominant in the oxidizable fraction, and As, Ni, Sr, Ba, and Mn were in the exchangeable fraction. Zinc and Mn occurred mostly in association with reducible, residual and carbonate fractions. Most of Cd and Pb were bound to the reducible and oxidizable fractions. The main carrier of Co, Cr, Fe and 11 was the residual fraction and another important carrier was the reducible fraction. The percentage of the metals of organically-bound form in the middle cover soils and clay liner was in the order of Cu(48%) > Ti(42%) > Pb(27%) > As(25%) > Cd(20%). As deduced from sequential extraction analysis, potential order of metal mobility in the middle cover soils and clay liner from the landfill was proposed: Cd > Sr > As > Ni > Mn > Ba > Cu > Pb > Zn » Co > 11 > Fe > Cr. Based on the 'geoaccumulation index' and the 'enrichment factor' normalized to A], the level of contamination of Cu, Ni and C1' was significant in the samples from Kumheung landfill and surrounding farmland. Their enrichments were attributed partly to anthropogenic pollutions.

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.87-95
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• 2000

A series of consolidated undrained triaxial compression testes were performed to increase field applications of soil admixtures mixed with short fiber. Kaolin clay and three types of fiber were selected and auto cutter was used to obtain reliable length of fibers. Remolded soil specimens were tested for obtaining the basic data to be applied to the reinforcement of soft clay, embankment or barrier and clay liner of wastes landfill etc. Conversion equations from weight to volume of clay mixed with short fiber are introduced and relationships between fiber content and fiber concentration are derived. It is found that reinforcing effect by aspect ratio and mixing ratio of short fiber decreases as confining pressure increases. The best efficient reinforcing effect is given at the aspect ratio of 80~120 and the fiber content of 1.2%~2.4% and the fiber diameter of 0.27mm.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.3
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• pp.90-96
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• 2007

Modern waste management units, so-called "landfills" protect human health and environment from hazardous leachate and gas. Accordingly, it must be constructed with a bottom liner system that includes a gas collection layer. Leachate is the contaminated liquid that drains from the waste material pollutes ground water. For this reason. bottom liner system must have durability and low hydraulic conductivity (in case of compacted clay liner, no more than $1{\times}10^{-7}cm/sec$ ). P county in Kangwon province constructed a solid waste landfill with bottom liner system. In this study. it is mainly introduced that the test results on construction and quality control of bottom liner system by "Multiple composite liner construction technology", which is selected for bottom liner system in P solid waste landfill.

• Journal of the Korean Geosynthetics Society
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• v.5 no.4
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• pp.49-58
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• 2006

Recently, geosynthetic clay liners (GCLs) have increasingly been used to replace compacted clay liners (CCLs) in composite liner systems. Since the introduction of GCLs to waste containment facilities, one of the major concerns about their use has been the hydraulic equivalency to CCLs as required by regulations. Laboratory test results and more recently field observations show that the thickness, or mass per unit area, of hydrated bentonite in a GCL can decrease under normal stress, especially around zones of stress concentration or nonuniform stresses, such as a rock or roughness in the subgrade, a leachate sump, or wrinkles in an overlying geomembrane. This paper presents field case histories that confirm the laboratory observations of bentonite migration and the effect of bentonite migration on hydraulic equivalency and contaminant transport through a GCL.

• Proceedings of the Korean Geotechical Society Conference
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• 1995.06b
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• pp.88-116
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• 1995

The applicability of marine clay and banking material as landfill liner and supporting layer was examined, where additives (cement, lime, Mg0, bentonite and ESCA) were mixed with these soils. The mixtures were tested for the unconfined compressive strength, bending strength, permeability, and better results than existing solidifying agents were obtained. The freezing-thawing test is under way.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.97-106
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• 2007

In this study, experiments are conducted to find out the effect of waste leachate on landfill clay liner system. Tensile test, hydrometer analysis and crack pattern test were conducted on sand-bentonite mixtures with different pH values of water. The tensile strength of specimen compacted with pH 9 of water is smaller than that of specimen compacted with for pH 3 and 6 of water. That is, the higher the pH value, the smaller the tensile strength, because a higher pH solution decreases flocculation phenomenon. The percent finer also increased with high pH value in particle size distribution of fine grained soil (<0.075 mm), because the velocity of particles settling decreases. This trend becomes the clearer as the content of bentonite, becomes the larger, because the higher pH value decreases flocculation structure of fine soils. The results of the crack pattern tests also showed the effect of pH values of water.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.41-51
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• 2002

Recently, domestic waste landfills are constructed sometimes on seashore area to provide large landfill area. In order to strengthen the foundation of landfills and to prevent the infiltration of leachate through the bottom, many cases of constructing cement hardened liners on seashore clays are found. In these cases, it is possible to have cracks in the hardened liners due to settlement with waste load since the stiffness of the hardened liner Is greater than that of clay liners. In this study, the capability of Self-Sealing and Self-Healing (SSSH) liner made with a seashore clay in the metropolitan landfill to prevent the percolation of water and leachate is examined using flexible-wall permeameter test and using uniaxial compression test. Applicability of SSSH to weathered granitic soil is also examined for self-sealing capabilities. The result of Flexible permeameter test for SSSH with the seashore clay showed that permeability obtained was lower than permeability criteria of Korean waste management law. The permeability and strength characteristics of SSSH with granitic soil and bentonite showed better results than with the seashore clay.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1412-1419
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• 2005

Preventing the infiltration of rainwater into the landfill site is the main purpose of the final cover in landfill sites. Compacted clay layer or geomembrain have been used as a conventional landfill final cover. But they have several disadvantages when damages might occur due to puncturing, differential settlement and desiccation or freeze and thaw. For this reason, as an alternative method SRSL(Self Recovering Sustainable Liner) has been developed. Adopting the precipitation reaction of two chemical material, by forming precipitates that fill the pores, and lower the overall permeability of the liner. The advantage of this method is that when fracture of the liner occurs the remaining reactants of the two layers form precipitates that fill the fracture and recover the low permeability of the liner. In this study, the recovering ability of the SRSL with a crack due to the seasonal variation or differential settlements was investigated by permeability tests. And in order to estimate the durability of the SRSL after freeze/thaw and desiccation, uniaxial compression strength tests were performed.