• Proceedings of the Korean Geotechical Society Conference
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• 1998.10a
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• pp.343-350
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• 1998

• 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.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.103-109
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• 1996

The cover liners at municipal and hazardous waste landfill is not emphasized as much as the bottom liners. However, one of the most effective reason of landfill destroy is the cover liner failure. The cover system at municipal and hazardous waste landfill, 1 perform the following functions, at minimum: promote surface runoff, impede infiltration, protect settlement in the landfill, and provide a buffer from surface exposure of the waste. This research was to expand the existing knowledge base of landfill cover liner behavior during period of freeze/thaw Also, the great Lysimeter was built in the laboratory to provide as much as same condition with the field and three designs were simulated by actual cover materials. The result of simulation indicated the clay was effected by freezing/thawing. The degradation of cover liners in the frost penetration affects the physical, engineering properties of clay. these factors may consider to design and construct of the landfill. This paper provides the description of testing cover liners, experimental results and a discussion of the results of the simulation.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.295-304
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• 2010

Performance of a landfill liner is evaluated based on leakage rate and mass flux. In this study, the recently utilized double composite liner system, which consists of a geomembrane (GM), a geosynthetic clay liner (GCL), a GM, and a compacted clay layer (61 or 91.5 cm) is compared with other popular composite liners including the single GCL system, the Subtitle D liner system, and the Wisconsin NR500 liner system. The leakage rate through circular and long defects in the GM of the landfill liners is analyzed using numerical models. For the mass flux criterion, the analyses of inorganic contaminant transport through defects in the GM component of liner systems and diffusion of organic compounds through intact landfill liners are conducted using three- and one-dimensional numerical models, respectively. Cadmium and toluene are used in the analyses as a typical inorganic and organic substance, respectively, which will be chemical species encountered during landfill operation. The comparison shows that the double composite liner systems are superior to the other liner systems according to the performance-based evaluation.

• Proceedings of the Korean Geotechical Society Conference
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• 1996.03a
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• pp.37-46
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• 1996

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.245-254
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• 2009

Efficiency of landfill liners system is usually evaluated based on leakage rate and mass flux. In this study, composite liner systems including the GCL(geosynthetic clay liner) composite liner, the Subtitle D liner, the Wisconsin NR500 liner, and the recently utilized double composite liner, which is a combination of the GCL composite liner and Subtitle D-type liner, have been examined. The leakage rate through circular and long defects in the geomembrane (GM) of the liner system was analyzed with the aids of analytical and numerical methods. For the mass flux criterion, contaminant transport through defects in the GM of landfill liners can be evaluated based on the calculated leakage rates. The diffusion rate of volatile organic compounds through intact landfill liners was evaluated by performing a one-dimensional numerical model. Cadmium and toluene were adoptted in the analyses as typical inorganic and organic substances, respectively, which will be chemical species encountered during landfill operation. The performance-based evaluation indicates that the double composite liner systems are superior to the other types of liner.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.273-280
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• 2003

This paper describes a study of the effect of shield tunnel construction on the liners of nearby existing perpendicular tunnels. The research programme investigated the influence of tunnel proximity and alignment, liner stiffness on the nature of the interactions between closely spaced tunnels in clay. A total of two sets of carefully controlled 1g physical model tests, including the same test for repeatability, were performed. A cylindrical test tank was developed and used to produce clay samples of Speswhite kaolin. In each of the tests, three model tunnels were installed in order to conduct two interaction experiments in one clay sample. The tunnel liners were installed using a model tunnelling machine that was designed and developed to simulate the construction of a full scale shield tunnel. The first tunnel liner was instrumented to investigate its behaviour due to the installation of each of the new tunnels. The interaction mechanisms observed from the physical model tests are discussed and interpreted.

• 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 Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.395-398
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• 2003

Geosynthetic Clay Liners(GCLs) have been widely used as hydraulic barrier in landfills and remediation projects of contaminated sites. The aim of this research is to modify GCLs for effective removal of contaminants. We perform the free swell test, hydraulic conductivity test, and contaminants (TCE, hexavalent chromium, and nitrate) removal test on the bentonite-ZVI mixture with various ZVI content. As the ZVI content increased, contaminants removal efficiencies and swell volume increased, and hydraulic conductivity decreased.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1090-1099
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• 2006

Tensile strength of soil is one of the important strength parameters in geotechnical engineering. The importance of the tensile strength of soil has been pointed out and given considerable attention in many highway pavements and earthfill dams. Recently, one of tensile strength problems, cracking failure of clay liners which is related to leakage of polluted water has been reported. Thus, the tensile strength of compacted sand-bentonite mixtures, which are used widely in the landfill construction site as clay liners was measured by Improved Unconfined Penetration (IUP) test. In addition, to find out the effects of contamination levels of water on the tensile strength and desiccation crack pattern, different pH levels of water were used for making specimens prepared with three different mixing contents of bentonite.