• Journal of the Korean GEO-environmental Society
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• v.17 no.2
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• pp.41-49
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• 2016

This paper evaluates the interface shear strength of HDPE textured geomembrane. The interface shear strength between textured geomembrane and marl, and textured geomembrane and woven geotextile were measured; and the smooth geomembrane was used to evaluate the effect of "texture" on the interface shear strength. The interface shear strength was measured using a large direct shear testing device under several conditions including the presence of water, and the normal stresses that were 12, 24, 45, 100, 500, and 1,000 kPa. From testing results, it was found that there was meaningful reduction in the interface shear strength in the presence of water, but the effect of normal stress was not clear. The interface shear strength was measured to be significantly different for smooth geomembrane, whose strength was measured to be as small as half that of the textured geomembrane.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.179-182
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• 2002

Geosynthetics are widely used in landfill for filtration, drainage, separation and so on. For many landfill failure cases, interfaces of geosynthetics can be potential failure surfaces. Therefore, it is very Important to estimate the interface properties of geosynthetics. In this study, shaking table tests were peformed between smooth geomembrane and geotextile. From the test results, it was found that there is a limited acceleration that can be transmitted from smooth geomembrane to geotextile. And the influence of normal stress and frequencies of excitation were discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.57-68
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• 1999

This paper summarizes the results of a study which uses the recently developed Optical Profile Microscopy technique (Dove and Frost, 1996) as the basis for investigating the role of geomembrane surface roughness on the shear mechanism of geomembrane/geotextile interfaces. The alternative roughness parameters which consider the direction of shearing are described. These directional parameters are compared with the existing roughness parameters, and the relationship between these directional and non-directional parameters are investigated. Then, the relationship between interface shear strength and surface roughness quantified at the interface is investigated. The results show that interface friction can be quantitatively related to the surface roughness of the geomembrane. The peak and residual interface strengths increase dramatically through the use of textured geomembranes as opposed to smooth geomembranes. For the smooth geomembranes, the sliding of the geotextile is the main shear mechanism. For the textured geomembranes, the peak interface strength is mainly mobilized through the micro-texture of the geomembrane, however, the residual interface strength is primarily attributed to macro scale surface roughness which pulls out and breaks the filaments from the geotextile. The results of this study can be extended to the other interfaces such as joints in rock mass, and also can be used to provide a quantitative framework that can lead to a significantly improved basis for the selection and design of geotextiles and geomembranes in direct contact.

• Journal of the Korean Geosynthetics Society
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• v.1 no.1
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• pp.3-11
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• 2002

The Geotextiles have been used for the protection of Geomembrane and the prevention of clogging phenomenon; however, the material can be easily damaged by construction equipments. It generally recommended to use at least $500g/m^2$ of Geotextile in Korea landfill, but few researcher were performed about the damage of Geotextile. Therefore, we intended to evaluate the potential damage of Geotextile by the traffic load simulating the final cover system in a field scale. Tensile strength and strain were appraised to understand the degree of damaged Geotextile. The tests were conducted under the condition of cross direction of Geotextile. Four different weight of Geotextile was used for the evaluation $500g/m^2$, $700g/m^2$, $1,000g/m^2$ and $1,500g/m^2$. The initial strain of $500g/m^2$ of Geotextile showed 50% that did not meet the standard 60%. The strain of $700g/m^2$ of Geotextile was below the standard after the traffic load test; however, the others met the requirement in the test. In conclusion, the weight of Geotextile used in landfill to protect the Geomembrane should be at least $700g/m^2$ in a view of strain requirement. We expect this study provides fundamental information for the construction of Geotextile in landfill.

• Journal of the Korean Geosynthetics Society
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• v.4 no.1
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• pp.37-46
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• 2005

PVA geotextile/HDPE geomembrane composites were made to examine the waste landfill related properties. Tensile properties, tear and bursting strengths, AOS(apparent opening size) and permittivity of PVA geotextiles were evaluated, respectively. Ultraviolet stability and chemical resistance to the leachate was evaluated also. Friction property and creep deformation were tested at various loading condition. From this, it was seen that PVA geotextile/HDPE geomembrane composites have more excellent properties than the typically used polypropylene and polyester geotextiles in waste landfill. Finally, creep deformation behaviours of PVA geotextile/HDPE geomembrane composites were more stable than polypropylene and polyester geotextiles through the reduction factor analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.255-262
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• 1999

This paper summarizes the results of a study which uses the recently developed Optical Profile Microscopy technique (Dove and Frost, 1996) as the basis for investigating the role of geomembrane surface roughness on the shear strength of goomembrane/geotextile interfaces. The results show that interface friction can be quantitatively related to the surface roughness of the geomembrane. The peak and residual interface strengths increase dramatically through the use of textured geomembranes as opposed to smooth geomembranes. For the smooth geomembranes, the sliding of the geotextile is the main shear mechanism. For the textured geomembranes, the peak interface strength is mainly mobilized through the micro-texture of the geomembrane, however, the residual interface strength is primarily attributed to macro scale surface roughness which pulls out and breaks the filaments from the geotextile. The results of this study can be extended to the other interfaces such as joints in rock mass, and also can be used to provide a quantitative framework that can lead to a significantly improved basis for the selection and design of geotextiles and geomembranes in direct contact.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.407-414
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• 2000

This paper presents measured deformation of geomembrane installed on slopes of a landfill. The layout of geosynthetics installed on landfill slopes as required by regulations is composed of, in typical, geocomposite, geomembrane, geosynthetic clay liner in turn from the slope. An effort was made to better understand the sources of external forces acting on geosynthetics and their interactions. The results of a field observation indicated that tensile stresses induced on geomebrane were far less in magnitude than predicted by the design method employing mass equilibrium of waste. This was mainly because external forces acting on slopes were not transferred from geocomposite to underlying geomembrane. A simple, but rather rational method for assessing the stability of geosynthetics against tensile stresses was proposed. This method is based on a hypothesis that external forces acting on geosynthetics are the results of downdrag of waste during waste compaction.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.501-510
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• 2003

Several geophysical surveys(electrical resistivity, electromagnetic, seismic refraction, CPR) were conducted to primarily investigate the gallery and the geomembrane at an abandoned mine(Imcheon mine). The subsurface structure mapped from seismic refraction survey mainly consists of three velocity layers(>1000 m/s, 1000∼2000 m/s,＜2000 m/s). Top of the bedrock, whose velocities exceed 2000 m/s, appears to be at depth of 7.5∼10m. Higher resistivities (of ten thousands-hundred of thousands ohm-m) are interpreted to be associated with a open(cavities) gallery. The events at depth of approximately 0.5∼0.7m in GPR sections are probably caused by high-density-poly-ethylene geomembrane. Taking into consideration of the differences in the spatial resolution between georadar and electrical surveys, the events of geomembrane correspond to the top of the high resistivities at depth of about 2m. The segments, characterized with the higher conductivities in the electromagnetic data and the lower resistivities in the electrical resistivity data, are probably associated with surface water or tear zone of geomembrane.

• Advanced Composite Materials
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• v.17 no.3
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• pp.235-246
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• 2008

This paper is concerned with geotextiles bonded chemically with geogrid to form a geocomposite. Geotextiles, thermally bonded and non-woven, play an important role as a separator. Also, this study investigates the resistance to the application environment of geotextile composites. Here, numerous tests have been performed and it was revealed from experimental results that thermally bonded geotextile in geosynthetic composites showed superior characteristics to that manufactured from needle punched non-woven method in terms of tensile strength, tensile strain and high separation performance. It was noted from experiments that the geotextile prepared for separation purpose and manufactured in a thermal bonding method showed relatively low permittivity so that it could be used as a smooth separator. In addition, PVA geotextile/HDPE geomembrane composites were designed and manufactured to investigate the waste landfill related properties. Numerous experiments have been performed and experimental results were summarized to evaluate practical applicability of PVA geotextile/HDPE geomembrane composites. Among the properties of proposed geomembrane composites, evaluation has been focused on the investigation of mechanical properties, AOS (apparent opening size), permittivity and ultraviolet stability.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.289-296
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• 2000

This paper summarizes the results of a study which has quantified the evolution of the structure of sands adjacent to geomembranes of varying roughness at different stages of shearing. The results show that the structure evolution, and hence shear mechanisms for rounded uniform sands adjacent to geomembranes, are directly influenced by the surface roughness of the geomembranes. For smooth geomembranes, the shear mechanism predominantly involves sliding of sand particles and only affects the sand structure within two particle diameters of the geomembrane. For slightly textured geomembranes, the effects of interlocking and dilation of sand particles extends the zone of evolution to four particles diameters from the interface. For moderately/heavily textured geomembranes, the interlocking and dilation of sand particles is fully developed and results in large dilation in the interfacial zone, which extends up to six particle diameters from the interface. By understanding how the structure of the sand adjacent to geomembranes of different roughness changes during shearing, it may be possible to identify alternative geomembrane roughening procedures and patterns that can lead to more efficient interface designs.