• 한국지반환경공학회 논문집
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• 제17권2호
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• pp.41-49
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• 2016

본 논문에서는 HDPE 표면처리(textured) 지오멤브레인의 경계면 전단거동을 파악하고자 하였다. 표면처리 지오멤브레인과 marl, 그리고 직포(woven geotextile)와의 경계면에서 발생하는 경계면 전단강도를 측정하였으며, 표면처리의 영향을 파악하기 위해 매끈한(smooth) 지오멤브레인과 직포와의 경계면 전단강도를 측정하여 비교 분석하였다. 경계면 전단강도는 대형직접전단 시험기를 이용하여 측정하였으며, 다양한 조건에 대해 거동 변화를 알아보기 위해 수침조건과 수직응력을 변화시켰다. 시험에 사용된 수직응력은 총 6단계로 저압(12, 24, 45kPa)과 고압(100, 500, 1,000kPa)으로 구분하여 적용하였다. 시험결과 수침에 의한 경계면 전단강도의 감소는 유의미한 수준으로 나타났으며, 수직응력의 영향은 불확실했다. 표면처리 여부에 따라 경계면 전단강도는 큰 차이를 보여주었는데 매끈한 지오멤브레인의 경계면 전단강도는 표면처리 지오멤브레인에 비해 절반까지 감소하는 것으로 나타났다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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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.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 토목섬유 학술발표회 논문집
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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.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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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.

• 한국지반공학회논문집
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• 제16권3호
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• pp.89-89
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• 2000

The shear behavior of any interface is a function of the fundamental properties of both materials at the interface. This study aimed at investigating the effect of planar surface roughness on the stress-horizontal displacement curve at theinterfaces composed of various geomembrane textures and granular materials. In addition, the extent of surfacialscarring on smooth geomembranes against granular materials during shearing induced by plowing effect was studied. It wasobserved that the displacements required to achieve peak and residual interface resistance, and the stress-displacementcurve at the interface vary greatly with the surface roughness of geomembrane. Quantification of surface roughnessvariations on smooth geomembrane due to plowing effect showed that the surfacial scarring during shearing by the soilparticles is directly related to both the normal stress and the angularity of the soil particles at the interface. The findingsof this study can be used to provide the useful information for the design and selection of counterface materials.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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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.

• 폴리머
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• 제37권1호
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• pp.5-14
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• 2013

본 연구에서는 UVB-313(자외선 파장 290-315 nm) 노출 하에 smooth HDPE 지오멤브레인과 flexible PP 지오멤브레인에 대한 자외선 노출의 영향을 평가하였다. 인장특성, 용융지수, 표준 및 고압 산화유도시간 및 FTIR/ATR 결과들을 고찰하였다. 노출된 지오멤브레인 시료의 인장특성은 변하지 않았지만, HDPE 지오멤브레인보다 flexible PP 지오멤브레인의 경우 산화방지제의 감소가 더 큼을 알 수 있었다. 대표적인 현장온도 $20^{\circ}C$에서의 산화방지제의 수명을 예측하기 위하여 외삽에 의한 Arrhenius 모델을 적용하였다. 자외선 노출 전후의 HDPE 지오멤브레인 시료는 용융지수의 큰 차이는 없었지만 flexible PP 지오멤브레인은 가교발생으로 인한 용융지수 감소가 발생하였다. FTIR 스펙트럼으로부터 자외선에 노출된 시료의 경우 카르보닐기와 관련된 $1750\;cm^{-1}$ 부근에서 작은 피크가 발견되었으며, 이는 산화가 진행되었음을 예시하고 flexible PP 지오멤브레인의 경우 $3100{\sim}3500\;cm^{-1}$에서 하이드록시기 또는 하이드로퍼옥사이드기에 의한 새로운 피크를 확인할 수 있었다.

• Advanced Composite Materials
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• 제17권3호
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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.

• 한국지반신소재학회논문집
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• 제2권1호
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• pp.57-68
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• 2003

Strain-softening model is developed to characterize the interface behavior of geomembrane with geotextile and geosynthetic clay liner(GCL). The model proposed in this research is calibrated by using data from direct shear tests conducted on smooth and textured geomembrane. The research is divided into two regions, pre-peak and post-peak, to take into account of strain-softening effect. Although slight difference between measured and back calculated data is observed under high normal stress, good agreements, in general, are found from back calculations. Especially, good consistency is observed in the case of low normal stress. Based on the results, it can be concluded that the proposed model can be a reasonable constitutive law to figure out the behavior of strain-softening between interfaces of geomembrane. In addition, DSC(Disturbed State Concept) model is also presented for further application in geosynthetic interfaces.

• 한국지반신소재학회논문집
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• 제12권1호
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• pp.51-61
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• 2013

본 논문에서는 지오텍스타일 공극 크기 분포를 이미지 분석방법을 이용하여 정량적으로 산출하였다. 연구과정은 실내시험을 통해 지오텍스타일-지오멤브레인 층으로 된 재료를 에폭시 레진으로 포화시킨 후, 양생, 절단하여 그 표면을 디지털 광학현미경으로 관찰하고 정량화함으로 이루어졌다. 여기서는 재료공학에서 주로 사용하는 공간학(stereology)의 개념을 사용하였으며, 지오텍스타일 필라멘트에 의해 둘러싸인 공극의 크기를 최대내접공극크기분포(LIOS)로 표현하였다. 지오텍스타일 내부 축적빈도 50%에 해당하는 공극직경이 압축응력이 10kPa에서 300kPa로 증가함에 따라 $45{\mu}m$가량 감소하였으며, 다시 압축응력을 10kPa로 되돌렸을 경우 초기치의 90%정도 수준으로 회복하였다. 마찰형 지오멤브레인 표면에서 연직응력 100, 300 kPa을 받으며 전단되었을 경우 평균 공극의 크기가 각가 32, 16.5% 감소하였다. 본 논문의 시험 및 분석 결과는 지오텍스타일 내부의 최대내접공극 크기분포가 표면거칠기가 다른 지오멤브레인 표면에서 압축 및 인터페이스 전단됨에 따라 어떻게 변화하는지를 보여준다.