• Title/Summary/Keyword: geotextiles

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The Evaluation of Geotextiles by Ultraviolet(UV) Effect during the Landfill Construction (폐기물 매립지의 부직포 포설시 UV 영향에 대한 평가)

  • 고재학;이재영
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 1998.11a
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    • pp.206-215
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    • 1998
  • Using of geosynthetics with linear materials(sand, gravel, clay soil) is rapidly increased in landfill. With geosynthetics, geotextiles often expose to solar radiation(Ultraviolet) on long terms during the installation. In this paper, the results will represent the strength retention rate and tensile retention rate of geotextiles between outdoor exposed and protected by 15cm thickness of soil. As a result of cumulating solar radiation in geotextiles was increased, the strength retentions rate of P.P(500g/$m^2$), P.P(700g/$m^2$) and P.P(1000g/$m^2$) were decreased and the lower weight of unit area of geotextiles, the faster decrease of strength retention rate. P.E.T(600g/$m^2$) was showed a distinctive trend that the strength retention rate increased. The tensile retention rate of tested geotextiles was decreased during the simulation. However, the strength and tensile retention rate of geotextiles covered by soil had changed insignificantly. Therefore, it can surmise that the soil covering will help geotextiles to be protected from UV effecting

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Evaluation of Shear Strength at Interface Between Geotextile and Cementitious Binder Materials (시멘트계 결합재가 적용된 지오텍스타일의 접촉면 전단강도 평가)

  • Son, Dong-Geon;Byun, Yong-Hoon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.64 no.1
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    • pp.91-98
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    • 2022
  • Multi-layered geotextile tubes may have problems on its stability when used as cofferdam. This study presents the shear strength characteristics at the interface between geotextiles and a cementitious binder material to improve the stability of the multi-layered geotextile tubes. In this study, two different types of geotextiles are used. After mixing with a rapid setting cement, fly ash, sand, accelerator, and water, the cementitious binder material is prepared at the interface between two geotextile samples and cured under water for a desired period. The specimen is placed on upper and lower direct shear boxes by using clamping systems. A series of direct shear tests for two different geotextiles are performed along the curing time under three vertical stresses. Experimental results show that the shear strength at the interface between the cementitious binder material and geotextiles is greater than that at the interface between two geotextiles. For two types of geotextiles, apparent cohesion occurs at the interface between the cementitious binder material and geotextiles. In addition, the friction angles for any curing time are improved, compared to the interface between two geotextiles. The cementitious binder material suggested for the interface between two geotextiles may be useful for the reinforcement of multi-layered geotextile tubes.

Full-scale investigations into installation damage of nonwoven geotextiles

  • Sardehaei, Ehsan Amjadi;Mehrjardi, Gholamhosein Tavakoli;Dawson, Andrew
    • Geomechanics and Engineering
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    • v.17 no.1
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    • pp.81-95
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    • 2019
  • Due to the importance of soil reinforcement using geotextiles in geotechnical engineering, study and investigation into long-term performance, design life and survivability of geotextiles, especially due to installation damage are necessary and will affect their economy. During installation, spreading and compaction of backfill materials, geotextiles may encounter severe stresses which can be higher than they will experience in-service. This paper aims to investigate the installation damage of geotextiles, in order to obtain a good approach to the estimation of the material's strength reduction factor. A series of full-scale tests were conducted to simulate the installation process. The study includes four deliberately poorly-graded backfill materials, two kinds of subgrades with different CBR values, three nonwoven needle-punched geotextiles of classes 1, 2 and 3 (according to AASHTO M288-08) and two different relative densities for the backfill materials. Also, to determine how well or how poorly the geotextiles tolerated the imposed construction stresses, grab tensile tests and visual inspections were carried out on geotextile specimens (before and after installation). Visual inspections of the geotextiles revealed sedimentation of fine-grained particles in all specimens and local stretching of geotextiles by larger soil particles which exerted some damage. A regression model is proposed to reliably predict the installation damage reduction factor. The results, obtained by grab tensile tests and via the proposed models, indicated that the strength reduction factor due to installation damage was reduced as the median grain size and relative density of the backfill decreases, stress transferred to the geotextiles' level decreases and as the as-received grab tensile strength of geotextile and the subgrades' CBR value increase.

The Weatherability of Non-woven Geotextiles Used in Reinforced Earth Wall (보강토옹벽에 적용되는 지오텍스타일의 내후성)

  • 유중조;김영윤;전한용
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.419-424
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    • 2001
  • In the KOESWall system, non-woven geotextiles are placed at the face of reinforced earth until the facing blocks are built up. And when this system is used as temporary structure, geotextiles facings are exposed to sunlight during service lifetime. During these periods, degradation of nonwoven geotextiles are occurred by UV light. So the UV-resistance of nonwoven geotextiles must be assessed correctly, in considering of the site conditions. In this study, laboratory test and the field test have been performed to evaluate the UV resistance of non-woven geotextiles used in KOESWall system and the results are expressed in terms of tensile characteristics & SEM photographs.

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Geotextiles Horizontal Drain between Earth Fills and Natural Soft Ground (토목섬유를 사용한 무처리 연약지반과 성토사이의 수평배수층)

  • Lee, Hyoung-Kyu;Kong, Kil-Yong;Kim, Hyun-Tae
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.4
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    • pp.129-138
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    • 2002
  • This paper presents a study on the discharge capacity of geotextiles as a horizontal drain layer placed between the layers of earth fill and natural soft ground. Required discharge capacity of geotextiles as drain layers estimated by consolidation analysis is proportional to the consolidation coefficient of the ground soils and the width of the earth fills. The field discharge capacity of the geotextiles are measured by the hydraulic transmissivity test. And the results show wide variation according to the material characteristics of geotextiles, water content of the soils, vertical pressure, and etc. For the short horizontal drain length, geotextile filter mat can be used for the horizontal drain layer. And f3r the long drain($25{\sim}55m$), it is used for the drain together with Bord Drain.

Weatherability Assessment of Nonwoven Geotextiles by Field Exposure Test (현장노출시험에 의한 부직포 지오텍스타일의 내후성 평가)

  • Jeon, Han-Yong;Yuu, Jung Jo;Kim, Young Yoon;Byun, Sung Weon;Byun, Sung Weon
    • Journal of the Korean Geosynthetics Society
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    • v.3 no.1
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    • pp.37-42
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    • 2004
  • In the reinforced retaining wall system, non-woven geotextiles are placed at the face of reinforced earth until the facing blocks are built up. And when this system is used as temporary structure, geotextiles facings are exposed to sunlight during service lifetime. During these periods, degradation of nonwoven geotextiles are occurred by UV light. So the UV-resistance of nonwoven geotextiles must be assessed correctly, in considering of the site conditions. In this study, laboratory test and the field test have been performed to evaluate the UV resistance of non-woven geotextiles used in KOESWall system and the results are expressed in terms of tensile characteristics & SEM photographs.

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ENGINEERING PROPERTIES OF NATURAL FIBER USED NONWOVEN GEOTEXTILES (천연섬유 부직포 지오텍스타일의 공학적 특성)

  • Jeon, H.Y.;Jang, Y.S.;Lee, K.W.
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.267-272
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    • 2008
  • The purpose of this study is to improve the environmental applicability of nonwovens by using special composition. Polypropylene spunbonded and needle punched nonwovens which have the lower cost than polyester nonwovens were used as the raw materials to manufacture the natural fiber used nonwoven geotextiles. These geotextiles were made by use of the thermal bonding methods and composed of jute(or flax)/polypropylene staple fiber blends were obtained in consideration of environmental application. Finally, the engineering properties of natural fiber used nonwoven geotextiles were investigated as eco-friendly materials.

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Application on Geotextiles for the Roadbed Reinforcement of the Concrete Track Rehabilitation (콘크리트궤도 개량공사시 노반 보강을 위한 토목섬유의 적용)

  • Lee, Il-Wha;Jang, Seung-Yup;Han, Sung-Wu;Kim, Yong-Jin
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.1802-1806
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    • 2007
  • The most important factor is the roadbed bearing capacity at concrete track construction. Particularly, in case of rehabilitation, it is essential to secure the uniform roadbed stiffness to prevent the irregular settlement. In this study, reinforced effect of the geotextiles is investigated which is applied to concrete track rehabilitation. The geotextiles is installed two or three layers as the condition of the ground and structure. The reinforced effect of geotextiles is confirmed by the strain gage attached on the geotextiles surface.

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Evaluation of Long-Term Performance of Composite Geotextiles for Reinforcement (보강용 복합 지오텍스타일의 장기성능 평가)

  • Jeon, Han-Yong;Ryu, Jung-Jae;Lee, Su-Nam;An, Yang-Nim;Cho, Bong-Gyun
    • Journal of the Korean Geosynthetics Society
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    • v.2 no.2
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    • pp.33-38
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    • 2003
  • Polyester woven geotextiles to be bonded with nonwovens were manufactured for reinforcement and the allowable strength of these were obtained by the results of creep tests. Long-term design strength were calculated in consideration with factors of safety for design and construction and the long-term behaviors of geogrids were compared to those of composite woven geotextiles to examine the reinforcement function. From the experimental results, it was confirmed that these woven composite geotextiles could have the sufficient performance as an alternative geosynthetics instead of geogrids and the further study will be continue to confirm the possibility of woven composite geotextiles as the excellent reinforcing material.

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Studie8 on Long-Term Performance Evaluation of Geotextiles -for Filter and Drainage- (필터 및 배수용 토목섬유의 장기적 성능 평가에 관한 연구)

  • 권우남
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.35 no.3
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    • pp.130-139
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    • 1993
  • In order to evaluate the long-term permeability performace of the geotextiles, for five different combination of geotextiles and soils the long-term column test method The results obtained are as follows; 1.The gradient range of the initial stage of the long-term permeability curves varied with respect to the soil types, while that of the final stage varied according to the interaction of the soil/geotextile system. 2.The time required for a given soil/geotextile system to reach a interactive stable stage was measured ahout 100 hours for the standard sand and 150 to 600 hours for the silty content soils, respectively. 3.There were no differences between the plain woven geotextile and the non-geotextile in the long-term permeability performance. 4.As the silt content increased, the long-term performance of the geotextiles decreased, and the limiting silt content was about 15%. 5.The thickness and area density of the geotextiles did not influence on the variation of the seepage quantities. 6.The ayerage slope and the transition time of the long-time flow curve were calculated. 7.In order to evaluate the mechanism of soil/geotextile system more perfectly, the gradient ratio test or the hydraulic conductivity test is required.

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