• Title/Summary/Keyword: 섬유보강토

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Characteristics of compaction and strength for synthetic fiber reinforcement soils (섬유 보강토의 다짐 및 강도 특성)

  • 송창섭;장병욱;이용범;임성윤
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1998.10a
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    • pp.444-448
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    • 1998
  • This paper presents the results of an experimental investigation on the compaction and compressive strength of polypropylene fiber reinforced soils. This study has been performed to obtain the physical properties of PFRS(polypropylene fiber reinforced soil) such as strain-stress relationships, OMC(optimum moisture contents) and ${\gamma}$$_{dmax}$ (maximum dry unit weight), with four different concentrations(i.e., 0.1%, 0.3%, 0.5% and 1.0% weights) of mono-filament and fibrillated polypropylene fibers. The test results indicate an appreciable increase in strength due to addition of fibers. OMC is increased with the concentration ratio of fiber, but ${\gamma}$$_{dmax}$ is decreased. From the viewpoint of strength, the fibrillated polypropylene fiber soil is more effective than the mono-filament polypropylene fiber soil.oil.

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A study on the crack characteristics of the Synthetic Fiber reinforced Soil (섬유 보강토의 균열 특성 연구)

  • 송창섭;이신호;반창현;인현식
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1998.10a
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    • pp.431-437
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    • 1998
  • This study was performed to ascertain the three-dimensional effect of the crack reduction and the restrained effect of crack growth, and to yield a suitable mixing ratio of the synthetic fiber reinforced soil. The results of the study are as follows ; 1) The synthetic fiber has the resisting force for crack because of the adhesion due to the attraction of soil particles. 2) As the synthetic fiber length and the mixing ratio are increased, mono filament synthetic fiber reinforced soil is increased the effects of crack reduction and the restraint of crack growth. 3) The fibrillated synthetic fiber is more effective than mono filament synthetic fiber for crack. 4) A suitable mixing ratio of synthetic fiber reinforced soil is 0.5% of the fibrillated synthetic fiber.

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Evaluation of Weathered Granite Soil l Geogrid Friction Properties and Pull out Test (화강 풍화토/지오그리드 인발시험 및 마찰특성 평가)

  • 조삼덕;김진만
    • Geotechnical Engineering
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    • v.12 no.4
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    • pp.87-100
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    • 1996
  • The pull -out test has been used to investigate the friction properties between soil and grid type geosynthetics which is useful to measure the passive bearing resistance as well as the skin friction. In this paper, the friction properties between geogrid and a weathered granite soil are investigated by performing various pull-out tests. From the test results, a rational pull out test equipment and test method is suggested by evaluating the effects of major factors (such as geogrid width, location of soil box facing, vertical loads and pulll -out displacement rate, etc.) on pull -out test results.

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A Study on Shear strength and Friction Properties of Fiber-Mixed Soil as Backfill Material in Reinforced Earth Wall (섬유혼합 보강토의 전단강도특성 및 마찰특성 연구)

  • 조삼덕;김진만;안주환
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.651-658
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    • 2002
  • A series of experimental study are performed to evaluate the shear strength and friction properties of fiber-mixed soil as backfill material in reinforced earth wall. In order to evaluate the properties of shear strength the big-size direct shear tests are carried out and on the friction properties, the shear friction tests and the pull-out tests are performed. In the results, when the mixed ratio of the net type fiber is 0.2%, the reinforcement effect was better than the others. Also the reinforcement effect of the net type fiber was larger than that of the line type fiber.

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Current State and Technical Development of Geosynthetics-Reinforced Earth Wall (토목섬유 보강토옹벽의 기술현황 및 개발동향)

  • Cho, Sam-Deok;Lee, Kwang-Wu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.141-157
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    • 2008
  • Since 1984, block-type reinforced earth wall with geogrid reinforcement has been widely used for retaining wall applications till now in Korea. The use of geogrid as a reinforcement in the reinforced earth wall is steadily increased in an amount over $6,500,000m^2$ in a year. However, still need exists that some problems in design and construction practices should be made to review. Therefore, this paper reviewed current state and development items of geosynthetics-reinforced earth wall technology on design and construction point of view.

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Flexural Performance of Cement Treated Clay-Sand Mixtures Reinforced with Synthetic Fibers (합성섬유로 보강된 시멘트-점토-모래 혼합토의 휨성능 평가에 관한 연구)

  • Jung, Du-Hwoe;Cho, Baik-Soon;Lee, Yong-Yun
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.1
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    • pp.19-29
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    • 2017
  • The effects of synthetic fibers, cement content, and sand content on the flexural performance of cement-clay-sand mixtures has been evaluated through a flexural performance test with a third-point loading. Beam specimens for the flexural performance test were fabricated with a various amount of cement, sand, and synthetic fibers. Two types of fibers, PVA (Polyvinyl alcohol) and PP (Polypropylene) fibers, were employed in the test. The test results have exhibited that the factors considered in the test have significant effects on the flexural performance of the mixtures in several aspects. The flexural performance of the mixtures has been improved if the mixtures were reinforced with synthetic fibers. The flexural strength and the flexural toughness of the mixtures has been increased as the fiber content was increased. A multiple linear regression analysis has been performed to evaluate the effect of fiber content, cement dosage, and sand content on the flexural performance of the mixtures in terms of flexural strength and flexural toughness. Cement content and sand content were estimated as important factors to have an influence on the first-crack strength and the peak strength whereas the fiber content has the most significant influence on the post-crack behavior. The first-crack strength and the ultimate strength were increased as the cement content and the sand content were increased. As the fiber content was increased, the flexural toughness was increased.

A Study of the Measurement of Nonwoven Geotextile Deformation with Strain Gauges (스트레인 게이지를 이용한 부직포의 변형거동 계측에 관한 연구)

  • Won, Myoung-Soo;Kim, You-Seong;Kim, Hyeong-Joo;Park, Byung-Soo
    • Journal of the Korean Geotechnical Society
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    • v.23 no.4
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    • pp.25-32
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    • 2007
  • Because of the increasing use of clayey soil as the backfill in reinfurced soil structures and embankments, nonwoven geotextiles of drain capability have been receiving much attention. However, there are few studies on the deformation behavior analysis of nonwoven geotextiles in reinforced soil structures in the site because nonwoven geotextiles which have low tensile stiffness and higher deformability than geogrids and woven geotextiles, are difficult to measure their deformation by using strain gauges. In this study, it was suggested that a new and more convenient method could measure the deformation behaviour of nonwoven geotextile using a strain gauge and examine the availability of the method by conducting laboratory tests and applying to two geosynthetics reinforced soil (GRS) walls in the site. The result of wide-width tensile test conducted under confining pressure of 70 kPa shows that the local deformation of nonwoven geotextile to be measured with strain gauges has a similar pattern to the total deformation measured with LVDT. In the GRS walls, nonwoven geotextile shows a larger deformation range than the woven geotextile and geogrid. However, the deformation patterns of these three reinforcement materials are similar. The function of strain gauges attached to nonwoven geotextile in the walls works normally for 16 months. Therefore, the method proposed in this study for measuring nonwoven geotextile deformation using a strain gauge has proved useful.

A Fundamental Study on Behavior Characteristics of the Geosynthetic Composite Reinforcement in the Weathered Granite Backfill Soils (화강풍화토 뒤채움흙 내부 토목섬유 복합보강재의 거동특성에 관한 기초연구)

  • 김홍택;김승욱;전한용;이인모
    • Journal of the Korean Geotechnical Society
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    • v.15 no.5
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    • pp.171-191
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    • 1999
  • The final aim of this research is to systematize the reinforced-earth wall system using the geosynthetic composite reinforcement in the weathered granite backfill soils having relatively large amount of fines. As a staged endeavour to accomplish this purpose, laboratory pull-out tests and finite element modeling are carried out in the present study focusing on the analyses of friction characteristics associated with interaction behaviors of the geosynthetic composite reinforcement composed of geogrid with a superior function in tensile resistance and geotextile with sufficient drainage effects. In addition, drainage effects of the geotextile below geogrid are examined based on the analysis of finite difference numerical modeling. From the present investigation, it is concluded that the geosynthetic composite reinforcement in the weathered granite backfills may possibly be used to achieve effects on both a reduction of deformations and an increase of the tensile resistance, together with drainage effects resulting from the geotextile.

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Slope Stability Analysis Considering Reinforcing Effects of Geosynthetics (토목섬유의 보강효과를 고려한 사면안정해석)

  • Kim, Kyeong-Mo;Kim, Hong-Tack;Lee, Hyung-Kyu
    • Journal of the Korean GEO-environmental Society
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    • v.6 no.1
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    • pp.73-82
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    • 2005
  • Generally, to evaluate a slope stability of the geosynthetic reinforced soil slope, the modified version of limit equilibrium method can be used. In most cases, resisting effects of reinforcement are dealt with considering an increased shear strength on the potential slip surface. However, it is not clear that the methods satisfy all three equilibrium equations. In this study, the new slope stability analysis method in which not only reinforcing effects of geosynthetics can be considered but also all three equilibrium equation can be satisfied is proposed. A number of illustrative examples, including published load test of large-scale reinforced retaining wall and centrifuge model tests on the geotextile reinforced soil slopes, are also analyzed. As a result, it is shown that the newly suggested method produces a relatively accurate factor of safety.

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Geosynthetic Reinforced Soil Method for Restoration of Debris Flow Failure Slopes (쇄설성 유동파괴 사면 복구를 위한 토목섬유 보강토 공법)

  • Cho Yong-Seong;Kim You-Seong;Park Inn-Joon
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.93-101
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    • 2005
  • The formation of slopes is unavoidable under the special circumstance of Korea where $7%$ of the whole area are composed of mountains and civil engineering projects such as road and site developments are increasing with industrial development and horizontal expansions of urban area. Stability of slopes is one of quite important issues under special meteorological characteristics that over two-thirds of annual average rainfall is concentrated in summer season and the localized torrential downpour is getting more frequent recently. As a result of these circumstances, partial slope failures by debris flow of the high water content soils occur frequently in cut soil slopes. In this case of debris flow slope failure, slope declination method is selected fur the stable recovery because it is impossible to recover entirely by existing recovery methods. Seeding or special grass planting methods are followed separately without exception. The method by which entire recover with bigger stability ratio would be possible and grass planting work would be done simultaneously is developed. For debris flow failure slopes, this study secured the safety of slopes by preventing the inflow of rainwater and scour using geosynthetics-reinforced embankment, and created nature-friendly slopes by planting trees on the slopes.