• Title/Summary/Keyword: 섬유보강토

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A Study on the Failure Behavior of Overhanging Geosynthetic-Reinforced Soil Structure Considering Dilatancy Characteristics of Compacted Soil (다짐토의 다일러턴시 특성을 고려한 역경사형 토목섬유 보강토 구조물의 파괴 거동 분석)

  • Kim Eun-Ra;Kang Ho-Keun
    • Journal of the Korean Geotechnical Society
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    • v.20 no.9
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    • pp.65-75
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    • 2004
  • In this paper, a mechanism of the soil structure reinforced by geosynthetics is discussed. The reinforcing mechanism is interpreted as an effect arising from the reinforcement works preventing the dilative deformation (negative dilatancy) of soil under shearing. A full-scale in-situ model test was carried out in Kanazawa of Japan (1994), and in the laboratory test the strength and the characteristics of deformation conducting a constant volume shear test are examined. The parameters needed in the FEM are also applied by using the experimental data. The elasto-plastic finite element simulation is carried out, and the results are quantitatively compared with that of experiment. As a results, it is known that the theoretical predictions could explain effectively the experimental results which are obtained by a full-scale in-situ model test.

An Application of Elasto-Plastic Model to Overhanging Geosynthetic-Reinforced Soil Structure (역경사형 토목섬유 보강토 구조물에 탄소성 모델의 적용)

  • Kim, Eun-Ra;Iizuka, Atsushi;Kim, You-Seong
    • Journal of the Korean Geosynthetics Society
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    • v.3 no.4
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    • pp.3-12
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    • 2004
  • In this paper, a mechanism of the soil structure reinforced by geosynthetics is discussed. The reinforcing mechanism is interpreted an effect arising from the reinforcement works so as to prevent the dilative deformation (negative dilatancy) of soil under shearing. A full-scale in-situ model test was carried out in Kanazawa of Japan(1994) and in the laboratory test the strength and the characteristics of deformation conducting a constant volume shear test are examined. The parameters needed in the FEM are also applied by using the experimental data. The elasto-plastic finite element simulation is carried out, and the results are quantitatively compared with that of experiment. As a results, it is known that the theoretical predictions could be explained effectively the experimental results which are obtained by a full-scale in-situ model test.

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Shearing Properties of Fiber-Reinforced Soil (섬유혼합 보강토의 전단특성)

  • 조삼덕;김진만
    • Proceedings of the Korean Geotechical Society Conference
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    • 1993.10a
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    • pp.23-28
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    • 1993
  • Shearing properties of soil reinforced with discrete randomly oriented inclusions depend on soil density, particle size, grading, fiber length, tensile strength and stiffness of fiber, mixing ration of fiber, confining stress, etc.. In this paper the effects of those various factors on shear strength of the fiber-reinforced soil was evaluated through triaxial tests and uniaxial tests. Tests were performed on two sandy soils and one silty soil with inclusions in varing lengths, contents and tensile strengths and tested at different confining stresses in triaxial test. From the experimental results, it was investigated if there is an optimal range of fiber lengths and fiber contents for the tested soils.

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A Study on the Characteristics of Behavior of Block-type Reinforced Earth Retaining Wall Considering Failure Surface (파괴면을 고려한 블록식 보강토 옹벽의 거동 특성 연구)

  • Yoon, Won-Sub;Park, Jun-Kyu;Chae, Young-Su
    • Journal of the Korean Geosynthetics Society
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    • v.15 no.3
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    • pp.13-26
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    • 2016
  • In this study, more economical than conventional reinforced soil retaining walls, we compared the behavior characteristic about the safety block type numerically for reinforced retaining wall. In this study, reinforced soil retaining wall, first, was integrated a wall putting shear key on the blocks. Second, construction reinforcement focused on the theoretical failure surface was satisfied with the stability of a retaining wall reinforced by a shear plane. when analyzing, element of using reinforcement was carried out a numerical analysis for the cable element and the strip element, and they were analyzed under the conditions according to the stiffener length, distance, with or without shear key. Analysis for the integration of the front wall was reinforced soil retaining walls by installing a larger displacement shear key confinement effect, if reinforced construction and reinforcement with 1 interval and 2 interval, the failure surface was bigger displacement constraints. Generating a deformation amount was smaller than the generation amount of deformation accrued during construction of AASHTO so that it was stable.

An Analysis of the Internal Deformation Behaviors of Geosynthetic Reinforced Soil Walls used Clayey Soil as Backfills (뒤채움재로 점성토를 사용한 보강토벽의 내적 거동 분석)

  • Kim, Heung-Ki;Kim, You-Seong
    • Journal of the Korean GEO-environmental Society
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    • v.6 no.2
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    • pp.39-49
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    • 2005
  • In this study, the fifteen month behavior of two geosynthetic reinforced walls which was constructed on the shallow weak ground was measured and analyzed. The walls were backfilled with clayey soil obtained from the construction site nearby, and the safety factors obtained from general limit equilibrium analysis were less than 1.3 in both wall. The measured and analyzed data were horizontal earth pressures, strain of reinforcements, and excess pore water pressures. The used reinforcements were nonwoven geotextile, woven geotextile and geogrid. Although the length of reinforcement was only 30% of wall height and the safety factors of the walls were less than 1.3, the walls were constructed without any problems on the such weak ground. The analysis results showed that the maximum strain of reinforcements were negligible and the strain was between 2.3 and 6.0% according to tensile characteristic of the reinforcements. The excess pore water pressure was not changed due to the rainfall and the horizontal earth pressures in upper and lower part of the walls were larger than the active and the rest pressure.

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Case Study on the Countermeasure Methods and Collapsed Sources of Segmental Retaining Wall Considering Site Conditions (시공환경을 고려한 블록식 보강토옹벽의 붕괴요인 분석 및 대책방안 사례연구)

  • Han, Jung-Geun;Cho, Sam-Deok;Jeong, Sang-Seom;Lee, Kwang-Wo;Kim, Ji-Sun
    • Journal of the Korean Geosynthetics Society
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    • v.4 no.3
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    • pp.35-43
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    • 2005
  • The geosynthetic reinforced segmental retaining walls(SRW) are improved that the disadvantage of existed retaining wall and the workability in field. Recently, the segmental retaining wall is replacing the exited wall because it is quickly advanced to using by the block in-situ. The use, therefore, is increasing. But, the trends of the large scaled construction was developed that the problems likely to crack and collapse, those are caused of careless in design and construction of SRW not considering about various surrounding conditions. In this study, the cause analysis on destructed SRW was carried out that based on the datum of measured displacement of walls, rainfall features and ground sounding conditions. Also, the analysis of the global slope stability was carried out on collapsed section and non-collapsed section using critical equilibrium method. For the rational stability and analysis of slope including SRW structure, the site conditions including situations of topography, ground and histories of construction and collapse etc should be considered. The rational countermeasure methods for non-collapsed and collapsed areas may be sustained as much as possible current state.

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Assessments of Creep Properties of Strip Type fiber Reinforcement (띠형 섬유보강재의 크리프 특성 평가)

  • 전한용;유중조;김홍택;김경모;김영윤
    • Journal of the Korean Geotechnical Society
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    • v.19 no.2
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    • pp.279-289
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    • 2003
  • Geosynthetic reinforced earth wall was introduced about 20 years ago and many structures have been constructed. Especially, segmental concrete panel facing and friction tie system are the most popular system in Korea, and this friction tie was composed of high tenacity PET filament and LDPE(Low Density Polyethylene) sheath. Due to the lack of direct-test results, design coefficients of friction tie (creep reduction factor) had been determined by quoting the previous and the foreign reference data. This is an unreasonable fact for the use of friction ties. In this study, the creep tests were performed to evaluate the creep behavior of friction tie, and the reduction factor of creep was calculated for the correct design of geosynthetic reinforced earth retaining walls. From the test results, finally it was found that the allowable creep strength of friction tie is 60% of Tult during service life, and creep reduction factor is 1.67 for each grade of friction ties.

Evaluation of Reliability of Strain Gauge Measurements for Geosynthetics (토목섬유 보강재에 적용한 스트레인게이지 실측값의 신뢰성 평가)

  • Cho, Sam-Deok;Lee, Kwang-Wu;Li, Zhuang;Kim, Uk-Gie
    • Journal of the Korean Geosynthetics Society
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    • v.14 no.4
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    • pp.87-96
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    • 2015
  • Geosynthetics are widely used in different ways such as reinforcement of structures in road, railway, harbor and dam engineering, drainage, separation and erosion prevention. They are especially applied to reinforced retaining wall and slope or ground reinforcement. Recently, geosynthetics reinforced pile supported (GRPS) embankment was developed to improve stability and construability of embankments in railway engineering. Extension strains are usually measured by strain gauges adhered to geosynthetics to evaluate the stability of geosynthetics. However, the measurements are influenced by manufacturing method and stiffness of geosynthetics and also adherence of strain gauge. In this study, wide-width tensile strength tests were performed on three types of geosynthetics including geogrid, woven geotextile and non-woven geotextile. During the test, strains of geosynthetics were measured by both video extensometer and strain gauges adhered to the geosynthetics and the measured results were compared. Results show that the measured results by strain gauges have high reliability in case of large stiffness geosythetics like geogrid and woven geotextile, whereas they have very low reliability for small stiffness geosythetics like non-woven geotextile.

Tensile Strength-Strain Relationship of Various Geogrids (다양한 지오그리드의 인장강도-인장변형 관계 특성)

  • Han, Sang-Hyun;Yea, Geu-Guwen;Lee, Kwang-Wu
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.2
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    • pp.83-93
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    • 2012
  • Since reinforced soil walls were introduced in domestic civil engineering society in early 1980's, various reinforcing materials including metal strips, bar mats, and sheet-type reinforcement using geotextile, geogrid, and etc. have been developed for construction purpose. Especially, the geogrid has been mostly used as a reinforcement for reinforced earth structures. This paper describes the tensile behaviors of four types of domestic geogrids. Also, a series of the wide-width tensile tests on three types of geogrids were conducted to assess the reliability of the tensile strains in geogrid measured by strain gauge. The tensile strain by strain gauge is larger than real strain of the geogrid and a difference between strain gauge reading and real strain non-linearly increase with increasing the tensile strain. However, when the tensile strain is smaller than 3%, a difference between strain gauge reading and real strain is negligible.

Behavior of Geosynthetic Reinforced Wall with Heat Induce Drainage Method During Rainfall (열유도 토목섬유 배수공법이 적용된 보강토 옹벽의 강우시 거동 특성)

  • Shin, Seung-min;Sin, Chun-won;Yoo, Chung-Sik
    • Journal of the Korean Geosynthetics Society
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    • v.15 no.1
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    • pp.11-19
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    • 2016
  • This paper presents the results of a scale model test to the effect of heat exchanger drainage method in retaining wall of weathered granite soil. Purpose to rise in the temperature of the heat wires inside the weathered granite soil is preventing the collapse of the retaining wall and drainage smoothly moved to the drainage layer. Especially using a spray gun to simulate the rainfall since the rainfall drainage work is important for the rainfall effect on soil, find the difference about displacement of the retaining wall, change of volume water content, drainage, earth pressure and change in the strain of the geosynthetic was effected to heat exchanger within the soil. The result from applying the heat exchanger method decreased the earth pressure and displacement of the wall and increased drainage of water.