• Title/Summary/Keyword: Geogrid-reinforced

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Displacement and Earth Pressure Distribution of the Reinforced Soil Segmental Retaining Walls under the Simulated Cyclic Train Loading (모사열차 반복하중 재하에 따른 블록식 보강토 옹벽의 변위 및 토압 분포)

  • 이진욱;고태훈;이성혁;심재훈
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.620-625
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    • 2002
  • In this study, the simulated cyclic train loading test was carried out in order to investigate the dynamic behavior in/at the block type reinforced earth retaining wall. The results in this test were compared with unreinforced and reinforced case, respectively. It was shown that we confirmed the correlation between earth pressure and displacement, the confining effect of wall displacement by the effect of geogrid.

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Behavior Characteristics of Reinforced Earth Wall using Fiber-Mixed Soil Backfill (뒤채움재료로 단섬유혼합토를 사용한 보강토옹벽의 거동특성)

  • Cho, Sam-Deok;Ahn, Tae-Bong;Oh, Se-Yong;Lee, Kwang-Wu
    • Journal of the Korean Geosynthetics Society
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    • v.3 no.1
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    • pp.43-52
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    • 2004
  • Laboratory model tests were conducted to assess the behavior characteristics of geogrid reinforced earth walls using fiber-mixed soil backfill with different surcharge loads and reinforcement spacing. The models were built in the box having dimensions, 100cm tall, 140cm long, and 100cm wide. The reinforcements used were geonet(tensile strength, 0.79t/m) and geogrid(tensile strength, 2.26t/m). Decomposed granite soil(ML) with or without polypropylene fiber was used backfill material. Strain gauges and LVDTs were installed on the retaining walls to measure the strain of the reinforcements and the displacements of the wall facings.

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Short - and Long-term Load Carrying Capacity of Geogrid Reinforced Stone Column - A numerical investigation (지오그리드 보강 Stone Column의 장.단기 하중 지지 특성 - 유한요소해석을 통한 고찰)

  • Lee, Dae-Young;Kim, Sun-Bin;Song, Ah-Ran;Yoo, Chung-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.434-444
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    • 2006
  • The stone column method is widely used in Europe as an alternative to conventional pile foundations. Several benefits of using the stone column method include sound performance, low cost, expediency of construction, and liquiefaction resistance, among others. Recently, geosynthetic-encased stone column approach has been developed to improve its' load carrying capacity through increasing confinement effect. Although such a concept has successfully applied in practice, fundamentals of the method have not been fully explored. This Paper Presents the results of an investigation on the loading carriying capacity of geogrid-encased stone column using a series of 2D finite element analyses. The results of the analyses indicated improved short- and long-term carrying capacity of the geogrid-encased stone column method over the conventional strone column method with no encasing.

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An Experimental Study on the Combined Effect of Installation Damage and Creep of Geogrids (지오그리드의 시공시 손상 및 크리프 복합효과에 대한 실험적 연구)

  • Cho, Sam-Deok;Lee, Kwang-Wu;Oh, Se-Yong;Lee, Do-Hee
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.561-568
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    • 2005
  • The factors affecting the long-term design strength of geogrid can be classified into factors on creep deformation, installation damage, temperature, chemical degradation and biological degradation. Especially, creep deformation and installation damage are considered as main factors to determine the long-term design strength of geogrid. Current practice in the design of reinforced soil is to calculate the long-term design strength of a reinforcement damaged during installation by multiplying the two partial safety factors, $RF_{ID} and RF_{CR}$. This method assumes that there is no synergy effect between installation damage and creep deformation of geogrids. Therefore, this paper describes the results of a series of experimental study, which are carried out to assess the combined effect of installation damage and creep deformation for the long-term design strength of geogrid reinforcement. The results of this study show that the tensile strength reduction factors, RF, considering combined effect between installation damage and creep deformation is less than that calculated by the current design method.

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Time-Dependent Deformation Characteristics of Geosynthetic-Reinforced Soil Using Plane Strain Compression Tests (평면변형압축시험을 이용한 보강토의 시간 의존적 변형 특성 연구)

  • Yoo Chung-Sik;Kim Sun-Bin;Lee Bong-Won
    • Journal of the Korean Geotechnical Society
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    • v.21 no.10
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    • pp.85-97
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    • 2005
  • Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exist concerns over long-term residual deformation when subjected to repeated and/or cyclic loads, especially when used as part of permanent structures. In view of these concerns, in this paper time-dependent deformation characteristics of geosynthetic reinforced soil under sustained and/or repeated loads were investigated using a series of plane strain compression tests on geogrid reinforced weathered granite soil specimens. The results indicate that sustained or repeated loads can yield appreciable magnitudes of residual deformations, and that the residual deformations are influenced not only by the loading characteristics but by the mechanical properties of geogrid. It is also found that the preloading technique can be effectively used in controlling residual deformations of reinforced soils subjected to sustained and/or repeated loads.

Measured Behavior of Full-Scale Soil-Reinforced Segmental Retaining Wall (계단식 형태의 블록식 보강토 옹벽의 거동특성)

  • Yoo, Chung-Sik;Jung, Hyuk-Sang
    • Journal of the Korean Geosynthetics Society
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    • v.2 no.1
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    • pp.15-25
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    • 2003
  • This paper presents the results of instrumentation of a two-level of soil-reinforced segmental retaining wall. Instrumentation items include the lateral wall displacements and the geogrid strains at several locations. The instrumentation is still long carried in order to examine long-term behavior. The result indicate that the upper wall has a significant effect on the behavior of the lower wall doubling the wall moved. The wall also exhibits significant post-construction movements that had ceased several months after the wall completed. The implication of the findings from this study was discussed in great detail.

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Site Monitoring of the Retaining Wall Reinforced by Geogrids with Block Type Facings (지오그리드 보강토 옹벽의 계측평가)

  • Kim, Jin-Man;Lee, Dae-Young;Ma, Sang-Joon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.1
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    • pp.106-114
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    • 2006
  • Uses of geosynthetics as a reinforcing material for earth structures have ever increased due to their excellent economy. fine external appearance. and easy construction. In the current practice of geosynthetics. however, the lacks of the standardized method of evaluating the soil/geosynthetics friction properties and the inconsistency of conventional design methods develop confusion to the civil engineers. The purpose of site monitoring of the retaining wall reinforced by geogrids was to evaluate the applicability of existing design methods to, and performance of. CHAMSTONE wall system. Full scale field performance during and after construction was monitored by incorporating instrumentation including strain gauges on the geogrid and soil pressure cells. The difference of the reinforcing effects of geosynthetics embedded in the soil will be also investigated by comparing of the line and curve types of retaining wall reinforced by geogrids with block type facings.

Pullout Characteristics of Waste Fishing Net Reinforced Bottom Ash using Pullout Test (인발시험에 의한 저회에 보강된 폐어망의 인발특성 연구)

  • Kwon, Soon-Jang;Kim, Yun-Tae
    • Journal of the Korean Geosynthetics Society
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    • v.12 no.4
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    • pp.57-66
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    • 2013
  • In this study, pullout tests were carried out to evaluate pullout characteristics of waste fishing net (WFN), which added into bottom ash for recycling both bottom ash and WFN. Three different mesh size of WFN (WFN20:$20mm{\times}20mm$, WFN30:$30mm{\times}30mm$, WFN40:$40mm{\times}40mm$) and geogrid were added as a reinforcement. Pullout characteristics of waste fishing net were compared with those of the geogrid. Pullout test results showed that pullout strength and stiffness of WFN20 are a little less than those of geogrid. However, the pullout friction angle of WFN20 is similar to that of geogrid due to bearing resistance induced from transverse rib because thickness of WFN20 is greater than geogrid. Pullout test results also indicated that distribution of residual strain along reinforcement after test depends on overburden stress. Residual strain at the tip of reinforcement increased with an increase in overburden stress due to concentration of pullout force on the tip of reinforcement.

Experimental Study on the Reinforcement Effect of Geogrid in Soft Ground Improvement (연약지반 개량시 지오그리드 보강효과에 관한 실험적 연구)

  • Ham, Hyeon-Su;Lee, Sang Duk
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.2
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    • pp.1-7
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    • 2018
  • The number of construction of roads and railroads in soft ground such as coastal areas and wetlands is getting increased. For this reason cases that soft ground improvement is applied are increasing. In general, many ground improvement methods consider only the working conditions at the time or only economy. But if the working condition and economy are taken into consideration together, the number of applicable construction method gets limited. In such a case, a ground improvement method using both the surface layer portion and the deep layer portion is applied. But the basic research on this is still insufficient in practice. Therefore, in this study the reinforcement effect of geogrid was investigated by carrying out the model test realizing the case in which soft surface ground improvement and depth improvement are simultaneously applied. And it was intened to understand the effect of the thickness of surface layer, the diameter and length of the improvement body on the reinforcement effect of geogrid. The result showed that the effect of the surface layer thickness is greater than the effect of the deep layer diameter. Moreover, when the surface layer is reinforced with a geogrid, the strength of the surface layer part is enhanced and this effect of a geogrid reinforcement caused the reduction of surface settlement.

A Study on the Evaluation of Field Installation Damage and Strength Reduction Factor of Geogrid for Reinforced Retaining Wall (보강토 옹벽용 지오그리드의 현장 내시공성 및 강도 감소계수 평가에 관한 연구)

  • Park, Juhwan;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.7
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    • pp.5-12
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    • 2012
  • Recently the installation of reinforced earth retaining walls in the domestic construction site has increased, surpassing conventional RC walls. These reinforced walls have various types depending on the reinforcing material, installation method and the form of face panel. However, there are difficulties in design and construction management due to the unproved safety of construction method. In case of reinforcing materials, despite the fact that they come in all different sizes and types produced by small businesses or partially imported with cheap price and low quality, no proper standards for designing the walls have been suggested. In order to apply reinforced retaining wall system to broad cases and design the walls effectively considering site conditions, specific design and construction guidelines for efficient construction management are needed. In conclusion, this study verified that reduction factors can be greatly affected by grain sizes and stiffness of backfill materials and granularity range, therefore in case of relatively large construction site, it is required to redesign the reinforced retaining wall by evaluating site installation resistance test, applying respective reduction factors to each backfill material and select the right geogrid depending on the usage of retaining wall so as to enhance the safety of reinforced earth retaining walls with efficiency.