• Title/Summary/Keyword: Reinforced earth

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Analysis on Failure Causes and Stability of Reinforced Earth Wall Based on a Field Case (현장사례를 이용한 보강토옹벽의 파괴원인 및 안정성 분석)

  • Hong, Kikwon;Han, Jung-Geun;Lee, Jong-Young;Park, Jai-Seok
    • Journal of the Korean Geosynthetics Society
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    • v.12 no.1
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    • pp.109-114
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    • 2013
  • This paper describes the global stability of the reinforced earth wall, which was collapsed by heavy rainfall. The seepage analysis was conducted to confirm the change effect of groundwater level on slope with reinforced earth wall. The seepage analysis result confirmed that the change of groundwater level is greatly influenced by rainfall. According to the change of groundwater level, the global stability analysis with reinforced earth wall was conducted based on the results of seepage analysis. The safety factor of the slope was 0.476 when the wall is collapsed firstly. The collapse cause analyzed that soil strength was weaken because the ground was saturated by continuous rainfall. Therefore, the global stability, which is considered heavy rainfall, should be conducted at design and construction of reinforced earth wall.

A case study on reinforcement and design application of reinforced earth wall using micro pile (마이크로 파일을 이용한 블록식 보강토옹벽의 보강 및 설계적용 사례 연구)

  • Hong, Kikwon;Han, Jung-Geun;Lee, Kwang-Wu;Park, Jong-Beom
    • Journal of the Korean Geosynthetics Society
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    • v.13 no.4
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    • pp.161-167
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    • 2014
  • This paper describes reinforcement method of reinforced earth wall near the abutment. The excessive displacement of a case affected by reduction of bearing capacity due to macro-environment condition like a coast. That is, the front displacement of reinforced earth wall has been happening continuously due to strength reduction of foundation ground. The micro pile is applied to reinforcement method, in order to secure a bearing capacity and global slope stability of reinforced earth wall. The results of numerical analysis confirmed that reinforcement method based on micro pile can secure a stability of structure, while the reconstruction of reinforced earth wall is impossible by construction and macro-environment condition.

Numerical Analysis for Optimum Reinforcement Length Ratio of Reinforced Earth Retaining Wall (보강토옹벽의 최적 보강길이비 산정을 위한 수치해석적 연구)

  • Park, Choonsik;Ahn, Woojong
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.12
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    • pp.5-14
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    • 2018
  • Recently, method of reinforced earth retaining wall have been proposed according to the material of facing, geosynthetic, construction method, and facing slope. However, the regulations such as the design method and detailed review items according to each construction method are not clear, and collapse due to heavy rainfall frequently occurs. In this study, to obtain a more stable technical approach in the design of reinforced earth retaining wall, the combination of the pullout failure of reinforced earth retaining wall and the optimal reinforcement ratio of height using reinforced earth retaining wall using a single strength reinforcement is assumed, optimum design of stiffener, optimal design of superimposed wall and optimum length ratio of reinforcement material of geosynthetics are proposed through safety factor according to reinforcement length ratio (L/H).

Effect of preloading on residual deformation of Back-To-Back reinfored wall (선행하중작용시 Back-To-Back(BTB) 보강토 옹벽의 거동 특성)

  • Kim, Sun-Bin;Yoo, Chung-Sik;Kim, Jae-Wang;Joo, Sung-Yong
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.251-258
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    • 2008
  • The use of reinforced earth walls in permanent structures is getting it's popularity. Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exit concerns over long-term residual deformation when subjected to repeated and/or cyclic loads, during their service period. In this investigation, the effect of preloading in reducing long term residiual deformation of back-to-back reinforced soil wall under sustained and/or repeated loading enviormentment using a series of reduced-scale model tests. It is found that the preloading technique can be an effective means of controlling residual deformations of reinforced soils under varisous loading conditions.

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A Study on Cause Analysis and Countermeasures of Chloride Attack of Reinforced Earth Retaining Walls Installed on Bridge Abutment (염해로 인한 교대부 보강토옹벽 손상 원인 분석 연구)

  • Do, Jong-Nam;Kim, Nag-Young;Cho, Nam-Hun;You, Kwang-Ho
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.12
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    • pp.59-64
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    • 2018
  • The damages to the reinforced earth retaining wall are divided into the front wall, foundation, drainage and upper slope. Damage of reinforced earth retaining wall is mainly caused by damage caused by drainage problem in the field. Recently, damage caused by snow removal materials have been occurred. Recently, the amount of snow removal materials used in winter is increasing due to abnormal weather. This chlorides degrades the concrete structure, where the reinforced earth retaining wall was no exception. There has recently been a case in which the front wall of the reinforced earth retaining wall deteriorates due to the chlorides introduced into the back filling portion through the drainage passage. Therefore, in this study, the cause of damages of reinforced earth retaining wall constructed in bridge abutment was analyzed, and an analytical study was conducted on the countermeasure. As a result, it was found that chlorides, which was introduced through the drainage system in the expansion joint of the bridge shift part or the upper structure, is infiltrated into the back part of the reinforced earth retaining wall and damaged. Therefore, it is suggested to improve the drainage system and restored the stiffness of the front wall.

A Study on the Application of Soil-Reinforced Retaining Wall for Excavation Slope (절토사면에서 보강토 옹벽의 적용성 연구)

  • Byun, Yoseph;Wrryu, Woongryeal;Lee, Dongho;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.2
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    • pp.53-60
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    • 2010
  • Considering environmental issues and lack of space, it is a necessity to minimize the amount of excavation. Various types of excavation methods are being used in practice. This study proposes a reasonable method for estimating the earth pressure acting on a reinforced wall in front of a excavated slope. The measured data in the field and numerical analyses were used. Results of the study shows that the earth pressure acting on the excavated wall is less than that estimated by Rankine's equations. It was shown that when the excavated slope is used with the reinforced wall, the pressures acting on the reinforced wall can be greatly reduced.

Analysis of Damage Cases of Reinforced Earth Retaining Walls for Expressways at the Time of Introduction 30 Years (도입 30년 시점에서 고속도로 보강토옹벽의 손상사례 분석)

  • Do, Jongnam;Kim, Nagyoung;Kim, Myoungil;Park, Doohee
    • Journal of the Korean GEO-environmental Society
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    • v.21 no.12
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    • pp.29-34
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    • 2020
  • Reinforced earth retaining walls were developed in France in the 1970s and began to be applied in earnest to Korea in the 1990s. And now, about 1,300 reinforced soil retaining walls support the embankment of highways and bridge connections. The reinforced earth retaining wall construction technology has evolved day by day, and in recent years the reinforced earth retaining wall itself has been developed and introduced as a demonstration. However, various damages are constantly occurring in the reinforced earth retaining walls constructed throughout the highway. The cause of this was analyzed as minor defects in the design, construction, and maintenance stages. The solution for this is a change in perception of the importance of each individual process, but this does not form overnight. In this study, 30 years have passed since the introduction of the reinforced soil retaining wall on the highway, the damage cases were analyzed and categorized that have occurred in the reinforced soil retaining wall so far, and attempted to present a confrontation. As a result, the damage occurring on the reinforced soil retaining wall was divided into 10 types, and the causes and countermeasures in the design, construction, and maintenance stages for each were derived.

Evaluation on Stability of Reinforced Earth Wall using Geosynthetic Strip with Rounded Band Anchor (띠형 섬유보강재가 적용된 블록식 보강토옹벽의 안정성 평가)

  • Lee, Kwang-Wu;Cho, Sam-Deok;Han, Jung-Geun;Hong, Ki-Kwon
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.3
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    • pp.43-51
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    • 2012
  • This paper describes the stability evaluation of reinforced earth wall using geosynthetic strip based on field test. The wall facing, which is applied in field, is able to present excellent scenery, and the reinforcement has improvement effect of pullout resistance based on rounded band anchor. The measurement is conducted according to construction elapsed time of structure for earth pressure, horizontal displacement of wall facing and reinforcement strain in field test. The evaluation results show that the measured earth pressure is less than theoretical earth pressure due to dispersion effect of earth pressure by geosynthetic strip. The horizontal displacement of wall facing is also satisfied a empirical criteria. The measured strain of reinforcement had nearly no effect on stability of the reinforced earth wall. Therefore, the geosynthetic strip with rounded band anchor can be applied in the reinforced earth wall, and the reinforced earth wall with geosynthetic strip can be commonly used in field because it has a structural stability.

A Case Study on the Hybrid Reinforcement Retaining Wall System Reinforced by Soil Nail and Steel Strip (쏘일네일과 강재스트립으로 보강된 복합보강토옹벽 시스템의 사례연구)

  • Chun, Byung-Sik;Kim, Hong-Taek;Cho, Hyun-Soo;Do, Jong-Nam
    • Journal of the Korean Geotechnical Society
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    • v.24 no.12
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    • pp.5-12
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    • 2008
  • The reinforced earth wall, which is able to improve the strength of soil highly, is required in case of supporting high surcharge load such as high speed rail way, high embankment road, and massive reinforced earth wall in a mountainous area. And also, it is continuously required that the method is able to minimize the amount of excavated soil on account of environmental issue, boundary of land, etc., on excavation site. However, because the required length of reinforcement should be $60{\sim}80%$ of the height of reinforced earth wall for general reinforced earth wall, in fact the reinforced earth wall is hardly applied on the site of cut slope. In this paper we studied the design and construction cases of hybrid reinforcement retaining wall system combined with steel strips and soil nails, connecting the reinforced earth wall reinforcements to the slope stability reinforcements (soil nails) to ensure sufficient resistance by means of reducing the length of reinforcements of reinforced earth wall. And the feasibility of hybrid reinforcement retaining wall system, suggested by real data measured on site, is also discussed.