• International Journal of Railway
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• v.6 no.3
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• pp.107-111
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• 2013

In order to constrain the railway roadbed settlement which causes track irregularity, and thus threats running stability and ride quality, advanced Back-to-Back (BTB) reinforced retaining wall was numerically analyzed as railway roadbed structure. This study is intended to improve conventional Back-to-Back reinforced retaining wall as the technology which would reduce the roadbed settlement in a way of constraining the lateral displacement of its prestressed vertical facing and inducing arching effects in roadbed (backfill) placed between masonry diaphragm wall and vertical facing. As a result of numerical analysis, it was found that the roadbed settlement was reduced by 10% due to the prestressed vertical facing and embedded masonry diaphragm wall of the advanced Back-to-Back reinforced retaining wall system.

• Journal of the Korean Geotechnical Society
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• v.25 no.12
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• pp.131-142
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• 2009

Geosynthetic reinforced soil walls are well recognized alternatives to conventional retaining walls due to many advantages in terms of ease of construction, economy, and aesthetics, among others. In recent years, the use of back-to-back (BTB) geosynthetic reinforced soil walls has been increasing for roadway and railway construction. However, there are insufficient studies concerning the behavior of BTB type geosynthetic reinforced soil walls. In this study a series of finite element analysis were performed for BTB walls with various wall geometry and reinforcement distribution. The results were then analyzed to relate the wall geometry and reinforcement distribution and the performance of BTB walls. Optimum reinforcement pattern was also investigated.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.41-52
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• 2008

This paper concerns the load carrying capacity of back-to-back reinforced soil wall for use in roadway and railway construction. Two test conditions, designed with due consideration of the FHW A design guideline, were first developed and a number of cases having different reinforcement lengths were tested under a surchage loading until failure. The results indicated that for cases in which two sides of reinforcements do not overlap, the wall behavior was similar to those of single wall. For cases in which the reinforcements overlap each other, on the other hand, the load carrying capacity of the wall significantly decreased when reinforced with reinforcement layers having lengths less than 50% of the wall height.

• 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.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.55-66
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• 2011

This paper presents the results of an investigation on the failure mechanism of geosynthetic reinforced soil walls in back-to-back configuration using 1-g reduced-scale model tests as well as discrete element method-based numerical investigation. In the 1-g reduced scale model tests, 1/10 scale back-to-back walls were constructed so that the wall can be brought to failure by its own weight and the effect of reinforcement length on the failure mechanism was investigated. In addition, a validated discrete element method-based numerical model was used to further investigate the failure mechanism of back-to-back walls with different boundary conditions. The results were then compared with the failure mechanisms defined in the FHWA design guideline.

• Journal of the Korean Geotechnical Society
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• v.24 no.6
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• pp.101-116
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• 2008

The use of reinforced earth walls id permanent structures is getting its popularity. Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exists concerns over long-term residual deformations when subjected to repeated and/or cyclic loads, during their service period. In this investigation, the effects of pre-loading in reducing long term residual deformation of reinforced soil structures under sustained and/or repeated loading environment are investigated using a series of reduced-scale model tests. A model pier and a back-to-back (BTB) reinforced soil structures were constructed and tested under various loading and backfilling conditions. The results indicate that the pre-loading technique can be an effective means of controlling residual deformations of reinforced soils under various loading conditions.

• Geotechnical Engineering
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• v.2 no.3
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• pp.51-66
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• 1986

The design of fabric reinforced retaining wall structure was discussed in this article. It was confirmed that the reinforced retaining earth wall which was designed by new theoretical formulae developed this time was stable structurally and economically. The plastic fabric filter which was placed in layers behind the facing element reduced the lateral earth pressure on the wall elements in comparison with a conventional retaining earth walls. The reinforcing characteristics of earth wall was governed by the spacing of fabric layers, effective length of fabrics, particle distribution and compaction, and thus it is essential that, in the construction field, the reinforcing strips should be selected in order to develop the maximum friction forces bet.eon soil and fabric filters. The maximum tensile stress developed from the reinforcing strips was appeared at a little far distance from the back of skin element and it was not well agreed with the Rankine's theory but distributed well as a symmetrical shape against the point of the maximum tensile stress. The total length of the different layers should be sufficient so that the tension in the fabric strip could be transferred to the backfill material. Also the total stability of reinforced earth wall should be checked with respect to a failure surface which extended blond the different lathers.

• 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.

• Journal of the Korean Geotechnical Society
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• v.24 no.5
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• pp.99-106
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• 2008

This study is concernsed with the effect of a chimney drainage system installed at the back of reinforced soil block on preventing the pore water pressure development. A series of finite-element analyses based on transient seepage analysis were performed for a number of cases with different patterns of the chimney drainage system. The results were thoroughly analyzed to get insight into the mechanism of pore water pressure reduction effect of the chimney drainage system. It is shown that a vertical drainage system installed at the back of reinforced zone can be an effective means of maintaining the wall stability during rainfall by preventing pore pressure increase in the reinforced as well as the backfill zones. Also shown is that the optimum height of the chimney drain is 50% of the wall height. Practical implications of the findings were discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.06a
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• pp.1-11
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• 2001

This Paper presents the result of a parametric study on the behavior of stiffened grid reinforced segmental wall resting on non-yielding foundation. The parametric study was conducted using the nonlinear finite element analysis. In the finite element analysis, the step by step construction of the wall such as backfill, block reinforcement, block/backfill and soil/reinforcement interfaces were carefully modeled. The mechanical behavior of stiffened grid reinforced segmental walls was then investigated based on the result of analysis with emphasis on the effect of reinforcement stiffness on the behavior of the wall. The results of analysis indicate that the horizontal wall displacement decrease; with increasing the reinforcement stiffness at a decreasing rate, and that the horizontal stress at the back of the reinforced soil block does not much vary with the reinforcement stiffness. It is also revealed that the calculated maximum vertical stress at the base of the reinforced soil block agrees well with that based on the Meyerhof distribution and that the reinforcement and the connection force are considerably smaller than what might be expected based on the current design assumptions. The implications of the findings from this study to current design approaches were discussed in detail.