• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6C
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• pp.249-257
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• 2012

The reinforced earth method is financially viable. Furthermore, it overcomes environmental limitations and is therefore employed in retaining walls, slopes, foundations, roads, embankments, and other structures. However, in some cases, reinforced retaining walls are not strong enough in the curved sections and can collapse. Such mishaps are believed to occur because of an unsatisfactory analysis of the curved sections of a reinforced retaining wall. Accordingly, with the aim of investigating the workability and structural safety of curved sections of various types, this study investigates the differences in the estimated horizontal displacements of curved sections of various types and subsequently uses this information to study and analyze preliminary data so that appropriate measures can be taken to resolve alignment issues. The results of an experiment reveal that when a load is applied to curved sections of both concave and convex types, the largest horizontal displacement occurs at the center of the section. In the concave form, the earth pressure force is directed inward, whereas in the convex form, this force is directed outward. As a result, the horizontal displacement in convex forms is larger than that in concave forms. Convex reinforced earth structures are subjected to earth pressures as well as lateral earth pressure, therefore horizontal displacements in convex curved sections is larger than that of concave curved sections.

• Journal of the Korean GEO-environmental Society
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• v.17 no.12
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• pp.27-34
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• 2016

Many steepened slopes have become increasingly advantageous because of the desire to increase land usage and decrease site development costs. The proven concept of tensile reinforcement allows construction of slopes with far steeper face angles than the soils natural angle. Steepened slope face reinforced with improved soil can increase land usage substantially while providing a natural appearance. The paper presents composite reinforced earth with improved soil surface and geogrid-reinforced backfill. For the stability of the steepened slope, the behavior of the composite reinforced earth are validated and verified by case study and numerical analysis. The case study has performed to investigate the deformation of reinforce soil slope for 14 months. Its horizontal behavior by general vertical load shows within the safe range (0.5% of structure height). As a result of numerical analysis and case study, the reinforcement effect of the steepened slope technique using improved soil is sufficient to be constructed as reinforced soil slope.

• 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.

• Journal of the Korean Geosynthetics Society
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• v.4 no.2
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• pp.29-38
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• 2005

It is essential to take consideration of long-term deformation characteristics of mechanically stabilized earth wall user sustained and repeated loads for design and construction, especially for use as part of permanent structures. This paper presents the long-term performance of a full-scale geogrid reinforced segmental retaining wall results based on the measured strains in geogrids for three years. The results indicate that the reinforcement tensile strains tend to continuously increase after wall completion with the increase being more pronounced in the reinforcement layers in the lower tier. It can be concluded that the long-term deformation should be taken in account for walls constructed as part of permanent structures for which wall deformation should be controlled.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.45-53
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• 2011

Recently reinforced retaining walls secure their position as a stabilized method of construction replacing concrete retaining walls gradually. However, in the event of using extensible reinforcement, a bulging phenomenon can be happened in the front of reinforced retaining walls. Bulging of reinforced retaining walls means a phenomenon that, in the height of an arbitrary block, the upper part and the lower part of the block don't secure a relative position in design. Therefore, it is judged that it has the necessity to be examined in design since reinforcement needs metamorphosis to some degree to display tensile force. Therefore, the study examined about how extensibility of reinforcement had an effect on movement of reinforced retaining walls through a small-scale model test with aluminum rods. The study used Changhoji(traditional korean paper made from mulberry bark) as inextensible reinforcement and membrane as extensible reinforcement. As the result of the test, rigidity of reinforcement had a lot of effects on displacement of reinforced retaining walls and generally occurrence point of the maximum horizontal displacement had a tendency transferring to the upper part of walls according to rigidity of reinforcement was increased.

• Geotechnical Engineering
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• v.8 no.4
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• pp.5-16
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• 1992

The main purpose of this the sutdy is to develop the reinforced earth structure design method considering induced stresses and deflections resulting from placement and compaction of soil. In this paper, the new reinforcement Geolog developed by the author is also introduced which is being used as one of the effective earth reinforcing structure against compaction induced stresses. This study adopted the Seed's bilinear model in the estimation of the com paction induced stresses and compute the peak lateral stresses during compaction by doubled Boussinessq's elastic solution of mirror image theory, thereafter, calculate the residual compaction induced lateral stresses from the above peak lateral stress by the residual fraction. It is considered to be reasonable that the compaction induced stresses be added to the lateral earth pressures estimated from conventional gravity analysis considering the actual stresses during service life of the structures. "GEOLOG", a composite of steel bar and attached concrete stopper is found to be effective against tension and pull - out failure. In this paper, the design method considering the compaction induced stresses and the effect of Geolog reinforcement is suggested for the remforced earth structures where backkfill settlement on displacements are not allowed as in the cases of the bridge abutments or double faced reinforcement earth structures.tructures.

• Journal of the Korean Geosynthetics Society
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• v.5 no.4
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• pp.35-42
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• 2006

This paper describes a field experience on geogrid-reinforced soil walls rising up to 29.5m in height. Since experiences of design and construction on very high-raised geogrid reinforced soil wall were limited, thorough design and construction management was performed for safe construction of the wall. Regarding design of the wall, both internal and external stabilities were examined based on the design guideline specified by FHWA and overall slope stability analyses were performed by using Bishop simplified method. Moreover, a series of instrumentations were performed. The results of instrumentation for two tiered reinforced soil wall showed that not only the deformations of both the wall face and the reinforcement but also the horizontal earth pressures acting on the wall facing were very small. These results indicate that the reinforced soil wall technology can be applied successfully for high-raised tiered wall more than 20m heights and FHWA design guideline is very conservative for that large wall.

• Geotechnical Engineering
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• v.12 no.1
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• pp.63-72
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• 1996

The current practice in construction of reinforced earth retaining walls is to use a granular soil for the backfill material. When the material is available in site, the construetion cost can be remarkably reduced. As the weathered granite soils are abundant and widely distributed throughout the Korean peninsula: whether they are suitable or not as the backfill material is considered to be the most important key in economic construction of the wall. This paper investigates the grain size distribution of the weathered soils which locate at many places throughout the nation and then examines limitation of their use based on the specifications of different countries. The variaton of shear strength with both different fine contents and saturation is also investigated. It is known that the grain size distribution of most weathered soils are not satisfied with the general requirement. However their use is possible in wide range when the backfill keeps in unsaturated condition using good drainage facilities and 1 or pervious reinforcements.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.83-90
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• 2004

Retaining walls with reinforced earth have been constructed around the world. The use of reinforced earth is a recent development in the design and construction of earth-retaining structure. It is believed that reinforced retaining wall has some advantages which make construction quite simple basically. It wilt take short construction time relatively, comparing, fur example with reinforced-concrete retaining wall. In addition, low price and easy construction will be good attractive points in practical point of view. In this study, five field-tests monitoring data for lateral pressures on geogrid-reinforced retaining wall have been compiled and evaluated. Based on field-tests it is found that horizontal displacements of the facing was measured to be about 0.19∼0.76% and that the maximum tensile strains of reinforcement was evaluated to be about 0.66∼1.98%. The maximum tensile strains, measured from each site, do not reach 5% of the practical allowable strain of the geogrid. And also it is found that the lateral pressure distributions of reinforced-earth retaining wall are close to a trapezoid shape like a flexible retaining wall system, instead of a theoretical triangular shape.

• Journal of the Korean Geosynthetics Society
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• v.4 no.3
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• pp.21-33
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• 2005

This paper presented a mechanism of the soil structure reinforced by geosynthetics, in which the reinforcing mechanism is treated as the effect arising from the reinforcement process to prevent the dilative deformation of soil under shearing. A full-scale in-situ model test was carried out by introducing the prestress method to enhance the geosynthetic-reinforcement, and the prestress effect through the FEM is also examined. The elasto-plastic model and the initial parameters needed in the FEM are presented. Moreover, the theoretical prediction is compared with the experimental results, which were obtained by a full-scale in-situ model test.