• The Journal of Engineering Geology
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• v.17 no.4
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• pp.601-613
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• 2007

It is reported that factors affecting the behavior of reinforced earth retaining walls built on soft ground are not only basic physical properties but also the increase of load by the reinforced earth retaining walls, consolidation period, pore water pressure, etc. This study analyzed the behavior of reinforced earth retaining walls and soft ground using SAGE CRISP, a ground analysis program. First, we examined the effect of the replacement method, which was to prevent the excessive displacement of reinforced earth retaining walls, in improving the behavior of the walls. Second, we compared and analyzed how the behavior of ground is affected by the vertical interval of stiffeners on the back of reinforced earth retaining walls after the application of the replacement method. Lastly, we proposed the optimal replacement width and depth in the application of the replacement method. The results of this study proved that the replacement method is considerably effective in improving the behavior of reinforced earth retaining walls. In addition, the vertical interval of stiffeners on the back of reinforced earth retaining walls appeared effective in improving the horizontal displacement of the top of retaining walls but not much effective in improving the vertical displacement of the back of retaining walls. In addition, improvement in horizontal-vertical displacement resulting from the increase in replacement width was not significant and this suggests that the increase of replacement width is not necessary. With regard to an adequate replacement depth, we proposed the ratio of replacement depth to the height of retaining walls(D/H) according to the ratio of the thickness of the soft layer to the height of retaining walls(H/T).

• Journal of the Korean Geosynthetics Society
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• v.3 no.1
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• pp.3-15
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• 2004

Geogrid reinforced soil structures with segmental block facing have been increased since 1990's, because of the convenience of installation and the flexible appearance. In this paper, the behavior of the segmental reinforced retaining wall was analysed with the results of field monitoring. The height and length of reinforced wall are 12m and 25m, respectively. The field measurement equipments are horizontal and vertical earth pressure cells, settlement plate, strain gauge, inclinometer, and displacement pin. Based on the field monitoring, the horizontal earth pressure was approximately 0.3times higher than that of the theoretical method and the maximum tensile strength of reinforcement was 26.2kN/m. The displacement of facing wall was 23mm at the point of 7.1m height of the wall and toward the wall facing. The results of the study indicate that the segmental reinforced retaining wall is in a stable condition because of good compaction & reinforcement effects, and long period of construction time. Finally, the computer program of SRWall is very useful tool to design the segmental reinforced retaining wall.

• Journal of the Korean Geotechnical Society
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• v.21 no.1
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• pp.51-58
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• 2005

The use of geogrid for SRW systems and bridge abutment has increased rapidly over the past 10 years in Korea. The concept of segmental retaining walls and reinforced soil is very old and for example The Ziggurats of Babylonia(i.e. Tower of Babel) were built some 2,500 to 3,000 years ago using soil reinforcing methods very similar to those described in current design. Modern SRW(Semental Retaining Wall) units were introduced in 1960's as concrete crib retaining wall systems. In this paper, the friction properties between segmental concrete units and geogrid are investigated by performing various tests.

• Journal of the Korean Geosynthetics Society
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• v.3 no.4
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• pp.13-19
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• 2004

This paper presents the results of an investigation on the failure mechanism of geosynthetic-reinforced segmental retaining walls in tiered arrangement using reduced-scale model tests. In this laboratory model tests, a reduced scale model of the full-scale geosynthetic-reinforced wall which was constructed in Geotechnical Experimental Site at Sungkyunkwan University was used to perform a study on the failure mechanism. In order to a high degree of realism, the geometry of the wall and the material properties were selected applying Similitude Laws was used to perform laboratory model tests. And contrary to the previous failure tests with various surcharge pressures, the failure by the tired wall weight was observed. Primary variables considered in the model tests include the different offset distance between the tiers and the different reinforcement length in the lower tier and as a result of the parametric study, a different failure pattern was observed.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.15-25
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• 2001

본 고에서는 블록식 보강토 옹벽의 지진시 거동에 관한 유한요소해석 결과를 다루었다. 보강토 옹벽의 지진시 변위거동을 검토한 결과 벽체저부를 지점으로 하는 캔틸레버형태의 변위 거동을 보였으며 따라서 옹벽 상단부에서의 보강재 인장력 증가가 현저하게 나타나 벽체전반에 걸친 분포양상은 균등한 경향을 보였다. 한편, 지진하중으로 인한 증분유발인장력에 관하여 검토한 결과 기존의 보강토 옹벽 내진설계기준과 비교하여 정성.정량적인 측면에서 상당한 차이를 보였으며 내진설계기준이 전반적으로 과소평가 하는 것으로 나타났다. 아울러서, 내진설계측면에서 변위억제 방안에 관한 매개변수 연구결과 임의 조건에 있어서 최대의 보강효과를 나타내는 보강재 임계 강성과 포설길이가 존재하며 최적의 보강효과를 얻기 위해서는 이에 대한 종합적인 검토가 요구되는 것으로 나타났다. 본 고에서는 연구결과를 종합적으로 고찰하여 실무 적용관점에서의 주안점을 언급하였다.

• Journal of the Korean Geosynthetics Society
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• v.2 no.3
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• pp.47-55
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• 2003

This paper presents the two field walls that demonstrate the effect of rainfall on the performance of soil-reinforced retaining wall. A field test wall constructed in Geotechnical Experimental Site at Sungkyunkwan University has been monitored for more than 8 months to study the long-term behavior of soil-reinforced retaining wall. The measured data showed a good correlation between rainfall and wall movement after wall completion. A case of failed soil-reinforced retaining wall also is presented to highlight the effect of rainfall on the performance of soil-reinforced retaining wall. Implications of the findings are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.54-63
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• 2018

In this study, the stability and economic feasibility of a MSE (Mechanically stability earth) wall with a pre-cast concrete pacing panel was investigated for a standard section of highway. Based on the design criteria, the MSE walls of the panel type were designed considering the load conditions of the highway, such as the dead load of the concrete pavement, traffic load, and impact load of the barrier. The length of the ribbed metal strip was arranged at 0.9H according to the height of the MSE walls. Because the length of the reinforcement was set to 0.9H according to the height of the MSE wall, the external stability governed by the shape of the reinforced soil was not affected by the height increase. The factor of safety (FOS) for the bearing capacity was decreased drastically due to the increase in self-weight according to the height of the MSE wall. As a result of examining the internal stability according to the cohesive gravity method, the FOS of pullout was increased and the FOS of fracture was decreased. As the height of the MSEW wall increases, the horizontal earth pressure acting as an active force and the vertical earth pressure acting as a resistance force are increased together, so that the FOS of the pullout is increased. Because the long-term allowable tensile force of the ribbed metal strip is constant, the FOS of the fracture is decreased by only an increase in the horizontal earth pressure according to the height. The panel type MSE wall was more economical than the block type at all heights. Compared to the concrete retaining wall, it has excellent economic efficiency at a height of 5.0 m or more.

• Journal of the Korean Geotechnical Society
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• v.29 no.11
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• pp.107-118
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• 2013

Geosynthetic reinforced soil (GRS) walls have been increasingly applied recently due to its numerous geotechnical engineering applications. However failure occurs in some cases of constructed GRS walls. These GRS wall failures are mostly due to the unpredictable characteristics of intensive rainfall. Hence, the need for new and innovative ideas for rehabilitation methods has been getting attention. This paper introduces a case study for the design and restoration method of collapsed GRS wall using Limit equilibrium and Numerical Analyses. Restoration method includes: (1) soil nailing without backfill excavation and (2) reconstruction with GRS wall after collapsed backfill excavation. Analyses results show minimal horizontal displacements and shear strain on the reinforced concrete facing for the restoration case with soil nailing. On the other hand, horizontal displacements are developed in the middle of the mortar block facing and shear strains are developed at the bottom facing with spiral curves for the reconstructed GRS wall after collapsed backfill excavation. Therefore, the collapsed GRS wall was restored with the soil nailing without backfill excavation and its construction procedures are discussed in this paper.

• Journal of the Korean Geosynthetics Society
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• v.4 no.4
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• pp.47-56
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• 2005

With the need of efficient site use retaining walls have frequently used. Of them dry cast modular block wall(MBW), in which geogrid and concrete block are used is getting popular because of its simplicity and economical efficiency of construction. However, since this method is based on the theory of earth pressure, sands with good quality should be used. In contrast, reinforced soil slope(RSS) that the slope is less than $70^{\circ}$ can use wider range of soil than MBW. A hybrid reinforced geo-structure might be a good alternative in view of overcoming difficulty obtaining soils with good quality as well as maximizing the efficiency of site use. This method is composed of reinforced block wall and reinforced soil slope. In this method, reinforced block wall is constructed up to a certain height vertically at ground boundary first. Reinforced soil slope is then constructed on the block wall subsequently. This paper introduces several technical points that should be taken into account in design and construction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.103-112
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• 2019

This study proposes a system to control the bulging phenomenon occurring in the reinforced earth retaining wall and to evaluate the reliability of the system by field experiment. In this study, drainage facilities were not installed in order to induce reinforcement earth retaining wall bulging, and the bulging was induced by rainfall. The induced bulging displacement exceeded the horizontal displacement criterion during the construction of FHWA. The retaining wall block was drilled and grouting was performed by inserting the nail into the drilling hole. The wire mesh is installed on the reinforcing surface and the head of the nail is connected horizontally so that the blocks of the reinforcing earth retaining wall can be supported with each other. In order to protect the reinforcements, the reinforcement surface was closed with shotcrete and a measuring device was installed to detect the progress of the displacement. After the reinforcement, the bulging were not found to progress any more, confirming the reliability of the system.