• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.907-917
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• 2014

When conducting excavations after burying the soft ground, even if the retaining walls are installed, failure often occurs within backfill. In order to minimize the occurrences of failures, model test was performed after the installation of stabilizing piles to investigate the stabilizing effects. The model chamber is set up with clay foundation reinforced with and without stabilizing piles. During the excavation of clay foundation, the subsidence, pore water pressure, and soil pressure along the excavation were measured. As a result of the model test, the increase of excavation levels and the reduction of subsidence of back ground were observed with the stabilizing piles, compared to those without the stabilizing piles. The installation of stabilizing piles does not influence the pore water pressure change, but induces less subsidence rate. In addition, the depth of excavation has a significant effect on the back ground and it was evaluated that the maximum subsidence occurs as it is closer to the excavation point.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.135-143
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• 1990

Based on the mechanism of flat jack used to measure stresses in rocks, a prerssure gauge was developed to measure vertical stresses acting on the rigid boundary in a soil mass. This paper describes the mechanism of the newly built pressure gauge, the process of calibrating the response of this gauge, and its use to centrifugal model tests. By installing this gauge in centrifugal model experiments of reinforced earth retaining walls, vertical stress distribution at the rigid boundary of model wall was obtained and compared with theoretical prediction of trapezoidal vertical stress distribution.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.133-140
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• 2007

DCM (Deep Cement Mixing Method) has been applied to build structures such as self-supported earth retaining walls. DCM columns should be penetrability into the stiff layer to assure the self-supporting ability. On the penetration increase of blade attached to the DCM mixing tools, a spiral mixing blade has been revised. Penetration characteristics of spiral blades in the stiff soil layer were evaluated through Gimhae and Incheon areas. The spiral mixing blades could penetrate into the stiff soil layers which have the N-value of greater than 30 although the penetration rate is somewhat slow. Penetration characteristics and economical efficiency should be discussed to determine the critical depth of the spiral mixing blade because the penetration efficiency can decrease in the stiff layer in this paper.

• Journal of the Korean Geotechnical Society
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• v.22 no.8
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• pp.119-127
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• 2006

Granulated Blast Furnace Slag (GBFS) is produced in the manufacture process of pig-iron and shows a similar particle formation to that of natural sea sand and also shows light weight, high shear strength, well permeability, and especially has a latent hydraulic property by which GBFS is solidified with time. Therefore, when GBFS is used as a backfill material of quay or retaining walls, the increase of shear strength induced by the hardening is presumed to reduce the earth pressure and consequently the construction cost of harbor structures decreases. In this study, using the model sand box (50 cm$\times$50 cm$\times$100 cm), the model wall tests were carried out on GBFS and Toyoura standard sand, in which the resultant earth pressure, a wall friction and the earth pressure distribution at the movable wall surface were measured. In the tests, the relative density was set as Dr=25, 55 and 70% and the wall was rotated at the bottom to the active earth pressure side and followed by the passive side. The maximum horizontal displacement at the top of the wall was set as ${\pm}2mm$. By these model test results, it is clarified that the resultant earth pressure obtained by using GBFS is smaller than that of Toyoura sand, especially in the active-earth pressure.

• Journal of the Korean Geotechnical Society
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• v.22 no.5
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• pp.39-45
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• 2006

A field instrumentation for a recycled waste concrete geobag wall was performed to investigate the performance of the geobag wall, and uniaxial compression tests for a recycled waste concrete geobag were executed in laboratory. The strength of a recycled waste concrete geobag, the lateral earth pressure of a geobag wall, the horizontal deflection of a geobag wall, and the deformation of a backfill in geobag wall are mainly evaluated in this study. Based on the results of analysis on the measurements, it was found that the geobag wall displacement was within the recommendation for mechanically stabilized earth walls. It was also found that the use of a recycled waste concrete in geobag wall provides economical benefit, construction easiness, and good performance.

• Journal of the Korean GEO-environmental Society
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• v.14 no.12
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• pp.53-60
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• 2013

A new type of reinforced earth wall(REW) system is developed with vegetated facing which provides proper environment for long-term vegetation and also applicable to high retaining wall system. Vegetated retaining wall is a green alternative for retaining walls and an effective way to reduce heat island effect than conventional block or concrete systems. Several construction sites using vegetated facing is observed to monitor adaptation state of vegetation and estimate surface temperature of wall facing over two years. It was observed that a number of plants including Siberian chrysanthemum adapt well to the inside of the facing blocks because vegetation bag helps to keep a proper condition for vegetation. According to the results using thermographic camera, average surface temperature of vegetated facing is higher for all ranges of coverage ratio of vegetation. The increment of average surface temperature of vegetated facing is larger than that of non-vegetated facing when the air temperature rises, and vice versa.

• Geotechnical Engineering
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• v.12 no.6
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• pp.185-198
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• 1996

EPS is increasingly used as a filling material in soft ground. The beneficial effects of the use of EPS derive from minimizing the stress increment, which, in turn, increases the bearing capacity and reduces the settlement. EPS can also be used as a backfill material for retaining walls and abutments to reduce the horizontal earth pressure. However, there is no rational application for the selection of the EPS fill which is essential to the selection of the filling configuration and the settlement calculation. In this paper, therefore, the nonlinear numerical model developed from the results of triaxial compression tests is applied to the construction of EPS and verified through the comparison between the prediction and in-situ measurements.

• 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 Society of Safety
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• v.33 no.1
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• pp.73-80
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• 2018

According to the statistics publication of KOSHA, more than half of serious accidents at the construction sites were related to the temporary works and/or the temporary structures such as scaffoldings, shores, earth retaining walls, etc. The structural failures are occurred because of the overload acting on the structures or lack of performance of the one or more members of the structures. For the prevention of the collapse accidents relating to the temporary structures at the construction sites, we have to control construction processes not to occur the overload and also to control the performance and quality of each member of the temporary structures. MOLIT has amended the "Construction Technology Promotion Act" on Jan. 7th, 2015 to ensure the structural safety of the temporary structures. According to the Act, the designers of the construction design projects should check the structural integrity of the structures including the temporary structures and the construction companies have to let 'the Relative Professionals' confirm the structural integrity of temporary structures, the shores(${\geq}5m$ high) and the scaffolds(${\geq}31m$ high), before construction. Also, MOLIT has amended the "Regulation for Construction Technology Promotion Act" on Jul. 4th, 2016 for quality management and testing of temporary equipments. According th this regulation, the construction companies and supervisors should manage and test the temporary equipments before using them. In this paper, the standard drawings of the shores(< 5 m high) and the scaffolds(< 31 m high) and the amended "Business Guideline for Quality Management of Construction Work" are presented. As the result of this study, MOLIT noticed the amended "Business Guideline for Quality Management of Construction Work" on Jul. 1st, 2017.