• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.13-22
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• 2021

Pile or column supported embankments have been increasingly employed to construct highway or railway embankments over soft soils. Piles or columns of stiffer material installed in the soft ground can provide the necessary support by transferring the embankment load to a firm stratum using a soil arching. However, there has been reported to occur a relatively large differential settlement between the piles and the untreated soils. Geosynthetic reinforced pile or column supported embankment (GRPS) is often used to minimize the differential settlement. Two dimensional finite element anlyses have been performed on both the column supported embankments and the geogrid reinforced column supported embankments by using a PLAXIS 2D to evaluate the soil arching effect. Based on the results obtained from finite element analyses, the stress reduction ratio decreases as the area replacement ratio increases in the column supported embankments. For the geogrid reinforced column supported embankments, the geogrid reinforcemnt can reduce differential settlements effectively. In additon, the use of stiffer geogrid is appeared to be more effective in reducing the differential settlements.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.4
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• pp.27-35
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• 2019

Purpose: As the improvement in quality of medical environment and the spatial consideration for the prevention of infection in the hospital have become increasingly important in the recent years, specific and practical planning for air conditioning room's area has become a major issue accordingly. However, the air conditioning room tends to be discussed focusing on technical factors such as air conditioning systems that are irrelevant to building plans, while discussions of most departments related to the medical functions have actively taken placed. Therefore, this study aims to investigate the factors influencing the planning for the air conditioning room area, and through subsequent analysis of the area of the air conditioning room, to propose a way to improve effective planning for the air conditioning room area. Methods: This study examines the case hospitals that fall into two types: each floor supply system and concentrated supply system, and compares and analyzes the air conditioning room area-related factors and the characteristics of changes in the interior of air conditioning room before and after remodeling through air conditioning floor plan of those case hospitals. Results: The air conditioning room can be classified into the net area of the functional space such as duct passages, and the public area such as aisle space, and of those the public area is an important factor in calculating the area of the air conditioning room. The public area of the air-conditioning room should not be planned considering only the spaces for mobile passage or maintenance activities, but should be planned taking into account internal changes such as expansion and replacement of equipment in the future from the beginning. Implications: When planning a medical facility, it is used as basic data for the planning of the air conditioning room area, which is a significant fixed factor in the initial setting.

• Journal of Industrial Technology
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• v.22 no.B
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• pp.191-197
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• 2002

This paper is experimental and numerical research results of performing centrifuge model tests to investigate the geotechnical engineering behavior of slag compaction pile as a substitute of sand compaction pile. In order to find the geotechnical engineering characteristics of the soft clay and the slag used in centrifuge model experiments, basic soil property tests, consolidation test, permeability tests and triaxial compression tests were performed. For centrifuge model tests, slags with changing relative density were used and their bearing capacity, stress concentrations in between pile and soft clay, settlement characteristics, and failure modes were investigated. As a results of centrifuge model tests, it was found that the bearing, capacity of model was increased with increasing density of slag pile and general shear failures were occured. Miniature soil pressure gauges were installed on model pile and soft ground respectively and thus vertical stress acting on them were measured. Stress concentration ratio was found to be in the range of 2.0~3.0. Bearing capacity obtained from the model test with slag was greater than that from the model test with a sand having the identical layout to each other. Thus it was confirmed the slag was an appropriate substitution of pile for sand.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.66-73
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• 2004

Prototype crushed-stone compaction pile(${\Phi}=700mm$) were constructed on specific test site. Static loading tests for crushed-stone compaction piles were performed. Based on the static loading test results, finite element analysis was performed using software PENTAGON 3D. Numerical analysis were done for the area replacement ratio($a_s$) of $20{\sim}70%$ and $a_s$ was varied as a step of 10%. In the single crushed-stone compaction pile, settlement was decreased as $a_s$ was increased. In the group pile, this tendency was similar. In the in-sit test and numerical analysis, as $a_s$ increased, the stress concentration ratio was increased. But $a_s$ in the numerical analysis were more than that of in-situ test, greatly.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.127-137
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• 2018

Gravel Compaction Pile (hereinafter referred to as GCP) is a ground improvement technique by packing crushed stones on fragile clay ground, pressing it, and forming stakes on the foundation. Although many researchers have analyzed stress behavior of GCP composite ground on domestic GCP technique using laboratory experiment and field experiment, analyses of stress behavior according to the difference of stiffness of mat foundation loaded on the upper foundation of GCP composite ground have not been done actively. Therefore, this study aimed to identify the stress concentration ratio in accordance with the difference of basis stiffness by interpreting figures. To perform this, replacement ratio was changed and modelled using ABAQUS, software for finite element analysis and analyzed the stress concentration ratio, amounts of settlement, and maximum amounts of horizontal displacement of composite ground in accordance with the difference of stiffness. An analysis showed that the stress concentration ratio of rigid foundation was highly assessed than unloading of flexible foundation in case of unloading, while amounts of settlement under flexible unloading condition were slightly higher than under rigid condition. This indicates that the characteristic of stress behavior on the different stiffness of upper foundation needs to be clarified. In addition, the maximum horizontal displacement was generated in a constant level regardless of the difference of stiffness.

• Journal of the Korean Geosynthetics Society
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• v.8 no.4
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• pp.41-46
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• 2009

In this paper, a series of laboratory chamber tests were performed to evaluate the effects of clays mixed into compaction piles due to confining stress of ground on consolidation promoting. For the tests, various compaction piles such as SCP, GCP, and RAPP (Recycled-Aggregate Porous concrete Pile) were used. The ground condition was simulated at 50% and 100% of degree of consolidation. Also, confining stresses were applied to the composite ground corresponding to those of 5m depth. The amount of mixed clays into each compaction pile were estimated by measuring the drainage from the saturated compaction piles. From the test result, it was shown that the drainage area of compaction pile was changing according to the consolidation condition. GCP showed the most change of drainage area as it has relatively large void ratio; however, the amount of change was decreased by progressing consolidation of ground.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.951-954
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• 2010

There are lots of soft ground improvement methods which is consist of different materials. In the analysis and design, composite ground method is usually regarded. Composite ground method considers the area replacement ratio as a key parameter to combine the physical and mechanical characteristics of tow different material. In this study, using composite material consist of three different materials which have different diameters, series of specific gravity test were performed according to KS F 2308, to investigate the applicability of composite ground method. As a result, it is found that composite material which is consist of fine grained soil and granular soil has a high applicability of composite ground method. This result means that, in estimating of ground properties of composite material which is consist of similar fine grained material such as cement mixing etc., composite ground method has a less applicability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.157-162
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• 2001

Recently, lots of studies for high flowing concrete have been suggested under practical use that it is only a way to solve the confronted problem. However, most studies have been concentrated on the manufacture method and properties of fresh concrete, but there is few studies for the durability of hardened concrete, specially for the freezing and thawing. Therefore this study is to investigate for the resistance of high-flowing concrete using finely ground granulated furnace blast slag to frost with experimental parameters, such as binder, ratio of replacement of granulated furnace blast slag, superplasticizer, curing method and blain surface area of granulated furnace blast slag.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.203-204
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• 2023

Recycled aggregate is an aggregate that satisfies the quality as an aggregate by crushing waste concrete and passing it through a separator. The government grants a floor area ratio of up to 15% and building height mitigation when more than 25% of the recycled building materials are used. In addition to environmental protection issues, it is necessary to actively utilize recycled aggregates that meet the standards to secure the business feasibility of buildings. This study attempted to derive the results according to the substitution rate by measuring the chloride ion diffusion characteristics based on the electrophoresis method.

• Journal of the Korean GEO-environmental Society
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• v.11 no.7
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• pp.5-14
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• 2010

The paper processed settlement analysis using Finite Elements Method(FEM). Because Stress Distribution Ratio has to be decreased, for settlement analysis of soft clay deposit improved by sand compaction piles(SCP). Back analysis was processed comparing the measured settlements of laboratory model tests and finite element analysis where the SCP treated area was assumed as mixed ground with clay deposit rather than being a composite ground. The paper proposes a methodology which employs a compression index($C_c$) for settlement analysis of soft clay deposit improved by sand compaction piles from the back analysis. This approach is applied to a field measurement case(A revetment founded on the SCP improved clay deposit with the replacement ratio of 45%).