• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.95-100
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• 2000

When compared with conventional retaining wall system, there are many advantages to reinforced soil such as cost effectiveness, flexibility and so on. The use of reinforced soil have been increased in the last 17 years in Korea. In this study, a full-scale reinforced soil with rigid facing were constructed to investigate the behavior of reinforcing system. The results of soil pressure and strain of reinforcement during construction are described. The influence of compaction on soil pressure and strain of reinforcement is addressed. The results show that lateral earth pressures on the wall are active state during backfill. It is obtained that the lateral soil pressure depends on the installation condition of pressure cell and construction condition. It is also observed that maximum tensile strains of reinforcement are located on 50cm to 150cm from the wall. Long-term measurement will be followed to verify the design assumptions with respect to the distribution of lateral stress in the reinforcement

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1623-1629
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• 2008

The purpose of this research is to assess the application of recycled-aggregate that is gained from construction wastes as the material of compaction pile method. At the same time, the development of the new technique rectifies defects of the existing compaction pile method for soft ground improvement. In this research, model tests were conducted for analyzing the effect of the soft ground improvement by porous concrete pile using recycled aggregate. Through the results of the model tests, the behavior of settlement on composition ground with surcharge pressure were elucidated.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.85-99
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• 2015

It is urgent to redevelop the superannuated reservoir levee through the levee raising for countermeasure to climate change and improvement of storage capacity of reservoir. However, low compaction degree of the raised reservoir levee owing to poor construction condition leads to degradation of the stability of the reservoir levee on seepage and earthquake. In this study, seepage and seismic behavior of raised reservoir levee with low compaction degree was evaluated through numerical simulation. From the simulated results, water level raising possibly induces crack and/or sinkhole on the surface of the poorly-compacted raised reservoir levee owing to the increase of the subsidences at the crown and the front side of that. In addition, relatively larger displacement and acceleration response at the front side of raised reservoir levee in seismic condition may degrade overall stability of reservoir levee. Therefore, reasonable construction management for the compaction of the raised reservoir levee is required for ensuring long-term stability on seepage and earthquake.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.936-942
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• 2013

This paper presents the results of laboratory tests conducted to investigate the effectiveness of applying methodology of a sand compaction(SCP) and a gravel compaction pile(GCP) on soft ground. The test conditions involved relatively low replacement ratios (=10, 20, and 30%) of a pile to unit cell at 1g (gravity acceleration) level. Results revealed that GCP significantly enhanced bearing capacity, settlement reduction, and consolidation rate compared with SCP.

• Computers and Concrete
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• v.5 no.4
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• pp.329-342
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• 2008

A local behavior law, which includes elasticity, plasticity and damage, is developed in a three dimensional numerical model for concrete. The model is based on the Discrete Element Method (DEM)and the computational implementation has been carried out in the numerical Code YADE. This model was used to study the response of a concrete slab impacted by a rigid missile, and focuses on the extension of the compacted zone. To do so, the model was first used to simulate compression and hydrostatic tests. Once the local constitutive law parameters of the discrete element model were calibrated, the numerical model simulated the impact of a rigid missile used as a reference case to be compared to an experimental data set. From this reference case, simulations were carried out to show the importance of compaction during an impact and how it expands depending on the different impact conditions. Moreover, the numerical results were compared to empirical predictive formulae for penetration and perforation cases, demonstrating the importance of taking into account the local compaction process in the local interaction law between discrete elements.

• 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.

• Nuclear Engineering and Technology
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• v.34 no.1
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• pp.60-67
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• 2002

The effects of ball-milling time(0 ~4 hrs) have been investigated on the change of powder characteristics, compaction behavior (compaction pressure range : 200 ~400MPa) and sinterability (1700'c in Ha atmosphere) of two different UO$_2$ powders (ex-ADU and ex-AUC) prepared by the wet process. It is observed that, while the ex-ADU UO$_2$ was little affected, the ex-AUC UO$_2$ was largely affected by the ball-milling treatment. This may be attributed to the characteristics of particle size formed during the preparation step, i.e.., the former has a small average size of about 1.0${\mu}{\textrm}{m}$, while the latter has a relatively large average size of about 301n. It appeared that the effective size reduction by ball-milling treatment is limited to the particle size larger than l${\mu}{\textrm}{m}$, and to the extent of maximum decrease in size of about 0.5tn. In the case of ex-AUC UO$_2$, it is observed that the particle size decreased with ball-milling time and green density and sintered density of the pellets prepared from ball-milled powder increased compared with those of pellets prepared from the as-received powder under the same conditions. This may be attributed mainly to the fine particles formed during the ball-milling treatment.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.356-364
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• 1998

The dependence of green and sintered densities of Zirconia-Toughened Alumina ($ZTA:\;Al_2O_3/\;15\;vol{%}\;ZrO_2$) on the properties of spray-dried granules was studied thoroughly to establish the optimum compaction condition leading to high reproducibility in the light of sintered density. The sphericity, mean size, degree of hollow occurrence and moisture content of spray-dried granules were largely different in between the granule containing binder and the ones with no binder. The effect of these differences in the characteristic of granules on the compaction behavior was examined in terms of the compaction pressure from 80 MPa to 120 MPa 10 MPa increment and the compaction method, i.e., uniaxial and cold isostatic pressing. This work confirmed that the reproducibility of sintered density caused by the variation of granule property could be improved by the optimization of compaction process. The variation of sintered density was controlled within 1 % deviation by compacting the granules under a relatively low pressure of 80 MPa in an uniaxial forming and subsequent cold isostatic pressing at high pressure of 500 MPa.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.04a
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• pp.18-19
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• 1997

• Composites Research
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• v.31 no.1
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• pp.23-29
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• 2018

The RFI process can be applied to very thick structures without limiting the resin viscosity. When the proper thickness of the resin film cannot be set, the resin film creates either the non-impregnated section or the excessive resin contents and this leads to the deterioration of mechanical properties. Therefore, this study proposed a method for setting the resin film thickness in the RFI process. The fiber compaction behavior test was proposed by setting the proper resin film thickness and the properties of composites were evaluated through short beam shear strength test, compression test and porosity measurement to verify the proposed method. The evaluation of physical properties of composites was conducted and an appropriate level of resin film thickness was found based on the results of fiber compaction behavior test.