• Journal of the Korean Geotechnical Society
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• v.24 no.7
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• pp.43-50
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• 2008

Structures are frequently built on a dredged clay layer overlaid by a soft marine clay deposit in coastal areas of Korea. Large consolidation settlement usually occurs in the case and this may cause damages of super-structures. So, the evaluation of long-term consolidation settlement is very important in design and construction. Therefore, in this study, a long-term consolidation characteristics of marine dredged clays are investigated. Firstly, the relationship of $C_{\alpha}/C_c$ on marine dredged clays near Gwang-yang Port was evaluated. Secondly, long-term consolidation characteristics of the pseudo-preconsolidated ground were evaluated.

• Geomechanics and Engineering
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• v.7 no.1
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• pp.105-131
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• 2014

In this paper, the effects of variability of smear zone characteristics induced by installation of prefabricated vertical drains on the preloading design are investigated employing analytical and numerical approaches. Conventional radial consolidation theory has been adopted to conduct analytical parametric studies considering variations of smear zone permeability and extent. FLAC 2D finite difference software has been employed to conduct the numerical simulations. The finite difference analyses have been verified using three case studies including two embankments and a large-scale laboratory consolidometer with a central geosynthetic vertical drain. A comprehensive numerical parametric study is conducted to investigate the influence of smear zone permeability and extent on the model predictions. Furthermore, the construction of the trial embankment is recommended as a reliable solution to estimate accurate smear zone properties and minimise the post construction settlement. A back-calculation procedure is employed to determine the minimum required waiting time after construction of the trial embankment to predict the smear zone characteristics precisely. Results of this study indicate that the accurate smear zone permeability and extent can be back-calculated when 30% degree of consolidation is obtained after construction of the trial embankment.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.57-65
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• 2007

Effects on the stiffness of the embankment and sandmat on the construction safety of road embankment was investigated in this study by the numerical experiments using FEM. Two points was mainly focused in this study especially. First the deformation characteristics by the change of the stiffness of sand mat and embankment was investigated by the analyzing the consolidation settlement at the center of the embankment and the lateral displacement at the toe of the embankment. And, the effect of the stiffness on the stress distribution characteristics was also investigated in this study. Furthermore, slope stability analysis was carried out to gain the safe factor by change the stiffness of the sandmat and the embankment. The objective of the study is supplying the result of the numerical experiments for the geotechnical engineers who use the FEM for the safety design of the soil structures. As a result, the stiffness of the superstructures greatly affects on the deformation characteristics both in consolidation settlement and lateral displacement. However, it can be aware that it is not dominants to the stress distribution in the aspect that the no changes in the residual excess pore water pressure. Therefore, the decision of the stiffness has to be carried out deliberately considering not only the consolidation the magnitude of the settlement and the lateral displacement, but the slope stability.

• Journal of the Korean GEO-environmental Society
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• v.7 no.3
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• pp.5-19
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• 2006

The secondary consolidation settlement of soft clay is generally very little compared to the total settlement and occurs very slowly during long-term period. However the secondary consolidation settlement is comparatively large amount in organic and heavily compressed clay and is a very important engineering factor. In order to reduce residual settlements in reclaimed soft ground, the preloading method is often used. In this study, in order to determine reasonable long-term settlements of large reclaimed site, laboratory incremental loading consolidation tests and surcharging consolidation tests are performed. Sampling was done at Incheon area of west coast and Gwangyang area of south coast in Korea. The characteristics of secondary consolidation have obtained through laboratory tests and analyzed systematically to predict long-term settlements. Additionally, the location data and laboratory test results are correlated by using GIS(geographic information system). The secondary consolidation settlement of the site was predicted based on D/B and the operation technique and estimation technique of space of GIS.

• Journal of Information Technology Services
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• v.10 no.4
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• pp.281-293
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• 2011

Server consolidation and virtualization have become an integral part of IT planning to reduce TCO cost and ensure the high availability for customer, enlarge the flexibility to computing resource in today' enterprise data centers. In spite of having the variety advantages of server consolidation and virtualization, they cause many problems such as the software licensing issues, virtual server sprawl, network complexity issues, hardware start-up costs, and failover costs. In particular, software licensing problem brings about the serious results in operating of data center and also presents a significant challenge to virtualization because many vendors have realized that licensing policies applicable to physical systems are not compatible with virtual machines. So, the IT planers must be considering this problem before they conducts the server consolidation and virtualization. In this paper, we proposed the efficiency strategy of SW licensing for server consolidation and virtualization analyzing the N-Datacenter case in Korea. As a result, we suggest the two strategies as technical and management/contract aspect. First, as the technical aspect, we propose i) the adaptation of suitable licensing for virtualization, ii) differentiation of license according to the characteristics of server, iii) the core distribution of licenses to minimizing. Second, as the management/contract aspect, we suggest following three things. i) The existing license agreement is changed to the right licensing for virtualization. ii) The license agreement is contracts the active focused. iii) When a new contract should be added to virtualization provisions.

• Journal of the Korean Geotechnical Society
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• v.29 no.3
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• pp.61-70
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• 2013

Evaluation of permeability and coefficient of consolidation of clayey sand is critical in analyzing ground stability or environmental problems such as prediction of pollutant transport in groundwater. In this study, permeability tests using a flexible wall permeameter are performed to derive the coefficient of consolidation and permeability of reconstituted soil samples with various mixing ratios of kaolin clays and two different types of sands, which are Jumunjin and Ottawa sands. The test results indicate that the coefficient of consolidation and permeability plots linearly against clay contents in semi-log scale graphs for low clay mixing ratios ranging between 10 to 30%. It is also demonstrated that coefficient of consolidation and permeability of sand and clay mixture are dependent on the soil structure. Contrary to previous findings, the permeability is shown to be independent of the void ratio at low mixing ratios, which can be classified as non-floating fabric. The permeability decreases with the void ratio for floating fabric.

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.29-36
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• 2011

In this study, settling experiment was performed about cohesive and sandy soils among representative sample expected to dredge and dump for analysis of settling and consolidation characteristic. The analysis showed the definite difference between cohesive soils and sandy soils of relationships with settling and consolidation coefficient, a water content, interfacial heights. But directly after a dredged reclamation, prediction results about a initial volume change showed that cohesive soil of a water content change was decreased rapidly as time goes by, but sandy soils made no difference in a water content change. Results were compared and analyzed with the settling and consolidation coefficient and a initial settling velocity by real soil amounts for a feasibility check about test conditions applied to these experiment: we judge that test conditions are appropriate, each material by such these analyses suggests the scope of settling and consolidation coefficient, average and the representative relational formula.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5C
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• pp.333-342
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• 2006

In this study, a consolidometer for radially inward drainage under constant rate of strain (CRS) loading was developed. Their analytical solutions for evaluating consolidation characteristics of soils were also derived. With reconstituted kaolinite samples, comparative tests of the developed CRS loading consolidation in radially inward drainage together with incremental loading (IL) consolidation in radially inward, vertical and radially outward drainages and CRS loading consolidation in radially outward and vertical drainages were carried out. From the test results, It is confirmed that the results of the developed consolidometer were not only in good agreement with those of other consolidation tests but also they were more stable and reliable with less sample disturbance effect.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.03a
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• pp.135-142
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• 1998

• Geomechanics and Engineering
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• v.6 no.5
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• pp.437-453
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• 2014

This paper studies the swelling and strength characteristics of unimproved and improved expansive soils in terms of the swell potential, swelling pressure, rate of secondary swelling, unconfined compressive strength and California bearing ratio (CBR). The admixtures used in this study are locally available cement and fly ash. The soils used in this study were taken from the Mae Moh power plant, Lampang Province, in northern Thailand. A conventional consolidation test apparatus was used to determine the swelling of the soil specimen. The optimum admixture contents are determined to efficiently reduce the swelling of unimproved soil. The rate of secondary swelling for unimproved soil is within the range of highly plastic montmorillonite clay, whereas the specimens improved with optimum admixture contents can be classified as non-swelling kaolinite. A soil type affects the swelling pressure. Expansive soil improvement with fly ash alone can reduce swelling percentage but cannot enhance the unconfined compressive strength and CBR. The strength and swelling characteristics can be predicted well by the swelling percentage in this study.