• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.264-271
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• 2005

Sand pile method, such as sand drain method and sand compaction pile method, has been popularly used as an improvement method for soft clay grounds. The effect of accelerating consolidation of soft clay grounds has been evaluated with Barron's solution. By the way, the consolidation behavior of soft clay ground with sand piles strongly depends on both the nonlinear mechanical interaction between sand piles and surrounding clays and the degradation permeability of clays. In this paper, the method for determining consolidation parameters of soft clay ground with sand drains by using Barron's solution was proposed, through a series of numerical simulations. Through the method, the change in both volume compressibility and permeability during consolidation was reasonably evaluated.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1047-1054
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• 2005

The purpose of this study is the understanding to changes in the characteristic of soil structure and classification, atterberg limits, undrained shear strength and consolidation of clayey soil dependent on pH of soil pore water. A series of tests including consistency tests, uniaxial compressive tests, vane tests and oedometer tests are performed on. The test results indicated that pH changes in the soil pH resulted in changes in the soil structure and classification, stress-strain behavior. Specially, when pH is conditioned to 7, liquid limit, undrained shear strength and preconsolidation pressure are the largest.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1191-1198
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• 2005

To designer and builder because drilling log, last accomplishment of boring, is made by subsurface expbration of site person in charge base information intermediate delivered by unified style as is concise be. However, make and is using drilling log that is dissimilar in each engine without style or creation standard unified in the case of domestic. Civil engineers lose an opportunity that can get more informations thereby or problem of inappropriate design, construction often happens. In this study, analyzed drilling log style examination of inside and outside of the country and merits and demerits to solve problem of these design and construction. And study improvement item on recording contents and suggested consistent drilling log standard illustration plan.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1538-1545
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• 2005

Theoretical and experimental result studies of the unconfined penetration test (UP) method are conducted to suggest a new test method by improving the UP method for determination of the tensile strength of compacted fine-grained soils. From the theoretical aspect, the tensile strength of the specimen is estimated from the maximum load by the theory of perfect plasticity with assumptions, sufficient local deformability and modified Mohr-Coulomb failure criterion. Experimentally, some factors including relative size of specimen-disc, disc diameter, and loading rate are needed more study, because these factors significantly affect the results of tensile strength. Improvement of the alignement between two discs and specimen in the UP test is also necessary to eliminate the error due to eccentrically loading.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.966-973
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• 2005

The stress concentration ratio in accordance with area replacement ratios were considered as core elements of design. However, the stress concentration ratio will be vary depends on progress of consolidation in clay ground. And, since it is not sure to know the affecting factors accurately, the value is decided based on field experiences. To use SCP method more effective and correspond to soil improvement, the decision on proper area replacement ratio through the exact stress concentration ratio is very important. Accordingly, a numerical analysis on influence of various factors that needed to make rational designing guide for decision of proper area replacement ratio to stress concentration ratio was executed in this study.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.475-482
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• 2004

The purpose of this paper is to study on the investigation of abandoned waste landfill for rehabilitation. The geotechnical and environmental field and laboratory tests for wastes dumped at municipal site were carried out. Testing wastes were sampled at the illegal landfill site The various samples such as waste. soil, groundwater, gas, leachate were taken in the landfill site. As a result of this study, the engineering properties and concentration of samples were investigated The result of this study was used for introduction the rehabilitation method and treatment of unregulated closed landfill.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.469-474
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• 2004

본 연구는 유류로 오염된 지반을 개선하는데 초음파를 사용한다는 점에 초점을 둔다. 초음파의 원리는 고체의 재료가 음파의 좋은 전도체라는 사실에 근거를 두고 있다. 초음파에 의한 정화는 초음파의 적용에 의해 재료의 표면이 변화되고 그것에 의해 오염물질이 제거된다는 것을 의미한다. 본 연구에서는 초음파의 지속, 간극률, 초음파력, 입자의 크기와 유속율 같은 초음파 취급에 영향을 끼치는 요소들을 고려하여, 초음파를 쓴 것과 쓰지 않은 오염된 흙을 다룬 결과를 비교 분석하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.897-903
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• 2004

Waste lime used in this study is producted as a by-product in the manufacturing process of making $Na_2CO_3$ from local chemical factory in Incheon. Currently about 320 millon tons of waste lime are accumulated and annually 100,000 tons are producted. Reuse of waste lime mixed with soil for banking and backfill materia in civil works was analysed in this study. This study was Carried out to investigate the geotechnical and environmental characteristics on field application. Field investigations were conducted on the road construction site in Incheon. This study presents the results of the engineering characteristics in field test and the leaching characteristic of waste lime in laboratory column tests. Countermeasure for reduction of environmental effects was suggested from the test results.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.873-881
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• 2004

A serious of EK remediation tests on contaminated soil are performed under unsaturated conditions and analyzed for electrical potential, water content, pH and so on. The results indicated that electrical potential and pH distributions in the sample are dependent on the amount and inward/outward flow of hydrogen ion. Specially, for the closed system the water content is largely decreased with the flow of hydrogen. The maximum electrical conductivity is measured at the catholyte of CEM(Sealing) test and directly related to the remedial efficiency. Although pHs in the region near to the anode are similarly developed, the different concentration of lead is measured with the electrical gradient contrary to the lead concentration dependent on pH within the sample.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.890-896
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• 2004

This study is intended as an investigation of the EK remediation characteristics of natural soil with treatment time under unsaturated conditions. EK tests are performed under the voltage gradient of 1V/cm, the degree of saturation of 82.8%, and the installing of cation exchange membrane. It was found from the results that the acid front is initially transported at 0.75cm/day and then continuously degreased until the transport velocity of the acid front is balanced to the velocity of the base front. The residual lead concentration indicated the maximum value at the treatment time of lOdays, then the increasing of treatment time largely decreases the concentration within the sample though electromigration than electroosmosis.