• Journal of the Korean Geotechnical Society
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• v.17 no.2
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• pp.113-122
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• 2001

소성이 높은 고함수비를 갖는 준설점토에 대한 침강 및 자중압밀 특성에 대한 연구는 국내외에서 활발하게 진행되고 있는 반면, 비소성 준설토에 대한 침강, 퇴적 특성에 대한 연구는 국내뿐만 아니라 국외에서도 거의 진행되지 않고 있는 실정이다. 일반적으로 비소성 준설토는 침강 및 퇴적 단계에서 고소성의 준설점토와 다른 거동 특성을 나타낸다. 본 논문에서는 비소성 준설토에 대한 실내 침강압밀실험을 실시하여 비소성 준설토의 퇴적 및 침강 현상을 제시하였다. 또한 퇴적고 관찰이 이루어진 준설토에 대한 퇴적특성 분석을 통하여 계면고 관찰이 이루어진 준설토에 대한 퇴적 현상을 해석하였으며, 이를 통하여 비소성 준설토에 대한 침강 및 퇴적 거동을 예측하였다. 또한 초기 및 최종 퇴적고에 대한 상관관계, 최종 퇴적고 및 최종 계면고에 대한 상관관계 분석을 통하여 비소성 준설토의 거동 특성을 분석하였다.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.89-98
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• 2003

A 5∼12m thick tideland has been created in front of a new sea-dyke due to the rapid sedimentation occurring for 22 years. It is confirmed from theoretical analysis and soil tests that the deposit is in under-consolidation state. An analysis shows that when the average sedimentation rate is over 1-5cm/year for a soil with $c_v$=0.0005-0.001$cm^2$/s, excess pore water pressure exists in the deposit. It is known that the lower sedimentation rate than average in the initial deposition stage results in lower dissipation of excess pore pressure and vice versa. It is emphasized that under-consolidation behavior should be taken account in settlement analysis because structures founded on such deposits give higher settlements.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.219-238
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• 1999

In the present study, laboratory tests including the seepage-induced consolidation test, suction test, and desiccation shrinkage test are performed to investigate characteristics of the desiccation shrinkage in reclaimed hydraulic fills. Soil samples for laboratory tests are obtained from three sites (districts of Haenam, Kogeum and Koheung in Chunnam area). Desiccation shrinkage settlement caused by three dimensional volume change is numerically evaluated using finite difference technique based on the governing equation proposed by Abu-Hejleh & Znidarcic. Also characteristics of the desiccation shrinkage analyzed from the test results are used as input data for numerical evaluations. Further predicted total settlements including the self-weight consolidation settlement are compared with values measured at the site of Haenam district. Finally, effects of parameters related to the desiccation shrinkage on settlements are examined.

• Journal of the Korean Geotechnical Society
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• v.27 no.11
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• pp.5-15
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• 2011

This paper presents two analysis methods for characterizing the non-linear finite strain consolidation behavior of highly deformable dredged soil deposits along with the fundamental parameters obtained in the companion paper; that is, the zero effective stress void ratio, the non-linear relationships of void ratio-effective stress and void ratio-hydraulic conductivity. The simplified Morris's analytical solution (2002) and the widely recognized numerical program, PSDDF (primary Consolidation, Secondary Compression, and Desiccation of Dredged Fill) for both single and double drainage conditions are adopted in this paper to verify a series of laboratory experiments for self-weight consolidation of the Incheon clay and Kaolinite. The comparisons show that the analysis methods proposed herein can properly simulate the long-term non-linear finite strain consolidation behavior for dredged soils in the field. In addition, a case study for the artificial Craney Island has been conducted to illustrate the importance of obtaining appropriate non-linear finite strain consolidation parameters and the applicability of PSDDF in promoting dredged soil disposal.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.31-38
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• 2009

A continuous, fast, and convenient experimental method, replacing recent tests such as standard oedometer or self weight consolidation test, is needed for the determination of the consolidation behavior of unformed soft soils. This study introduced the seepage induced fast consolidation test using the flow pump technique. It can obtain the consolidation characteristics of unformed soft soils conveniently and fast. The seepage induced consolidation test apparatus consists of a modified triaxial cell, differential pressure transducer, flow pump, and displacement transducer. The test continuously proceeds with starting seepage forces induced consolidation, loading consolidation, and permeability test on the same sample. In addition, this test result was compared with the standard oedometer test result to make this method valid. From this study it was found that this method is a convenient and time saving effective method for obtaining data required for calculation of consolidation settlement of unformed soft soils.

• Journal of the Korean GEO-environmental Society
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• v.3 no.1
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• pp.67-77
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• 2002

Volume change of the dredged soils is composed of the volume loss of soil particle flowing over an outflow weir with water and settlement due to both the self-weight consolidation in reclaimed layer and the desiccation at the surface of reclaimed layer. In order to estimate the amount of soil particles flowing over an outflow weir with water, the evaluation procedure of loss ratio of the dredged soils is proposed in the present study based on the Marsal's modified breakage theory and the results of hydrometer analyses. To verify a validity of the proposed procedure, evaluated loss ratio is compared with results from the other existing methods. The model test results and those of field test were compared and analyzed. Also, the variation of soil loss ratio was examined through the model test in the lab.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.123-136
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• 2004

Terzaghi's one-dimensional consolidation theory has some important assumption, which can't be applicable to predict the behavior of soft clay ground. Especially, predictions using infinitesimal strain and linear material function related with permeability can give rise to mistake in comparison with the result of real behavior in site. For this reason, Gibson et al. established a rigorous formulation for the one-dimensional nonlinear finite strain consolidation theory, which can consider non-linearity of material function. But it is difficult to apply this theory to predict the behavior of common soft clay ground with vertical drain. In this study, consolidation model which can consider the vertical and horizontal flow of a fully saturated clay layer, self-weight of soil and nonlinear characteristics of compressibility and permeability are derived. Numerical analysis scheme, which can be applied to consolidation analysis by derived consolidation model in this study was developed. The characteristics of material function were examined using laboratory testing such as standard consolidation test, Rowe-cell test and modified consolidation test.

• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.27-39
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• 2005

A finite difference program with 3-D governing equation expanded from 1-D self-weight consolidation is developed to analyze the consolidation behavior of surface dredged soil with horizontal drains. Various boundary conditions with horizontal drains and seepage pressure of pore water infiltrated to the drains are considered in the program. A laboratory soil chamber experiment for the consolidation of dredged soil is performed to validate the program and the measured settlement-time result is compared with the one predicted by the program. The influence of design conditions of horizontal drains such as horizontal installation spacing, installation depth and number of drain layers, on the consolidation is analyzed.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.149-156
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• 2000

Sedimentation and self-weight consolidation tests in cylinder and large model tank and field measurement such as settlement and pore water pressure at each layer by wireless automatic instrumentation system were carried out to investigate the behaviour of dredged marine clay fill. The consolidation behaviour for each reclaimed layer was analyzed from these measured data and numerical analysis result using finite strain consolidation theory. It was fond from this study that the consolidation behaviour of dredged clay fill is heavily dependent on the filling process.

• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.41-48
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• 2005

The gravitational consolidation behavior of the dredged ground with horizontal drains is analyzed using a finite difference program developed for self-weight consolidation analysis with horizontal drains. The influence of area and direction of horizontal drains on the consolidation time and settlement is analyzed. Various field conditions such as the non-treated ground below horizontal drain installed ground, the accumulation of drained water at the end of horizontal drains, are also included in the analyses. It was found that a slight decrease of consolidation time is resulted in the twice increase of the sectional area of drains. Installing drains vertically can reduce the consolidation time more significantly than installing drains horizontally. The analyses showed quantitatively that the non-treated ground below the horizontal drain installed ground has much influence on long term consolidation settlement, and the accumulation of hydraulic head at the end of horizontal drains results in the increase of consolidation time and insufficient consolidation.