• Geotechnical Engineering
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• v.14 no.5
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• pp.181-190
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• 1998

One-Dimensional Nonlinear Consolidation Model(NCM) ivas developed by using an Extended Power Function Model, which could represent the compressibility of soils. A nonlinear finite element program for NCM was developed to analyze the porewater pressure dissipation and the settlement of saturated soils. Parameters used in compressibility model could be easily obtained from conventional oedometer test data. This model has been applied to Yansan-Mulgum area for the comparison with the results of CONSOL program and that of Terzaghi theory. A Good The rates of consolidation predicted by this model and CONSOL were faster than that of conventional Tergaghi theory, for they consider the nonlinear characteristics of soils. Consolidation curves of this model were located between Terzaghi and CONSOL curves. Consolidation curves near drainage boundary, where effective stress valied rapidly, seemed to reflect the variations of compressibility of sails. Consolidation curves near drainage boundary obtained from this model were composed of two parabolic curves. Intersection of the parabolic curves occurred when effective stress reached the value of preconsolidation stress. Moreover, thin model could be used to represent the effect of magnitude of applied load. whereas CONSOL and Terazghi theory could not.

• Journal of Industrial Technology
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• v.28 no.A
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• pp.11-17
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• 2008

Applicability of hyperbolic settlement prediction method to consolidation settlement in the dredged and reclaimed ground was assessed by analyzing results of centrifuge tests modelling self-weight consolidation of soft marine clay. From literature review about self-weight consolidation of soft marine clays located in southern coast in Korea, constitutive relationships of void ratio - effective stress - permeability and typical self-weight consolidation curves with time were obtained by analyzing centrifuge model experiments. For the condition of surcharge loading, exact solution of consolidation settlement curve obtained by using Terzaghi's consolidation theory was compared with results predicted by the hyperbolic method. It was found to have its own inherent error to predict final consolidation settlement. From results of analyzing thc self-weight consolidation with time by using this method, it predicted relatively well in error range of 0.04~18% for the case of showing the linearity in the relationship between T vs T/S in the stage of consolidation degree of 60~90 %. However, it overestimated the final settlement with large errors if those relation curves were nonlinear.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.121-128
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• 2005

This paper introduces a method of predicting the behavior of compacted soil with an unsaturated soil mechanics by considering the effect of suction as an increasing consolidation yield stress. Two kinds of experiments were conducted. One is a series of static compaction tests to monitor the suction, and the other is a series of compression tests on compacted soil without soaking. The results of our tests indicate that it is possible to derive the distribution of suction on compaction curves and to hypothesize the changes in void ratio in the compression tests that depends on the suction. In addition, a new method is proposed to estimate the consolidation yield stress of compacted soil with a simple chart including compaction curves.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.143-151
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• 2005

This paper presented a method to estimate the consolidation yield stress of compacted soil with an unsaturated soil mechanics, especially considering the effect of matric suction. Then two kinds of experiments were conducted. One is a series of static compaction tests to monitor the matric suction, and the other is a series of consolidation tests on compacted soil without soaking. The results indicate that it is possible to derive the distribution of matric suction on compaction curves and to hypothesize the changes of the void ratio depending on the matric suction in the consolidation tests. With this experimental results, a new method was introduced to estimate the consolidation yield stress of compacted soil including compaction curves.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.240-247
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• 2005

In order to analyze effects of strain rate on consolidation characteristics on Busan clay, a series of constant rate of strain(CRS) consolidation tests with different strain rate and incremental loading test(ILT) were performed. From experimental test results, it was found that the preconsolidation pressure was dependent on the corresponding strain rate occurred during consolidation process. Also, consolidation curves normalized with respect to preconsolidation pressure gave a unique stress-strain curve. Coefficient of consolidation and permeability estimated from CRS test had a tendancy to converge to a certain value at normally consolidated range regardless of strain rate. An increase in excess pore pressure without change of total stress was noted on the incremental loading test after the end of loading.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.140-145
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• 2010

Consolidation in cohesive soils mainly focuses on compressibility of soils, but it affects solute transport in some cases. The consolidation process takes on particular significance for fine grained soils at high water content, such as dredged sediments, but has also been shown to be important for compacted clay liners during waste filling operation. Numerical investigation using CST1 and CST2 was reviewed on consolidation-induced solute transport in this paper, especially with the development of CST2 model, verification by comparing experimental results with numerical simulations, and cases studies regarding transport in a confined disposal facility (CDF) and during in-situ capping. The importance of the consolidation process on solute transport is accessed based on simulated concentration or mass breakthrough curves. Results indicate that neglecting transient consolidation effects may lead to significant errors in transport analyses, especially with soft contaminated cohesive soils undergoing large volume change.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.370-375
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• 2005

This paper describes a systematic way of identifying the horizontal coefficient of consolidation for clayey soil under undrained condition and silty soil under partial drained condition by applying an optimization technique to the early part of dissipation data measured from the self-boring pressuremeter strain holding test. An analytical solution developed by Randolph & Wroth (1979) was implemented in normalized form to express the build-up and dissipation of excess pore pressures around a pressuremeter as a function of the rigidity index. Horizontal coefficient of consolidation was determined by minimizing the differences between theoretical and measured excess pore pressure curves using optimization technique. It was found that the proposed optimization technique can evaluate in-situ horizontal coefficient of consolidation rationally, which is similar with that obtained from the piezocone dissipation test. Furthermore, proposed method can evaluate appropriate coefficient of consolidation for soil under partially drained condition.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.105-114
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• 2004

Consolidation characteristics have been investigated by using Rowe cell consolidation tester for dredged soil, which is more than two times as much as the liquid limit. To examine the effects of variation of water content on consolidation characteristic, tests were carried out varying the initial water content from $100\%\;to\;150\%.$ The results were compared with the consolidation characteristics of remolded clay. The test results showed that the hither the initial water content of dredged clay was, the more noticeable the non-linear behavior of e-log P curves occurred. The variation of the gradient was apparent to load stage 40kPa and became less apparent after load stage 80kPa on the e-log P curves. Ratio of compression index stayed within the range suggested by Mesri and variation of initial water content has hardly influenced the coefficient of consolidation. On the contrary, it was found that the magnitude of consolidation load affects the vertical coefficient of consolidation. The variation of stratum thickness during consolidation processing needs to be taken into consideration since hydraulic fill would go through a much larger scale strain than land soil when it is subject to a load. In this study, the consolidation period considering the variation of stratum thickness was analyzed and the results were compared with those of existing consolidation studies which did not consider the variation of stratum thickness. According to the results of the study, the consolidation period of the ground with a larger strain was calculated more close to observed value in case of Mikasa theory which takes the variation of stratum thickness into consideration.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.6
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• pp.51-63
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• 2023

To improve the problem that the settlement curve of the consolidation theory of Terzaghi does not match well with the actual settlement curve, we included a secondary compression settlement and analyzed it by varying the beginning point and then obtained the following results. The current methods of calculating the compression index from the  log𝜎 curve and the coefficient of consolidation from the time-dependent settlement curve for each consolidation pressure proved that the final settlement amount will be consistent after a long time, but the actual settlement amount will always be smaller than the predicted settlement amount during the settlement progress stage. The consolidation factors estimated by the curve fitting with the condition that the secondary compression begins in the second half of the primary compression showed similar values to the consolidation factors estimated by the curve fitting for the primary compression only, and the settlement curves were in better agreement throughout the compression. It showed different values, showing low validity. It can be inferred that secondary compression acts from the point when a significant portion of the excess pore water pressure is dissipated, and the loading stress begins to have more influence on the skeletal structure of the soil. Analysis results show that secondary compression begins at the range of 91 % to 98 % on the average degree of primary consolidation.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.69-75
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• 2013

Suction stress is evaluated from soil water retention curves in order to deduce effective stress in unsaturated soils. $K_0$ consolidated triaxial tests were performed for silty sand to interpret effective stress in consolidation and shearing of unsaturated soils. Suction stresses from both consolidation stress and shear strength in triaxial tests were compared with those from soil water retention curves. The effective stresses on consolidation and shear strength are on each unique line, which are the same as that of the saturated case. It was found that the effective stress from soil water retention curves agrees with those from consolidation and shear strength in triaxial tests.