• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.1
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• pp.101-107
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• 2014

It has been known that Terzaghi's consolidation theory is not well consistent with the consolidation phenomenon on the soft clay ground, but this theory has still been adopted normally in practice because there is no method for estimating the consolidation settlement and rate easier than Terzaghi's theory. It is impossible to map whole part of consolidation settlement vs time curve to the curve of Terzaghi'z average degree of consolidation. If the primary consolidation and the secondary compression are happened same time, it would be useless of trying to find the end of primary consolidation, but it is needed for using Terzaghi's theory that the end of consolidation is determined to the time of beginning consistency between the final settlement analyzed with curve fitting and the experimented consolidation settlement.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.93-100
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• 2000

This research is to investigate the self-weight consolidation settlement and desiccation shrinkage settlement of soft marine dredging clay by performing numerical and experimental works. Large column test were carried out investigate the consolidation settlement considering effect of the self-weight and desiccation shrinkage, and centrifuge model test was also carried out investigate self-weight consolidation settlement. Results of centrifuge model and large column experiments about changes of settlement with time were analyzed by using the numerical technique of explicit finite difference method considering effect of the self-weight and desiccation based on the finite strain consolidation theory. Centrifuge model test results were in relatively good agreements with analyzed results in terms of self-weight consolidation settlement with time. Large column test results showed quite different values from the numerically estimated one, carried by experimental conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.02a
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• pp.78-83
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• 1999

The ultimate settlement of soft clay consists of three parts: $\circled1$ immediate settlement, S$\sub$d/; $\circled2$ Primary consolidation settlement, S$\sub$c/; $\circled3$ Secondary consolidation settlement, S$\sub$s/. In general, S$\sub$c/ can be accurately calculated by one-dimensional consolidation and S$\sub$s/ or S$\sub$d/ may be ignored. This paper focuses on a calculation method to estimate the immediate settlement induced by lateral deformation of subgrade, to which shear stress is applied by embankment on soft ground. Immediate settlement and consolidation settlement are discussed by comparing the field measurement of the Yangsan test embankment on treated soft foundation by vertical paper drains.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.6
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• pp.35-41
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• 1996

The theory of consolidation has been achieved remarkable development in terms of theory such as finite consolidation theory, two dimensional Rendulic consolidation theory. Though those theories are well defined, the analysis is by no means straightforward, because associated properties are very difficult to determine in the laboratory, Therefore Terzaghi's one dimensional consolidation theory and Barron's cylindrical consolidation theory are still widely used in engineering practice. The theoretical shortcomings of those consolidation theories and uncertainties of associated properties make inevitably some discrepancy between theoretical and field settlements. Field settlement measurement by settlement plate is, therefore, widely used to overcome the discrepancy. Ultimate settlement is one of the most important factor of embankment construction on soft soils. Nowadays the ultimate settlement prediction methods using field settlement data are widely accepted as a helpful tool for field settlement analysis of embankment construction on soft soils. Among the various methods of ultimate settlement prediction, hyperbolic method and Asaoka's method are most commonly used because of their simplicity and ability to give a reasonable estimate of consolidation settlement. In this paper, the reliability of hyperbolic method and Asaoka's method has been examined using analytical methods. It is shown that both hyperbolic method and Asaoka's method are significantly affected by the direction of drainage.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1712-1716
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• 2008

Performance of ground improvement project using prefabricated vertical drains of condition, in which approximately 10m dredged fill overlies original soft foundation layer in the coastal area has been conducted. From field monitoring results, excessive ground settlement compared to predicted settlement in design stage developed during the following one year. In order to predict the final consolidation behavior, recalculation of consolidation settlements and back analysis using observed settlements were conducted. Field monitoring results of surface settlements were evaluated, and then corrected because large shear deformation was occurred by construction events in the early stages of consolidation. To predict the consolidation behavior, material functions and in-situ conditions from laboratory consolidation test were re-analyzed. Using these results, height of additional embankment is estimated to satisfy residual settlement limit and maintain an adequate ground elevation. The recalculated time-settlement curve has been compared to field monitoring results after additional surcharge was applied.

• Journal of the Korean Geosynthetics Society
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• v.11 no.2
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• pp.49-54
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• 2012

The final consolidation settlement is important factor in soft ground improvement because of settlement management and completion time. The compression index, which is slope of primary consolidation curve, is commonly used for the calculation of final consolidation settlement in clay layer. The existing final consolidation settlement is calculated in total consolidation layer that is assumed as one layer. This paper describes analysis result of the acquired settlement, when the consolidation layer is divided as several layer. The consolidation settlement increased according to increase of the divided layer and then it is converged. This result was unrelated to surcharge load. The division effect of layer is very high when the surcharge load is less than the consolidation layer thickness. The division effect of layer is 1.2 to 1.4 in the general surcharge load, and this value can be apply as safety factor in the calculation of final consolidation settlement.

• Journal of Industrial Technology
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• v.31 no.B
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• pp.91-98
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• 2011

In this thesis, from the results of settlement measurement performed at the site where embankment earthwork was carried out on the ground consisting of highly plastic and silty soft soils interlayered with organic deposits, various methods of predicting the embankment settlement such as Hoshino's method, Asaoka's method, hyperbolic method, ${\sqrt{s}}$ method and Monden's method were used to investigate their applicability and the inverse method of finding the soil parameter related to consolidation was used to predict the consolidation behavior in the future. It was confirmed that reliable prediction of consolidation behavior under various conditions could be done to estimate soil parameter related to consolidation such as the consolidation index and consolidation coefficient by the inverse method of comparing the measured settlement with the predicted value by the settlement prediction methods.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.188-194
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• 2009

Consolidation settlement, a crucial parameter in geotechnical design of soft ground, has not been computed in a unique way due to different computation methods in practice. To improve computational error in calculating consolidation settlement, a number of researches has been attempted. Conventional 1-dimensional consolidation theory assumes the center of the clay layer as the representative point to obtain effective stress in calculation, which could resort to erroneous results. To calculate exact solutions considering initial distribution of effective stress, diving a stratum into multi-layers could resort to wasting time and effort. In the study, a novel methodology for calculating consolidation settlement via Guassian quadrature is developed. The method generally is capable of computing settlements in any case of the stress conditions encountered in fields.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.444-450
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• 2000

This study was performed to analyze the degree of consolidation by the dissipation of excessive pore water pressure and final settlement prediction methods of the very soft clay. Hyperbolic method, Asaoka method and curve fitting method were used to compute the degree of consolidation. The degree of consolidation with excessive pore water pressure were used to compute, which considered the dissipation time with embankment construction. The degree of consolidation that was obtained by the peak excessive pore water pressure was less than in the case of the dissipation excessive pore water pressure. And, the degree of consolidation by the total settlement was nearly the same value that of layer settlement. The degree of consolidation that was obtained by excessive pore water pressure was larger than in the case of the settlement.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.1
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• pp.61-68
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• 2005

In this study, it was proposed that an equation for predicting consolidation settlement on soft clay ground, which separate total settlement into primary and secondary consolidation settlement equation. The consolidation settlements by the proposed equation and by the measured settlements from laboratory model test were compared and verified for its application. It was appeared that the proposed equation from the laboratory model test approach to be more realistic comparing to !the result of Terzaghi's equation. From the above application, it was concluded that the final settlement prediction by. the Hyperbolic, Asaoka methods is needed to the initial settlement but the proposed equation could be much applicable in the lacking condition of measured data of the initial period.