• Proceedings of the Korean Geotechical Society Conference
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• 1999.11b
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• pp.51-81
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• 1999

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.69-77
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• 2007

In this study, the consolidation behavior of clayey ground improved by vertical drain method was analyzed by the finite difference method based on the three-dimensional elasto-viscous consolidation theory, which can express the behavior of the secondary consolidation without considering the distinction of the normally consolidated and overconsolidated states. And the applicability of the elasto-viscous consolidation theory was discussed by comparing with the test results obtained from the model test of ground improved by vertical drain system. From these results, it is found that the amount of the settlement when the excess pore water pressure almost dissipated in the clay ground with vertical drains became smaller than that of the one-dimensional condition, and then the amount and rate of the residual settlement at secondary consolidation process became larger than those of the one-dimensional condition. finally, the effect of soil parameter on behavior of consolidation process was investigated by the results of a series of numerical analysis for the normalized and overconsoldiated states.

• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.19-26
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• 2012

In this study, characteristics of consolidation settlement of soft grounds adapting preloading method and vertical drain method were compared. A real measurement settlement is compared with predicted one by the future settlement prediction method like the Asaoka's method, the Hyperbolic method and the Hoshino method. A accuracy of predicted future settlement by the Asaoka's method is relatively higher than the Hyperbolic method or the Hoshino method generally. But in the area conducted with the vertical drain method, settlement prediction accuracy of three methods is similar unlike popular beliefs; Asaoka's is the better method for prediction than others. The study area is also confirmed by investigation of the drainage system after applying the change through the N values, soil physical and mechanical properties were investigated, and physical properties are improved.

• Journal of the Korean Geotechnical Society
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• v.18 no.2
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• pp.107-121
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• 2002

In this study, GIS(Geographic Information System), a new approaching method, is proposed to effectively manage long-term settlements in the big reclamation sites. To verify an applicability of the proposed method, the prediction of long-term settlements which may occur in the overall soft deposits of the Incheon International Airport is carried out. During the process of the prediction of long-term settlements, measured settlement data obtained from an early stage of preloading are analyzed in detail. For purposes of the analysis, an estimation of the recompression index is also made based on the Nagaraj's research results. The coefficient of the secondary consolidation is further determined based on the relationship presented by the Mesri & Godlewski, which defines a ratio between the coefficient of the secondary consolidation and the recompression index.

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.35-42
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• 2000

The settlement characteristics of waste landfill site must be considered in the design of sanitary landfill as well as in the course of the rehabilitation of the landfill site. Among prediction methods for settlement of landfill site, especially Gibson and Lo model and Power Creep Law have been successfully applied to the landfill site where the amount of settlement was large and the secondary settlement was obvious. Therefore, the effects of organic content on the model parameter values utilized in both Gibson Lo model and Power Creep Law were studied by using a large consolidation testing apparatus. The organic content is each 20%, 40%, 60% of total volume and consolidation load is $0.1{\sim}1.6kg/cm^2$. The main results can be summarized as follows: (1) The reference compressibility of Power Creep Law is decreased according to the increments of consolidation load: (2) The field measurement is more similar to the Power Creep Law than the Gibson and Lo model.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.383-395
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• 2007

As a state-of-the-art paper related to consolidation settlement, the 31th Terzaghi lecture was briefly described. Case histories that are compared between predicted and measured settlements in the Nakdong River deltaic plane were introduced to show the true picture of our technology. Structures and other features of clays in this country were needed to understand, which are closely related to sample disturbance and also consolidation properties. In order to improve the settlement-related technology, some problems that we have faced and their alternatives were considered.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.99-110
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• 1999

Settlement and consolidation time were predicted through systematic soil investigation at the delta of Nakdong river where the preloading method was applied. Field measurements were executed with well-selected instruments. As the results of the comparison, the predicted settlement on the sand layer of about 20m thick underestimated the observed one by 20%. This underestimation was due to the effects of vibration during installation of PBD, creep, the overestimated deformation modulus, and so on. For the clay layer of about 20m in thickness under the sand layer, an ID analysis for underconsolidated soil initially overestimated the observed settlement by 240%. However, when the laboratory compression curve was reconstructed and a conventional ID analysis for NC clay was applied, the re-calculated settlement of the clay layer was relatively similar with the observed one. And the predicted consolidation time was about 45% less than the observed one, because of different influencing factors.

• Journal of the Korean Geosynthetics Society
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• v.18 no.3
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• pp.55-67
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• 2019

Deep soft ground in mouth of Nackdong river requires to be analysed with prediction method concerning characteristics of secondary consolidation from the beginning because it causes excessive settlement due to time-dependant secondary consolidation characteristics. This study investigated characteristics of extended settlement by conducting one-dimensional theory, elasto-plastic model and visco-elasto-plastic model as well as analyzing long-term measuring data observed over 2,000 days. According to one-dimensional theory and elasto-plastic model, there is not definite correlation between height of embankment and depth of soft ground while visco-elasto-plastic model showed similar result of settlement to that of long-term measuring data. Consequently it is suggested that applying visco-elasto-plastic model to developing deep underground place as studied area on predicting extended settlement before construction prevents economic loss and delay during process by preparing secondary consolidation characteristics.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.396-398
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• 2007

• Journal of the Society of Disaster Information
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• v.3 no.1
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• pp.37-53
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• 2007

Various difficult problems occur due to insufficient bearing capacity or excessive settlements when constructing roads or large complexes. Accurate predictions on the final settlement and consolidation time can help in choosing the ground improvement method and thus enables to save time and expense of the whole project. Asaoka's method is probably the most frequently used for settlement prediction which are based on Terzaghi's one dimensional consolidation theory. Empirical formulae such as Hyperbolic method and Hoshino's method are also often used. However, it is known that the settlement predicted by these methods do not match with the actual settlements. Furthermore these methods cannot be used at design stage when there is no measured data. To find an elaborate method in predicting settlement in embankments using various test results and actual settlement data from domestic sites, Back-Propagation Neural Network(BPNN) and Recurrent Neural Network(RNN) were employed and the most suitable model structures were obtained. Predicted settlement values by the developed models were compared with the measured values as well as numerical analysis results. Analysis of the results showed that RNN yielded more compatible predictions with actual data than BPNN and predictions using cone penetration resistance were closer to actual data than predictions using SPT results. Also, it was found that the developed method were very competitive with the numerical analysis considering the number of input data, complexity and effort in modelling. It is believed that RNN using cone penetration test results can make a highly efficient tool in predicting settlements if enough field data can be obtained.