• Computational Structural Engineering
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• v.10 no.4
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• pp.327-336
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• 1997

When a structure is built on the consolidation ground, the instant elastic deflection occures according to the characteristics of the ground and the load on it. And the corresponding contact pressure is established. But, as time passes, the secondary consolidating deflection is added to the instant elastic deflection, the upper structure, due to its flexural rigidity, resist to the additional curvature. So the variation of the contact pressure occurs. And this new contact pressure exerts influence on the consolidation form again. The new consolidation form exerts influence on the contact pressure in return. This kind of interaction continues till all the consolidation of the ground is finished. So the consolidation problem can not be definded as the linear problem. This paper intends to scheme an approximate iteration method to analyse this non-linear interaction problem between the upper structure and the lower consolidation ground which supports the former.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.399-403
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• 2003

해안의 연약지반에 건설되는 폐기물 매립지는 매립지의 안정성 평가를 위하여 하부기초지반의 침하거동 특성에 대한 분석이 필요하다. 본 연구에서는 현장 침하계측자료를 이용하여 현장 간극비와 현장 압축지수를 역산하여 그 특성을 분석하였다. 그 결과 매립초기에는 상부하중에 의한 유효응력증가가 미소하여 하부기초지반은 과압밀 특성을 나타내고 현장 압축지수 변화가 미소하였으나, 매립이 진행될수록 상부하중이 선행압밀하중을 초과하여 정규압밀영역으로 변화함에 따라 큰 폭의 증가를 보였다.

• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.35-42
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• 2012

There are many large-scale coastal region landfill and land development by loading to use territory efficiently, this regions are mostly soft clay ground. Constructing structures and road on the soft ground bring about engineering problems like ground shear fracture and a big amount of consolidation by bearing capacity. Improvement of soft soil is required to secure soil strength and settlement control. In improvement of soft soil, predict for the amount of settlement based on field surveyed reports are important element for estimating pre-loading banking height and the final point of consolidation. In this study, there is calculating theoretical settlement by analyzing field surveyed report and ground investigation to improvement of soft soil with pre-loading and vertical drain method. And present settlement prediction method reflect soil characteristics in Gimpo Hangang site by analysing prediction settlement and observational settlement during compaction using hyperbolic, ${\sqrt{s}}$, Asaoka method.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.7-14
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• 2001

구조물 하중에 의한 점성토 지반의 침하량을 보다 정확하게 평가하기 위해서는 지반 내의 흙요소가 경험하는 실제적인 응력경로와 이에 따른 변형양상이 적절하게 고려되어야만 한다. 따라서 본 연구에서는 축대칭 조건의 다양한 응력경로를 따라 발생하는 정규압밀 점성토의 변형 거동을 고찰한 기존의 실험적 연구결과를 바탕으로 응력경로법에 근거한 보다 간편하고 합리적인 침하량 평가기법을 제시하였다. 또한 본 연구에서는 제시된 평가기법을 기존의 1차원적인 침하량 평가기법들과 함께 실제와 유사한 조건을 가지는 가상지반의 침하량 산정에 적용해 보았으며, 동일한 조건에 대해 소성모델(MCC 모델)과 혼합압밀이론에 바탕을 둔 유한요소해석을 실시하였다. 그리고 이를 통해 얻어진 결과들을 비교.분석함으로써 기존 평가기법들의 문제점과 한계를 명확히 제시하였으며, 응력증분 평가방법이 침하량 평가에 미치는 영향을 분석하였다.

• Geotechnical Engineering
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• v.11 no.4
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• pp.13-24
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• 1995

Laboratory testings, consisting of soil properties testing and vacuum consolidation testing with and without vertical wick drain, were carried out on five different types of soil to determine soil properties and relationship between settlement and time. One dimensional consolidation teat was performed to determine if this test could be used for predicting the behavior of soils during vacuum consolidation. From the results of this study, the one dimensional consolidation test does not appear to be suitable for predicting the rate of vacuum consolidation without wick drain. However, one dimensional consolidation test reasonably predicts the total settlement of vacuum consolidation without wick drain. In vacuum consolidation, the amount of the settlement for silty soils were more or less the same for both cases, with wick drain and without wick drain, even if the time required for consolidation was considerably different. And, strategic placement of wick drain ensures moisture content and the value of the density are similar throughout the soil sample. However, the presence of wick drain for clay Boils increased the amount of settlement and also shortened the time required for consolidation.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5C
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• pp.201-208
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• 2010

In this study, the ground settlement was investigated by using monitoring data of the test sites where vacuum consolidation method and surcharge method were applied for improving deep soft soil. The monitoring data are chosen in ${\bigcirc}{\bigcirc}$ area port construction site reclaimed with very soft dredged clay. These data are analyzed to compare the consolidation characteristics between the different loading methods for soil improvement. Through analysis of the loading time, it is shown that the ground settlement reaches its allowable value under vacuum consolidation loading by about 45% faster than that of the surcharge loading consolidation. This could be explained that vacuum consolidation method makes the isotropic consolidation condition so that the time for reaching a certain final preloading without soil failure can be shortened.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.85-95
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• 2007

In this study, in order to propose the prediction method of the residual settlement of clayey ground improved by vertical drains, a series of numerical analyses for a model ground were carried out using the elasto-viscous consolidation model. And the effects of ground improvement conditions of the ratio of effective radii $(r_e/r_w)$, consolidation pressure $({\Delta}p)$ on normally consolidated state, and the OCR (overconsolidation ratio) on overconsolidated state to reduce the residual settlement in three-dimensional consolidation by vertical drains were investigated by performing a series of numerical analyses. Furthermore, based on the results of a series of numerical analyses for the model ground, the predicting method of the residual settlement of clayey ground with vertical drains and the determination method of the value of OCR required to control the residual settlement within an acceptable value are proposed.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.513-523
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• 2022

The purpose of settlement management when treating soft ground through preloading is to determine the amount of settlement, check the progression of consolidation, and compare the settlement with the target settlement amount. Of the various methods available for predicting settlement based on measured data, the hyperbolic method was used in this study to analyze the settlement behavior of soft ground considering the creep behavior resulting from staged fill. Two versions of the method were used: the existing hyperbolic method, and a modified hyperbolic method. The existing hyperbolic method predicts the settlement amount using data for the final settlement section only during soft ground treatment through staged fill, for which the coefficient of consolidation behavior (k) was computed to give a predicted final consolidation settlement amount of S_r = 1.05 cm. In comparison, using the modified method, a predicted final consolidation settlement of S_r = 0.50 cm is obtained by considering the data for each staged fill section. These results show that the modified method considering data from the staged settlement was more accurate than the existing method considering data only from the final settlement section. This modification to the hyperbolic method therefore represents an improvement in performance over the existing method.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.87-96
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• 2014

In this paper, reliability analysis was done on the characteristics of consolidation and settlement for the inner temporary dike where a weak ground improvement construction was applied. When the consolidation analysis on the foundation ground was done, the following conclusions were obtained by conducting the stability analysis on the effect of space of drains, the effect of consolidation time, and the residual settlement and differential settlement. When construction was done with a drain space which satisfied 95% probability of reaching a target consolidation in each divided area, the occurrence of a residual settlement was within the range, which did not exceed 10cm. It was shown that there was almost no possibility of the occurrence of differential settlement, which was above the permissible differential settlement slope.