• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.469-476
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• 2002

There are many methods to accelerate for consolidation of the soft ground but, in this study, only preloading method was used to improve the soft ground. To measure the settlement of soft ground, surface-settlement plates were installed at several points. To examine settlement behavior of soft ground, back analysis was done using the measured results. In the back analysis, consolidation parameter( $c_{v}$) were obtained and it was compared with test result for undisturbed sample.e.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.313-316
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• 2002

This study was performed to evaluation the consolidation behavior of agricultural reservoir in the very soft ground. The final settlement prediction methods by Hyperbolic and Asaoka methods were used to compare with the degree of consolidation estimated by exess pore water pressure. The dissipated excess pore water pressure during embankment construction and peak excess pore water pressure on the completed embankment were suggested for the estimation of the degree of consolidation. It was concluded that the degree of consolidation estimated from dissipated excess pore water pressure was more reliable than that from the peak excess pore water pressure.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.641-648
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• 2000

The horizontal drain method by installing drains horizontally in the ground is often used to expedite the dispersion of pore water and to increase the strength of dredged soft clay under the action of gravity or vacuum. In this study a numerical analysis method is developed to predict the consolidation process of soft ground with horizontal drains. One-dimensional self-weight consolidation theory is extended tn three-dimensions] theory with appropriate boundary conditions of horizontal drains. In the condition of pore water drainage by gravity, the behavior of the dredged clay with horizontal drains is compared with that of the clay without drains. The influence of design factors of drains on consolidation process is also analyzed.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.83-89
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• 2004

The analysis about consolidation characteristic in soft clay has been depending one-dimension consolidation analysis. but, drain and undrain zone are explicated as homogeneous by consolidation behavior following consoli- dated settlementsoft in soft clay. 1) Established sand drain in soft clay in many types, and measured water content, unconfined compression strength, vertical stress, horizontal stress, vertical settlement, pore water pressure. 2) Arranged the result from the test and numerically explicated effective stress, total stress, and effective stress path at the drain and undrain zone. 3) We also analyzed and comparied elastic and elastic-plastic in soft clay using measured data. The result analyzed does not approach to a special theory, but, it is well in accord with the result of other investigator's study in the same condition.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.45-57
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• 2017

Temperature change affects consolidation behavior of soft clays. The increase of temperature in soft clays induces the increase of pore water pressure. The dissipation of the excess pore water pressure decreases volume and void ratio. Also, the consolidation rate is accelerated by high temperature which induces the decrease of viscosity of pore fluid. The effects of temperature on the consolidation behavior such as consolidation settlement, consolidation time, and pore water pressure were investigated in this study. A numerical analysis of hydro-mechanical (HM) and thermo-hydro-mechanical (THM) behavior was performed. The combination of heat injection and sand drain for consolidating the soft ground, with varying temperature (40 and $60^{\circ}C$) and sand drain diameter (40, 60, and 80 mm), was considered. The results show that the temperature inside soil specimen increases with the increase of the temperature of heating source and the diameter of sand drain. Moreover, the heat injection increases the excess pore water pressure and, accordingly, induces additional settlement in overconsolidated (OC) state and reduces the consolidation time in normally consolidated (NC) state.

• 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.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.67-74
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• 1999

Self-Boring Pressuremeter Test(SBPT) is known to be the most effective in-situ test method which can reliably determine consolidation characteristics as well as deformation modules and untrained shear strength. In order to derive the coefficient of consolidation using SBPT results it is necessary to obtain the dissipation behavior from the pore pressure change with time during constant radial strain(generally 10%) and to derive the reliable time factor(Τ) from the analytical method which considers the real in-situ conditions. As previous studies on time factor are based on the assumptions of plane strain condition that the membrane of SBP is infinite, of untrained condition during the expansion of the probe and of elastic soil behavior during consolidation, these analyses can't consider the real boundary conditions and the real soil behaviour. In this study, consolidation analysis similar to real in-situ conditions including test procedure is conducted using finite element program which employs MCC model and Biot theory. Time factor considering the effects of finite membrane length, the total pressure change during consolidation and partial drainage is proposed and compared with previous results.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.376-381
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• 1998

The large scaled field test by prefabricated vertical drains was performed to evaluate the superiority of vertical discharge capacity for drain materials through compare and analyze the time-settlement behavior with drain spacing and the compression index and consolidation coefficient obtained by laboratory experiments and field monitoring system 1. The relation of measurement settlement( $S_{m}$) versus design settlement( $S_{t}$) and measurement consolidation ratio( $U_{m}$) versus design consolidation ratio( $U_{t}$) were shown $S_{m}$=(1.0~l.1) $S_{t}$, $U_{m}$=(1.13~l.17) $U_{t}$, at 1.0m drain spacing and $S_{m}$=(0.7~0.8) $S_{t}$, $U_{m}$=(0.92~0.99) $U_{t}$ at 1.5m drain spacing, respectively. 2. The relation of field compression index( $C_{cfield}$) and virgin compression index( $V_{cclab}$) was shown $C_{cfield}$=(1.0~1.2) $V_{cclab}$, But it was nearly same value when considered the error with determination method of virgin compression index and prediction method of total settlement. 3. field consolidation coefficient was larger than laboratory consolidation coefficient, and the consolidation coefficient ratio( $C_{h}$/ $C_{v}$) were $C_{h}$=(2.4 ~ 3.0) $C_{v}$. $C_{h}$=(3.5 ~ 4.3) $C_{v}$ at 1.0m and 1.5m drain spacing and increased with increasing of drain spacingngasing of drain spacingng spacingng

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1-6
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• 2008

When a saturated clay is sampled in an undisturbed manner from a bore hole, the sample extends vertically and shrinks horizontally under undrained conditions due to stress release. The conventional consolidation test specimen is trimmed from the expanded sample so that its diameter is equal to the inner diameter of the consolidation test ring, this test procedure does not reproduce the actual consolidation behavior. The measurement of sample extension was conducted by means of overcoring method found that the extension strains were 1 to 2%. To simulate the in-situ consolidation behavior, the consolidation test method that uses a specimen with a slightly smaller diameter than the inside diameter of consolidometer so that the specimen expands laterally to the inside of the ring.

• Journal of the Korean Geosynthetics Society
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• v.4 no.4
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• pp.39-46
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• 2005

A series of numerical analyses on soft clay ground improved by plastic board drain(PBD) were carried out, in order to investigate the consolidation behavior considering viscosity of the improved ground. The applicability of numerical analyses, in which an elasto-viscoplastic three-dimensional consolidation finite element method is applied in this study, was confirmed through comparison between experimental and analytical results. As the analytical results, consolidation behavior of both settlement and excess pore pressure and effective stress in clay were elucidated. Then secondary consolidation characteristics of improved ground were estimated through compare with results of typical one-dimensional consolidation analysis.