• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.3
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• pp.39-47
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• 1985

In this paper, a FEM analysis model was developed to solve the consolidation phenomena of embankment on the soft foundation. The developed FEM model was based on the Biot's consolidation equation which was coupled with one of three stress-strain constitutive relationships. In order to check the validity of the newly developed FEM model, the program input data were used by a test embankment which had been already constructed at Cubzac-les-ponts in France by Magnan et al. The FEM results compared to the experimental and analytical results which were obtained by the Magnan's group at Cubzac-les-ponts. The results compared showed that the consolidation phenomena were well explained by the author's FEM model which results were more accurate than the others. As for the pore water pressure, Christian-Boehmer's method used in this paper was considered preferable to Sandhu-Wilson's used by Magnan.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.113-120
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• 2007

For the cases of constructing reinforced earth and gabion walls on the soft ground, an appropriate replacement area of soft ground required to maintain the stability of walls was investigated by FEM analyses. Incremental analyses were performed in FEM, in which construction sequences including consolidation of soft soil layer were simulated. As a first step to suggest the appropriate replacement area, a series of analyses for cases varying the replacement depth were conducted to examine the behaviors of wall and adjacent ground according to the construction sequence. The analysis results were, then, evaluated with the proper limiting values of displacements of wall, settlements and shear strains of ground to guarantee the stability of walls, which were specified based on the literature review. Consequently, the typical construction drawings could be suggested, in which appropriate replacement areas for varying wall heights for the ground condition investigated in this study were represented in terms of the ratio of replacement depth to the height of wall.

• Tunnel and Underground Space
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• v.15 no.3 s.56
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• pp.195-212
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• 2005

Surface subsidence which occurs with several reasons, such as collapse of gangway, discharge of groundwater, compaction of weak rock mass, and tunnel excavation in shallow depth, gives rise to a serious problem in national infra-structures. In this study, therefore, the mechanism of subsidence has been examined numerically to overcome the passive approach on subsidence occurrence area. With many kinds of numerical studies, the major geotechnical parameters have been selected and the weighted values have been defined for each parameters. Also the authors developed the numerical program which can estimate the possibility of subsidence occurrence, and proposed the decision method for objective and quantitative guideline. It is anticipated that this research will be helpful to establish the hazard map on subsidence region.

• Journal of the Korean Geotechnical Society
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• v.23 no.1
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• pp.67-76
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• 2007

Flat DMT penetration was analyzed using a finite element model based on a large strain formulation. The ABAQUS/Explicit, a commercial finite element method, was used to study the flat DMT penetration in soils. Then, because the very large mesh distortion occurred due to the penetration of flat DMT, the adaptive meshing technique was utilized to maintain a high quality mesh configuration. The undrained shear strength obtained from the flat DMT is estimated using only the horizontal stress index ($K_{D}$) and so it became necessary to examine using the analysis results obtained from the penetration of the flat DMT. Analysis results show that in normally consolidated region of $K_{D}=2$, the results obtained from the correlations proposed by Marchetti show good agreement with those estimated from the finite element method. The present analysis also shows that in overconsolidated region of $K_{D}>2$, the results obtained from the relationships proposed by Kamei and Iwasaki show good agreement with those provided by the penetration analysis.

• Journal of the Korean Geotechnical Society
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• v.26 no.1
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• pp.35-43
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• 2010

The behavior of the Top-Base foundation was investigated by carrying out 3D finite element method. Special attention is given to the settlement behavior of concrete Top-Base foundation due to the consolidation settlement of the embedding depth and the effect of footing dimensions which are not included in the practical design. To obtain the detailed informations, a series of numerical analyses were performed for different pile configurations. It is shown that as the number of piles in a group increases, the calculated settlement also increases. However, for the $7\times7$ group, there is no further increase in settlement. Based on this study, it is found that the total settlement of Top-Base foundation is highly influenced by the consolidation settlement and footing configurations. It is also found that the current design method overestimates the settlement, and thus, needs to be modified and supplemented.

• Journal of the Korean Geotechnical Society
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• v.26 no.11
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• pp.47-61
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• 2010

To predict the settlement rate of a ground area that incorporates vertical drains, it is desirable to conduct various kinds of advanced field and laboratory tests for hydraulic properties. However, it is urgently needed to appropriately evaluate the hydraulic properties using the results of conventional soil tests which are extensively used for local practice. To achieve this purpose, a number of CPT dissipation test, laboratory permeability and consolidation tests were performed at five sites in the floodplain of the Nakdong River delta, and the test data were comprehensively analyzed. As a result, it is found that the coefficients of horizontal consolidation ($C_{h,NC}$) and permeability ($k_{h,OC}$) of the clay agreed well with those of the CPT-based methods proposed by Baligh and Levadoux (1986). The values of $C_{h,NC}$ and $k_{h,OC}$ were in the range of $0.4{\sim}3.0\;cm^2/sec$ and $0.40{\sim}2.50\;cm^2/sec$, each of which slightly increases or decreases with depth, respectively. It was also inferred that these trends seem to reflect the depositional environments of the clay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1359-1369
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• 2012

In the case of using pile foundation to support bridge abutments on soft ground, the soft ground often causes serious troubles such as lateral movement of bridge abutments by lateral surcharges. In this paper, we investigated and measured the amount of strain of a bridge abutment in the south-western part of Korea. To check the stability and possibility of lateral movement of the bridge abutment, we used the four analysis methods and compared those results; lateral movement index, index for decision of lateral movement and infinite element analysis method. We performed soil and ground tests to fine the causes of the strain and lateral movement. After reviwing several types of repair methods, we suggested the anker reinforcement method along with surcharge process method as a proper repair and rehabilitation of the bridge abutment. Our investigation by through the infinite element analysis method confirmed the effectiveness of the anker reinforcement method allong with the surcharge process method.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.45-49
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• 2003

Tensile strength of the woven glass fiber reinforced PET (Poly-Ethylene-Terephthalate) matrix composite manufactured by rapid press consolidation technique was investigated and evaluated. During pre-heating, consolidation and solidification stages, the optimal manufacturing conditions for this composite were discussed based on the void content and tensile properties depending on vacuum condition. It is found that the effect of vacuum condition during preheating gives a substantial difference on the strength as well as microstructure. It is also found that the failure micromechanism shows several energy absorption processes enhancing fracture toughness.

• 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 Ocean Engineering and Technology
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• v.5 no.1
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• pp.35-44
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• 1991

This study was carried out for the purpose of pre-estimating long-term settlement under condition of actual field soil's property, in case of building up industrial sites on the marine deposit silty clay located at West Coast in Korea. This study analyzed Hyperbolic Method, Square Root Time Method and Exponential Function Method with utilization of measured survey values of settlement in In-Cheon Namdong Industrial Sites. In the future, for the continuos utilization, it seemed to be needed that further the survey values of fields should be accurartely measured for the analysis of more accurate pre-estimate about long-term settlement. Among the prediction methods of settlement Hyperbolic Method seemed to be the best fitting method for measured data. The settlement equations were derived from above three methods, for long-term settlements.