• Journal of the Korean GEO-environmental Society
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• v.17 no.3
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• pp.5-12
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• 2016

Stone column is the method that replace soft ground such as weak clay and loose sand with gravel or crushed stone which has relatively high stiffness and low compressive. Stone column increases bearing capacity of the soft ground, reduces settlement, produces ground improvement effect by consolidation drain, and is effective to prevent soil liquefaction in sandy ground during an earthquake. Stone column has been used in many civil works, and has recorded quite a lot of construction achievement internationally, but there is no standardized settlement calculation method yet. Therefore, in this study, the applicability of the existing theoretical equations were evaluated through comparison and analysis to predict a reasonable settlement of the Stone column. Consequently, Hook's law formula was verified to be the most close to numerical analysis.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.248-256
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• 2017

Groundwater drawdown was pointed out as one of the causes of induced settlement on high speed railways, especially concrete track. In this study, the effect of groundwater variation on settlement was evaluated through a comparison of field measurements with numerical analysis results. A trial and error method, i.e., repeated numerical analyses by changing material properties, was used to calibrate the model. The model was applied to investigate the effect of groundwater drawdown, thickness of soft layer, and embankment height on residual settlement after concrete track completion. A soft layer thicker than 4m would result in more than 30mm of settlement; a detailed analysis of groundwater behavior thus should be conducted from the design stage to construction.

• Journal of the Korean GEO-environmental Society
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• v.14 no.9
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• pp.57-65
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• 2013

Carbonate sands can be crushed under low confining pressure to achieve high compressibility. So particle crushing has significant influence on characteristics of strength and deformation. Trial embankment and hydrotest are conducted on Sabkha layer, consisting of carbonate sand to build tank structure. In this paper the settlement behavior was analyzed from each test. Particle crushing happened from 80 to 170kPa stress under compression test, and calcium was detected from chemical test. The test result came out Sabkha soil was very weak and easy to be crushing. About trial embankment test, particle crushing was not happen, and then extinction of pore water pressure and settlements were finished just during 2 days. On the other hand, the long-term settlement was happened in hydrotest. So the two test results did not correspond to each other. If loading stress is higher than yielding stress, instant settlement and secondary compression settlement are happened as a result of the particle crushing.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.159-162
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• 2003

In this study, it was proposed that a modified equation for estimating consolidation settlement on soft clay ground, which separate total settlement into primary and secondary settlement equation. The settlement by the proposed equation and by the measured settlements from laboratory model test was compared and verified for its application. It was appeared that the proposed equation from the laboratory model test approached 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 measure the initial period of settlement but the proposed equation could be much applicable in the lacking condition of measured data of the initial period.

• Journal of Ocean Engineering and Technology
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• v.14 no.3
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• pp.61-65
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• 2000

The estimation of soil stabilization is of great importance concerning the construction of structures on weak soil. A typical model of soil stabilization is considered as replacement, which is based on ground at failure due to direct loading on weak soil. The calculation of the line of predicting settlement was carried out using RPL and DIKE programs. The DIKE program is showing a tendency to excel totally about this embankment of the seadike. Hereafter, This program will be contributed widely to the construction of offshore structures on weak soil.

• 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.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.442-446
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• 2003

연약지반으로 분류되는 조간대 퇴적층의 연구는 제한적인 시추자료에 의존하고 있다. 비파괴 지반조사 방법은 시추자료에서 획득할 수 없는 지층의 측방변화와 지질 이상대를 확인할 수 있는 대안이 될 수 있다. 지구물리탐사 방법은 현장 토질조사와 같이 직접적인 지반조사 방법과 병행할 경우 지반을 이해하는데 있어 한층 나은 결과를 얻을 수 있다. 부산신항 배후부지 조성지역에서 매질의 상이한 특성에 기초한 비파괴 지반조사 방법으로 이용되는 지구물리탐사를 실시하였다. 각 탐사의 결과는 서로 유사한 지층경계를 나타내며, 시추와 매립공사의 결과와도 일치한다. 또한 계측을 위해 매설된 침하판이나 매설관로의 탐지, 압밀차이에 의한 부등 침하의 측방변화 등과 같이 시추조사에서 인지하기 어려운 부분에 대한 정보를 제공하고 있다.

• 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.

• Korean Journal of Agricultural Science
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• v.25 no.2
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• pp.225-234
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• 1998

This study was compared the degree of consolidation by Hyperbolic, Curve fitting, Asaoka's, Monden's methods using measured value with theoretical curve in consideration of smear effect and well resistance. The results of the study were summarized as follows ; 1. The degree of consolidation by Hyperbolic method was underestimated than the degree of consolidation by Curve fitting, Asaoka's, and Monden's methods. 2. Typical range of horizontal coefficient of consolidation was $C_h=(2{\sim}3)C_v$ in the case considering smear effect and well resistance, and $C_h=(0.5{\sim}2.5)C_v$ in the case disregarding smear effect and well resistance. 3. The degree of consolidation obtained by ground settlement monitoring was nearly same value when the coefficient of permeability of smear zone by back analysis was shown the half that of in-situ and the diameter of smear zone was shown double that of mendrel. 4. Increasing of diameter reduction ratio of drain, the time of consoildation was delayed. The affection of well resistance the case of small coefficient of permeability was much more than that in the case of large coefficient of permeability. It was recommended that design of diameter reduction of drain consider smear effect and well resistance.

• Journal of the Korean Geotechnical Society
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• v.27 no.11
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• pp.5-15
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• 2011

This paper presents two analysis methods for characterizing the non-linear finite strain consolidation behavior of highly deformable dredged soil deposits along with the fundamental parameters obtained in the companion paper; that is, the zero effective stress void ratio, the non-linear relationships of void ratio-effective stress and void ratio-hydraulic conductivity. The simplified Morris's analytical solution (2002) and the widely recognized numerical program, PSDDF (primary Consolidation, Secondary Compression, and Desiccation of Dredged Fill) for both single and double drainage conditions are adopted in this paper to verify a series of laboratory experiments for self-weight consolidation of the Incheon clay and Kaolinite. The comparisons show that the analysis methods proposed herein can properly simulate the long-term non-linear finite strain consolidation behavior for dredged soils in the field. In addition, a case study for the artificial Craney Island has been conducted to illustrate the importance of obtaining appropriate non-linear finite strain consolidation parameters and the applicability of PSDDF in promoting dredged soil disposal.