• Journal of the Korean GEO-environmental Society
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• v.18 no.2
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• pp.59-65
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• 2017

The costal reclamation construction is for making reclaimed land by dredging marine clay with seawater, and then bringing the dredged soil into the reclaimed land. During the process, the dredged soil in the reclaimed land undergoes the sedimentation-consolidation process. Among the processes, the consolidation is a very critical factor when planning reclaimed land because of its requiring time and settlement. In order to predict the requiring time and settlement, the Column test, which was suggested by Yano, has been usually used in the nation. However, the test method needs a very long time to identify the characteristic of sedimentation-consolidation of dredged soil. Therefore, in this study, in order to supplement the weakness of the Column test which needs such a long time, and in order to identify the characteristic of the sedimentation-consolidation for dredged soil in a short time, the Geo-centrifuge test was examined as an alternative method. The result considered that Geo-centrifuge test would be useful to identify the characteristic of sedimentation-consolidation for dredged soil efficiently.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1190-1197
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• 2009

Design parameters related to Yano's method(1984, 1985), one of experimental approaches having been used widely in Korea to estimate sedimentation and consolidation of dredged and reclaimed ground, were analyzed and their propriety were reassessed in this paper. Data analyses were performed on the basis of the settling test results using samples from the west coastal area of Korea. From analysis of results, for specific characteristics of these dredged and reclaimed marine soft clays, co-relations of initial water content - coefficient of sedimentation/ consolidation - initial setting velocity were evaluated. Relation between height of soil solid and surface height of slurry at the stages of initiation and termination of consolidation was also assessed. Finally ranges and average values of these design parameters were evaluated and typical empirical equations between these design parameters were also proposed.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.101-111
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• 2000

This research is results of experimental and numerical works on characteristic of strength increase and bearing capacity in dredged and reclaimed soil due to desiccation shrinkage. For a soil sampled from southern coastal area in Korea, basic soil property tests and standard consolidation test with falling head permeability tests were carried out to obtain consolidational characteristics of soil. Double cone penetration test, laboratory vane test and unconfined compression test were also performed to investigate the change of shear strength with degree of desiccation. Model tests were performed in 1G environment and 30G level artificially accelerated condition by using the centrifuge model test facilities to investigate the bearing capacity of desiccated ground. Test results were analyzed by using the theoretical and load-settlement characteristics method proposed by Meyehof & Hanna(1978). On the other hands, the numerical technique, using the finite strain consolidation theory considering the effect of desiccation was used to estimate the appropriate time of using heavy construction equipments in field with respect to strength increase due to desiccation.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.185-192
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• 2000

Recently, the hydraulic fill method is commonly used in many reclamation projects due to lack of fill materials. The method of hydraulic fill in reclamation is executed by transporting the mixture of water-soil particles into a reclaimed land through dredging pipes, then the dredged soil particles settle down in the water or flow over an out flow weir with the water. In the present study, practice each three method in order to suggest method of determining the loss rate of the dredged fills. The first sieve and hydrometer analysis were performed with the soil samples obtained before and after dredging and then apply theory of particle breakage, the second compare with the volume of dredged soil between at the dredging area and the target pond and the last compare with weight of dredged soil between before and after dredging at the dredging area and in the target pond for estimating the amount of soil particles residual at the reclaimed area and the loss of soil particles passed through the weir. In addition to compare with the loss ratio between as using Marsal's modified theory of particle breakage and measured weight and volume in the field.

• Journal of Industrial Technology
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• v.34
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• pp.53-59
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• 2014

The single regression method was used to analyze the correlationship between the compression index with mechanical properties for reclaimed marine clays in the southern coast of Korea. As results of performing regression analysis for 200 samples about reclaimed marine clays in the southern coast of Korea, linear regression lines between compression index and natural water content, void ratio in situ, and liquid limit respectively wer obtained. The changed properties of soil due to disturbance during dredging and reclaiming could be investigated by comparing with the existing empirical correlation equations for the original ground where dredging was performed. These regression equations might be rationally used in the preliminary evaluation of settlement of dredged and reclaimed marine clayey ground in the southern coast of Korea.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.606-611
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• 1999

Recently , the hydraulic fill method is commonly used in many reclamation projects due to lack of fill materialss. The method of hydraulic fill i recalmation is executed by transporting the mixture of water -soil particles into a relcaimed land through dredging pipes, then the dredged soil particels settle down in thewater orflow over an out flow weir with the water. The amount of the volume reductions of dredged soil is considered the sum of the overall settlement by descication shrinkage and self-weigth consolidation and the loss of soil particles flow over a weir. In the present study, hydrometer analysis was performed with the soil samples obtained bofore and after dredging to estimate the amount of soil particles residual at reclaimed area and the loss of soil particles , then it was suggested the method of determining the loss ratio of dredged soils from the tests results. The hydrometer analysis of in-situ soil samples showed that the loss ratio of dredged soils is lowest at the nearest point to dredge pipe and highest at the nearest point of out flow weir.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.97-104
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• 2015

When carrying out design for soft ground improvement before reclamation of dredged soil, it is very important to appropriately evaluate design parameters such as compression index and undrained strength in order to estimate optimum construction cost. In this study, consolidation and strength parameters were estimated by the samples obtained from the similar reclaimed land. Water content and compression index of dredged soil reclaimed by hydraulic fill method were quite decreased in comparison with those of in-situ conditions at Incheon site. Relationships between compression index(Cc) and water content (wn), and between undrained strength (su) and water content (wn) for dredged soil were obtained by field vane test and oedometer test, respectively. Applicability of Schmertmann correction method (compression index) for low plasticity silty soil was discussed according to comparison with designed and measured settlements.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1717-1726
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• 2008

Vibration triaxial compression test was put in influence for liquefaction strength of fine grained soil of dredged and reclaimed ground and consideration for fine fraction content, relative density, overconsolidation ratio and plasticity index in this study. By the results of these test, the liquefaction strength increased with fine fraction content and the relative density, overconsolidation ratio incresed with liquefaction strength too. However, in the case of nonplastic silt was the smalist liquefaction strength which influenced by dilatancy and interlocking when silt content was 34.7%(average grading 0.12mm). Therefore, liquefaction strength of fine grained soil of dredged and reclaimed ground increased with fine fraction content so it will help to make lower liquefaction.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.317-327
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• 2001

For soils with high void ratios, the inverse method of utilizing results obtained from centrifuge model test was used to find the constitutive relation of effective stress - void ratio - permeability whereas conventional oedometer test and constant rate of strain consolidation test were also used to fine its relation at ranges of relatively low void ratio. Results of column test about settlement of interface and pore pressure and distribution with time were compared with numerically estimated values to confirm such a constitutive relation as obtained from the inverse method. Consolidational settlement in dredged and reclaimed ground, where the consolidation was in progress, was predicted by using the numerical technique implemented with the finite strain consolidation theory.

• 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