• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.672-679
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• 2008

During recent years, the large soft ground improvements very rapidly increase with industrial development and it is the types and scales of structure that is enlarged by degree. Then, we must enter construct equipment to improve soft ground and we fulfilled works by carrying out soft clay soil to gain trafficability for them. For improving the soft ground, we lay geotextile on soft clay ground and fill the filter sand that can drain the pore water. Then, we landfill cover soil for come by trafficability of construction tools. Ater that we penetrate vertical drain for dehydration through soft ground. there are very complicated works. For these reason we suggest the methods of soft ground improvement constructions.

• Journal of the Korea Institute of Building Construction
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• v.1 no.1
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• pp.160-168
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• 2001

This study aims at the development of computer program for the deformation analysis of soft ground, and using this computer program, study the constraint effect of deformation heaving, lateral displacement of the soft ground reinforced with improvement of soft ground up to hard strata, under intact state(natural). The following results are obtained. 1. Improvement of soft ground to the hard strata works well against the settlement of neighboring ground. 2. the larger the rigidity or width of improvement of layer to hard strata is, the less settlement occurs. 3. Improvement of soft ground to the hard strata is of no use.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.553-560
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• 2002

The improvement effect of soft ground is estimated by unconfined strength mainly. The unconfined strength of solidification agent treated soil is likely to vary with ununiformed mixing ratio and water content change of in-situ ground place by place. So, it is unreasonable to apply a solidification agent mixing ratio obtained from laboratory test results on all over the soft ground. In this study, it was analysed how the unconfined strength would be effected by the water content of soft ground. For this study, a series of unconfined compressive tests are peformed on various water content soil samples. The test results showed that the strength was fallen to 30∼80% by two times increase of water content approximately, This means that strength of solidification agent treated soil is influenced greatly by water content of raw soft ground and mixing ratio of solidification agent. It was suggested that the method how to decide the mixing ratio with soft ground water content.

• Journal of the Korean Geosynthetics Society
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• v.19 no.3
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• pp.35-44
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• 2020

This study described the result of laboratory model tests, in order to compare the improvement effect of the DCM column installed on the soft ground according to DCM column type. In the laboratory model test, the non-reinforced type and the 3 types of DCM column were applied, and the behavior (settlement, lateral flow) of soft ground was evaluated under the surcharge load condition for each type. The settlement evaluation result showed that the settlement of soft ground without DCM column occurred rapidly under the low load condition, but the settlement of the soft ground with the DCM column had relatively small settlement. The evaluation result of lateral flow in the soft ground showed that the soft ground with DCM column had lower lateral displacement than the soft ground without DCM column. Especially, the lateral displacement under the same load condition decreased in the order of pile type, wall type, and grid type. Therefore, it confirmed that the improvement effect of soft ground was excellent when the DCM of grid type was applied for settlement and lateral flow.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.425-428
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• 2005

To resolve land demand by the development of various industries and the cityward tendency of population, the construction of ultra-soft ground that is unused in the past has been progressing with activity. The ultra-soft ground has very small shear strength and large deformation, so leads to many problems in ground improvement in construction. In order to dispose of these problems, it is necessary to develope the chemical materials that can be applied to the surface stabilization of ultra-soft ground. In this study, the new ground treatment that is using cement and SCS is compared, analyzed with existing ground treatment. In addition, through the laboratory tests that check the characteristic of congealment and strength, the application of SCS in field is affirmed.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1158-1163
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• 2009

In this study, PSD system to improve the soft ground was developed by using a horizontal drainage pipe. PSD system is direct drain method for the disappearance of excess pore-water pressure which is caused by fill on soft ground. To conduct the field test construction in order to evaluate application of the PSD system. To estimate the behavior characteristics on settlement in which constructed by PSD system and compared the behavior characteristics with the conventional soft ground improvement method result.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.41-48
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• 2000

Most land development projects and large scale civil works require a great amount of sand. And sand is also the most favorable material for soft ground improvement. The demand for sand is soaring rapidly due to increased number of projects regardless of its limited supply. Therefore, it is not difficult to predict that sand may become depleted and no longer be available as ground improvement material in the near future. Against this backdrop, developing an inexpensive sand-substitution material with an efficient accessibility will be necessary and urgently called for. So quick lime could be recommended as the substitutional material for sand. Quick lime is now preferred by forward developed nations. If Korea is able to take advantage of its abundant supply, economical efficiency could be achieved through massive production as well as being able to take advantage of utilization of natural resources. In this respect the purpose of this paper was to estimate improvement effect of soft ground though in-situ construction of quick lime pile. In-situ construction was peformed in road construction site of soft clay and in this study quick lime from Dan-yang that was estimated prominently in aspect of engineering characteristics was used. Quick lime piles were installed by 1.5m, 2.0m, 3.0m spacing to confirm improvement effect according to spacing and installed piles are 0.4m in diameter, up to 5m in length and the density of quick piles installed is 1.4 t/㎥. Vibrating wire pore water pressure cell was installed to confirm consolidation characteristics in surrounding of quick lime piles and both laboratory test and field test were carried out to confirm strength increase. In conclusion, soft ground improvement by quick lime piles was confirmed.

• Journal of the Korean Geosynthetics Society
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• v.17 no.2
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• pp.1-7
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• 2018

The number of construction of roads and railroads in soft ground such as coastal areas and wetlands is getting increased. For this reason cases that soft ground improvement is applied are increasing. In general, many ground improvement methods consider only the working conditions at the time or only economy. But if the working condition and economy are taken into consideration together, the number of applicable construction method gets limited. In such a case, a ground improvement method using both the surface layer portion and the deep layer portion is applied. But the basic research on this is still insufficient in practice. Therefore, in this study the reinforcement effect of geogrid was investigated by carrying out the model test realizing the case in which soft surface ground improvement and depth improvement are simultaneously applied. And it was intened to understand the effect of the thickness of surface layer, the diameter and length of the improvement body on the reinforcement effect of geogrid. The result showed that the effect of the surface layer thickness is greater than the effect of the deep layer diameter. Moreover, when the surface layer is reinforced with a geogrid, the strength of the surface layer part is enhanced and this effect of a geogrid reinforcement caused the reduction of surface settlement.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.43-54
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• 2002

As construction cases of structure are increasing in the soft ground, the necessity of ground improvement is also increasing. Granular pile is one of the improvement methods for soft ground and for loose sandy soil. In domestic, SCP(Sand Compaction Pile) method using sand material has been mainly used to improve soft ground, but Granular pile with crushed-stone was not used much. However, alternative material such as crushed-stone is needed to substitute for sand due to the environmental and economical problems. In this study, staged load test and consolidation test were performed in the laboratory to observe the behavior of soft ground improved by Granular pile. In order to evaluate the characteristics such as bearing capacity, drainage, md settlement, sand and crushed-stone were applied as each pile material. The test results show that crushed-stone has higher bearing capacity and less settlement than those of sand under similar fore water pressure condition. Therefore, crushed-stone is determined to be appropriate as the substitute for sand.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.743-749
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• 2009

In this study, the field test for suction drain method which does not require a surcharge load and a sealing sheet was performed at west seashore's site constructed by the dredged and reclaimed clay. The improvements of soft ground by suction drain method was analyzed by the results of real-time field measurement, SPT(Standard Penetration Test) and laboratory tests. The results indicated that the soft ground improvement is effective the vertical drain method used with vacuum pressure rather than surcharge load with considering settlements, dissipation of pore water pressure and shear strength.