• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.569-576
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• 2002

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, to compare the soil and sand-mat mixed method with sand-air jet method for shallow improvement of hydraulic fills at southern seashore, the model tests were performed. Through the model test results, the behavior of surface as disturbance of desiccation crust is analyzed.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.561-568
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• 2002

PFA(Paper Fly Ash) are reclaimed mainly or used in cement industry field as mixture agent in terms of materials recycling. Recently, research for recycling PFA as embankment materials or soil stabilization agent are undergoing in geotechnical engineering field. In this study, physical characteristics of PFA stabilization agent-soil admixtures are examined in change of water content, void ratio, consistency, grain distribution, specific gravity and density. Futhermore, the physical characteristics are compared with unconfined strength as engineering characteristics. Test results showed that unconfined strength and density are increased with increasing of PFA stabilization agent mixed ratio. On the other hand, specific gravity, void ratio and water content are decreased with increasing of PFA stabilization agent mixed ratio. It would be concluded that natural high water content ratio weak soil could be highly improved engineering and physical characteristics with PFA stabilization agent

• Journal of the Korean GEO-environmental Society
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• v.7 no.3
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• pp.5-19
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• 2006

The secondary consolidation settlement of soft clay is generally very little compared to the total settlement and occurs very slowly during long-term period. However the secondary consolidation settlement is comparatively large amount in organic and heavily compressed clay and is a very important engineering factor. In order to reduce residual settlements in reclaimed soft ground, the preloading method is often used. In this study, in order to determine reasonable long-term settlements of large reclaimed site, laboratory incremental loading consolidation tests and surcharging consolidation tests are performed. Sampling was done at Incheon area of west coast and Gwangyang area of south coast in Korea. The characteristics of secondary consolidation have obtained through laboratory tests and analyzed systematically to predict long-term settlements. Additionally, the location data and laboratory test results are correlated by using GIS(geographic information system). The secondary consolidation settlement of the site was predicted based on D/B and the operation technique and estimation technique of space of GIS.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.62-66
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• 1997

This study was designed to obtain the mean values of thirteen soil physico-chemical properties for different paddy soil management groups, and to serve the basic information for improving the soil using amendments. Computerized data on the results of detailed soil survey were used in this study. The clay contents in the B horizon of paddy soil management groups were 28.3% in the well adapted type, 11.8% in the sandy textured type, and 26.8% in the newly reclaimed type. Soil pH of B horizon in the paddy soil management groups except poorly drained type and acid sulfate type were higher than those of A horizon. In the river side paddy soils of well adapted type, the clay contents of A and B horizons were 16.8%, 23.1%, respectively, and soil organic matter contents of those horizons were 42g/kg, 18g/kg, respectively. And also available phosphate content of well adapted type was higher than the other types. Frequency of distribution of soil organic matter content levels in the B horizons of sandy textured type and newly reclaimed type were higher in the organic matter content range of below 10g/kg. And those of well adapted, poorly drained, and saline type were higher in the organic matter content range of 10~20g/kg. Correlation coefficients between 13 variables in the B horizon of well adapted type were all highly significant at 1% or 5% level, respectively.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.85-92
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• 2015

This study examined the settlement of a 1-2W type greenhouse using a timber pile, which was recently established on Gyehwa-do reclaimed land, in order to obtain base data for the construction of a greenhouse on reclaimed land. The results of this study are as follows. foundation and timber pile increased over time, irrespective of the interior and exterior of the upon investigation of the ground, it was confirmed that there was no soft rock stratum (bedrock), and that a sedimentary stratum existed under the fill deposit, which is estimated to have been reclaimed during the site renovation. It was also found that a weathered zone was located under the fill deposit and sedimentary stratum, and that the soil texture of the entire ground floor consisted of clay mixed with sand, silty clay, and granite gneiss, in that order, regardless of boreholes. In addition, the underground water level was 0.3m below ground, regardless of boreholes. Despite a slight difference, the settlement of the greenhouse or measurement sites (channels). With regard to the pillar inside the greenhouse, except in the case of CH-2, the data at a site located on the side wall of the greenhouse (wind barrier side) indicated vibrations of relatively larger amplitude. Moreover, the settlement showed a significant increase during a certain period, which was subsequently somewhat reversed. Based on these phenomena, it was verified that the settlement range of each site in the interior and exterior of the greenhouse was between 1.0 and 7.5mm at this time, except in the case of CH-1. The results of the regression analysis indicated good correlation, with the coefficient of determination by site ranging between 0.6362 and 0.9340. Furthermore, the coefficient of determination ranged between 0.6046 and 0.8822 on the exterior of the greenhouse, which is lower than inside the greenhouse, but still indicates significant correlation.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.281-290
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• 1999

The coastal area, particularly along the West and South coasts in Korea, is often reclaimed with dredged marine-clay to meet the demand of land capacity. A large number of ground improvement techniques are developed for such a newly formed soft clay deposit. However, the quick lime column method, which is effectively used for the purpose of ground improvement in the other countries, is seldom applied in Korea. This study, therefore, focuses on the development of appropriate soft soil improvement technique by using quick lime column. A model test as well as finite element analysis was conducted to identify the consolidation characteristics around the lime column. Although actual pore water pressure measured from model tests does not coincide with the predictions made by finite element method and Chen ＆ Law's theoretical formula, their trends are quite similar. It is revealed from this study that the pressure caused by the expansion of lime column affects considerably the consolidation characteristics of the surrounding ground.

• Journal of the Korean Geosynthetics Society
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• v.3 no.1
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• pp.17-25
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• 2004

A horizontal drain method, which applies vacuum pressure at the end of a horizontal drain for discharging pore water, is used often for improving surface reclaimed clay in the field. In this study, to examine the effectiveness of improving consolidation or shear strength depends by varying vacuum pressure, laboratory chamber horizontal drain test using vacuum pressure is performed and the results is compared with that of self-weight consolidation. The results show that water content reduces with the increase of soil depth in case of self-weight consolidation, while it reduces near the horizontal drain and increases with the increase of the distance from the horizontal drain in case of applying vacuum pressure. The shear strength of dredged soil was improved as well, when the vacuum pressure is applied. The optimized consolidation was achieved at the vacuum pressure range of 30 to 50kPa in the laboratory box test of 50cm wide, considering the range of drain interval in the field was between 0.7 and 1.2m.

• Journal of the Korean Geotechnical Society
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• v.25 no.6
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• pp.73-88
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• 2009

Geotechnical variability is a complex feature that results from many independent sources of uncertainties, and is mainly affected by inherent variability and measurement errors. This study evaluates the coefficient of variation (COV) of soil properties and soil layers at Song-do region in Korea. Since soil variability is sensitive to soil layers and soil types, the Cays by soil layers (reclaimed layer and marine layer) and the COVs by soil types (clay and silt) were separately evaluated. It is observed that geotechnical variability of marine layer and clay is relatively smaller than that of reclamation layer and silt. And, the highly weathered rock and soil show the higher cays in the interpretation of the strength parameters of the fresh and weathered rock. And the proposed COV of Songdo area can be used for the reliability-based design procedure.

• Journal of the Korean GEO-environmental Society
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• v.8 no.1
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• pp.13-20
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• 2007

Leachates resulting from the waste landfill of waste can possibly cause the second pollution, such as the underground water and environmental pollution. Accordingly, Liner layer has been installed in the reclaimed land of waste to block and purify permeation water to and prevent this second pollution. The material used as Liner layer should have water resistance and be less than permeability coefficient of $1{\times}10^{-7}$ cm/sec. As it is very difficult to get this kind of natural clay with low permeability around the field, the suitable way to get the low permeable material is to use blend with good watertighness by mixing it with natural soil which is spread in the site. While this mixed soil, which can resist water, is commonly used in the site, namely, bentonite and MCG cementious mateiral mixed soil, which is widely used as Liner layer in the reclaimed land of waste, is recognized in Liner and durability. The study was performed to find the effect of additive of the bottom liner in the waste landfill. The aim of this paper is to explain of the field application examples as well as the data of experimental research with the engineering properties of Liner layer of the reclaimed land.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1234-1242
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• 2010

In this study, the effect of noise and vibration, and influence of ground improvement are evaluated and its application is analyzed through the example of SCP designed at ground improvement in Song-Do international city. consequently, it showes even comfortable result that it is about 5.0m of inner space, when the LVSCP method is applied, rather than that it is about 30m of inner space when the existing SCP is applied in vibration control standards 2.0mm/sec. In the noise, now that the many differences according to environmental factors like other equipment noise, limited space and so on at the time of the construction by LVSCP method are coming out, so we think that appro itate measures are needed according to surroundings. By the way, when it comes to the estimation of the ground improvement work before and after an improvement of LVSCP method, its result shows that it is satisfacttion to all the standards of compaction control in dregded and reclaimed ground and sedimentary clay layer.