• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.105-116
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• 1999

The Inchon International Airport site was formed by reclaimed soil from the sea. The average thickness of soft soil Is about 5 m and most of soft soils are normally consolidated or slightly over consolidated. There are many box culverts which are being constructed under the runways in the airfield. Sometimes, differential settlement can be occurred in the adjacent of box culvert or underground structures at the top layer of runway Soil compaction at very near to the structure is not easy all the time. Thus, one layer of geogrid was placed at the bottom of lean concrete layer for the concrete paved runway and at the middle of cement stabilized sub-base course layer for the asphalt paved runway. The length of geogrid reinforcement is 5m from the end of box culvert for both sides. The extended length of geogrid was 2m from the end of backfill soil in the box culvert. The tensile strength tests of geogrid were conducted for make sure the chemical compatibility with cement treated sub-base material. The location of geogrid placement for the concrete paved runway was evaluated. The construction damage to the geogrid could be occurred. Because the cement treated sub-base layer or lean concrete was spread by the finisher. The magnitude of tensile strength reduction was 1.16%~1.90% due to the construction damage and the ultimate tensile strength is maintained with the specification required. Total area of geogrid placement in this project is about 50,000 $m^2$.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1065-1072
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• 2010

The excavation site in the new city of inchon songdo is distributed with soft reclaimed soil and marine deposit. So, the general ground anchor is not applied to this layer of soft ground as the earth retaining support system, because of settlement. And then, Jacket pack anchor which is newly developed in order to increasing the pullout resistance by certain grout bulb formation and expansion effect in soft ground is applied to this site instead of the general ground anchor. Though the maximum horizontal displacement shows about 30mm~100mm (The maximum horizontal displacement/excavation depth$\fallingdotseq$0.32~1.0%) according to excavation sequence, generally excavation work finished stably. Also, load cell after setting shows almost increasing trend with increasing horizontal displacement. It means that the settlement of Jacket pack anchor in soft ground is good. From the result of this case, we knew that Jacket pack anchor was able to use the earth retaining support system in soft ground. Using Jacket pack anchor in soft ground, The allowance of the horizontal displacement is applied more than general value considering soil factors.

• Journal of Environmental Impact Assessment
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• v.20 no.5
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• pp.675-684
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• 2011

In nature, the overall effect of heavy metals on the biota can be influenced by a number of environmental factors like soil characteristics and air pollution by elevated $CO_2$. Pillbugs (Isopoda, Armadillium vulgare) take up heavy metals with their food and store them mainly in the vesicles of hepatopancreas. They accumulate certain metals, occur in relatively large numbers, are easily collected and identified, and provide sufficient material for analysis. The species are decomposing litter well and soil impurities into N and P. Therefore, it has been suggested that total body concentration of metals in pillbugs could be positively correlated to the levels of environmental exposure and that pillbugs could be used as biological indicators of metal pollution and global change by $CO_2$. The aim of the study is to determine effects of heavy metal concentrations in soil and elevated $CO_2$ on pillbugs' body accumulation of heavy metal and growth rate. In this study, the concentrations of six metals (Fe, Mg Cu, Zn, Pb, Cd) have been determined. Pillbugs (N=287) were collected at five sites during Jul-Aug, 2006. Cu and Zn concentrations in the body were much higher than in the soils(1.39-41.70 times). This indicated that bioaccumulation of some of the heavy metals were increasing in the food-chain. The high bioconcentration of lead in Sangam may be partly associated with reclaimed land uses.

• 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 Geotechnical Society
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• v.15 no.6
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• pp.219-238
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• 1999

In the present study, laboratory tests including the seepage-induced consolidation test, suction test, and desiccation shrinkage test are performed to investigate characteristics of the desiccation shrinkage in reclaimed hydraulic fills. Soil samples for laboratory tests are obtained from three sites (districts of Haenam, Kogeum and Koheung in Chunnam area). Desiccation shrinkage settlement caused by three dimensional volume change is numerically evaluated using finite difference technique based on the governing equation proposed by Abu-Hejleh & Znidarcic. Also characteristics of the desiccation shrinkage analyzed from the test results are used as input data for numerical evaluations. Further predicted total settlements including the self-weight consolidation settlement are compared with values measured at the site of Haenam district. Finally, effects of parameters related to the desiccation shrinkage on settlements are examined.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.117-122
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• 2007

This experiment was carried out to select the optimum forage cropping system at the Dae-Ho reclaimed tideland, Korea from March, 2004 to October, 2006. Emergency rate of summer crop such as sorghum ${\times}$ sudangrass was low ($23%{\sim}30%$). Winter crop such as Italian ryegrass after continually cultivating wholecrop rice were highest (91%). Wintering rate of Italian ryegrass after continually cultivating wholecrop rice was highest and lowest in wholecrop barley after continually cultivating sorghum${\times}$sudanuass. In cropping system, fresh and dry matter yield of annually wholecrop rice+Italian ryegrass (50,807kg, 15,065kg) were highest and lowest in annaually serghum${\times}$sudangrass+wholecrop barley (17,2471kg, 5,209kg), respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.4
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• pp.247-262
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• 1979

Majority of reclaimable soils in hillside lands in Korea are red yellow soils, with exception in Jeju island, where most of reclaimable hillside lands are composed of volcanic ash soils. Songjeong, Yesan and Samgag series are the major soil series of red yellow soils which are available for the reclamation. When observed in the fields, they are distinguished as reddish brown clay loam, red yellow sand loam and yellowish brown sand loam. They have moderately good physical properties but their chemical properties are generally poor for crop cultivations. The chemical properties of red yellow soils, as compared to long time cultivated (matured) soils, are characterized by very low pH, high in exchangeable Al content and phosphorus fixation capacity. Also extraodinary low available phosphorus and organic matter contents are generally observed. On the other, the chemical properties of volcanic ash soils are characterized by high armophous Fe and Al hydroxides and organic matter contents, which are the causative factors for the extremely high phosphorus fixation capacity of the soils. The phosphorus fixation capacity of volcanic acid soils are as high as 5-10 times of that of red yellow soils. Poor growth of crops on newly reclaimed red yellow soils are mainly caused by very low available P and pH and high exchangeable Al. Relatively high P fixation capacity renders the failure of effective use of applied P when the amount of application is not sufficient. Applications of lime to remove the exchangeable Al and relatively large quantity of P to lower the P fixation capacity and to increase the available P are the major recommendations for the increased crop production on red yellow hillside soils. Generally recommendable amounts of lime and P to meet the aforementioned requirements, are 200-250kg/10a of lime and $30-35kg\;P_2O_5/10a$. Over doses of lime. frequently induces the K, B, arid Zn deficiencies and lowers the uptake of P. In volcanic ash soils, it is difficult to alter the exchangeable Al and the P fixation capacity by liming and P application. This may be due to the peculiarity of volcanic ash soil in chemical properties. Because of this feature, the amelioration of volcanic ash soils is not as easy as in the case of red yellow soils. Application of P as high as $100kg\;P_2O_5/10a$ is needed to bring forth the significant yield response in barley. Combined applications of appropriate levels of P, lime, and organic matter, accompanied by deep plowing, results in around doubling of the yields of various crops on newly reclaimed red yellow soils.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.56-63
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• 1983

On a newly reclaimed soil, an experiment was carried out for the elucidation of proper rate of phosphorus fertilizer and application method to increase soybean yield in Honam area. 1. The yield was high in whole layer placement of phosphorus fertilizer and low in deep placement. 2. Broadcasting with 15% of phosphate fixation coefficent and whole layer and deep placement of fertilizer with 10% of phosphate fixation coefficent showed maximum yield. 3. Large application of phosphate increased stem diameter and number of blanches and podes. 4. Application of phosphorus fertilizer increased phosphate content in soil from 9 ppm to 48-223 ppm and contents of bases 5. Significant positive correlation was obtained between soybean yield and phosphorus uptake amount.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.190-194
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• 1982

The differences in soil productivity between the cut site and the fill site in a newly reclaimed land were compared with the experimental results conducted during 1978 to 1980 under soybean-barley and sweet potato-barley cropping systems. The results were summerized as follows; The bulk density of the cut site was near $1.5g/cm^3$ with the hardness above 23mm by Yamanaka method and that of the fill site was $1.3g/cm^3$ with the hardness of 14mm at the first year of reclaiming. The bulk densities and soil hardnesses asymptotically approched to $1.4g/cm^3$ and 19mm, respectively. The chemical productivity of the fill site was also significantly higher than that of the cut site. Differently from the bulk density and hardness, chemical compositions of the fill site maintained high untill the third year of cropping. The yields of soybean, sweet potato and barley from the cut site at the first year were very poor and, thereafter, were remarkably increased by 2 to 9 times at the third year of cropping while those from the fill site maintained high from the first year to the third year of cropping.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.145-150
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• 2007

This study was conducted to evaluate the application effects of phospho-gypsum fertilizer (PGF) as reclamation material in the newly reclaimed paddy fields located in Goheung and Youngam, Jeonnam province in Korea. The PGF used in this experiment was produced by Namhae Chemical Co. as the name of Soil-Saver$^{TM}$. Prior to rice transplanting, the PGF was applied as soil amendment as the amount of $3,000kg\;ha^{-1}$. The PGF increases rice plant height and number of tiller at the heading stage by 119.9 cm and 9.1, respectively, in Youngam area. The harvest index of brown rice increased up to 5 and 13% more in the PGF applied paddy field from both sites than in the non-application of PGF at paddy field before rice transplanting, and the ripening ratio in increased in both sites to 81 and 90%. Protein content of brown rice was also greater than in the non-application of PGF at the both sites. For the effects of the reclamation by PGF in the paddy field soils, we found that PGF reduced exchangeable Na to 18 and 28% for both sites, respectively, and increased exchangeable Ca and $SO_4$. And we found relatively higher amounts of $K_2O$, CaO and MgO in the rice plants from both sites applied with PGF.