• 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.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.45-55
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• 2015

In Incheon area, 1960s of economic development planning and heavy industry center of efforts industrial park and port facilities, It is industrial land reclamation by coastal landfill, these industrial park has the characteristics of Low permeability lipid is embedded in the silty sand that was dredged. In this study, To evaluate the heavy metal adsorption ability to filter of drains that have been developed as environmentally friendly materials by applying the effective zeolite to heavy metal adsorption for soil pollution purification suitable for geological characteristics of Incheon. soil pollution Survey data and Literature search, which is the current through the industry, the most problematic was set to Cadmium (Cd) and Copper(Cu), Lead (Pb). and Using the Numerical Analysis using the Visual Modflow, was presented the most efficient drains set interval and format.

• Journal of Ocean Engineering and Technology
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• v.21 no.2 s.75
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• pp.22-34
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• 2007

We present basic data for developing new research topics and closely examine the existing data on the development and organization of the Nakdong River Estuary Delta by analyzing various studies of the area, including ocean engineering, coastal engineering, ocean environmental engineering, geomorphological, and geological studies. We first defined the general concepts related to the estuary and delta and reviewed the historical development of the Nakdong River Estuary Delta over the past 100 years. We then examined the origin and core elements of the estuary deposits that constitute the delta. In addition, we scrutinized the main factors affecting the development of the delta and analyzed existing research on delta development mechanisms by core researchers. The construction of an estuary barrage is one of the main factors effecting estuarine circulation and has altered the physical oceanic environment, area of deposition, atmospheric environment, and vegetation community of the delta. These factors affect the estuary circulation in turn, altering the delta. Along the Nakdong River, an unsteady-state sandy barrier appears at approximately three times the distance of the wavelength of incident offshore waves, and this terrain forms approximately 10-15 years after reclamation in the interdistributary upper stream and transforms the shoreline. It is necessary to develop a technique to predict terrain change that reproduces the erosion and accumulation of estuarine deposits. To determine the parameters and variables necessary to reproduce this system, continuous on-site monitoring is necessary. The existing research did not fully examine the terrain changes in Nakdong River Estuary or the periodic developmental characteristics. To understand the future process of estuary delta development, it is necessary to establish an integrated management system.

• ALGAE
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• v.20 no.4
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• pp.379-388
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• 2005

Seagrass bed is an important component in coastal and estuarine ecosystems, providing food and shelter to a wide variety of fauna. Recently, seagrass coverage has declined significantly due to anthropogenic influences such as reclamation, dredging, and eutrophication and consequently, necessity of seagrass habitat restoration is rising. Transplantation experiments with Zostera marina using TERFS, staple method, and shell method have been conducted at Dadae Bay, Kosung Bay and Jindong Bay on the south coast of Korea to select an optimal transplanting method for restoration of Z. marina habitat. Three experimental sites located at the vicinity of natural Z. marina beds with an average water depth of about 4m. Z. marina plants, which were collected from donor bed in Koje Bay were also transplanted at 7 different time from October 2003 to July 2004 to find appropriate transplanting time. Density of Z. marina was monitored monthly at both transplanted areas and natural beds. Transplantation using the staple method showed the highest survival rate of transplant. Shell method was also an effective transplanting method at muddy areas in Kosung Bay and Jindong Bay, but not suitable at sandy areas in Dadae Bay. These results suggest that sediment composition of transplanting areas should be considered for the selection of the optimal transplanting method. Z. marina transplanted during fall usually showed the highest survival rate, while most Z. marina plants transplanted in summer died due to high lethal temperature during this period.

• The Korean Journal of Ecology
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• v.24 no.1
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• pp.27-34
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• 2001

We described the vegetation of a disturbed lagoon wetland in relation to water and soil environments in Kungae lagoon reclaimed 30 years ago. Water depth and soil organic matter showed a great spatial heterogeneity in Kungae wetland which was changed into a freshwater marsh by the dike construction. Detrended canonical correspondence analysis suggested that differences in vegetation structure were primarily the result of variation in water depth or microtopography and soil organic matter Various emergent vegetations were developed in the wetland: species such as Phragmites australis, Calamagrostis epigeios, Carex dispalata and Lythrum anceps in a wide area, hydrophyes such as Typha angustifolia and Scirpus tabernaemontani at the low elevation with deep water, ruderals such as Bidens frondosa and Persicaria perfoliata near upland with much soil organic matter and sand-dune vegetation such as Carex kobomugi, Diodia tens, Pinus thunbergii and Potentilla egedei var. groenlandica at the high elevation. These results suggest that development of a prototype for wetland restoration from vegetation analysis of other natural lagoons and restoration of natural water tables and hydrologic connections between the diked wetland and the sea are important in the disturbed Kungae wetland.

• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.63-72
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• 2014

To observe the behavior of lateral deformation of buried pipe and the preventing effect of embankment piles against the lateral deformation, a series of full-scale field tests were performed on a reclaimed coastal area. A buried pipe was installed in the west coast undergoing reclamation and embankment was performed by three steps. Then vertical settlement and lateral displacement were measured by the settlement plate and the inclinometer. Embankment pile system were applied to prevent the lateral displacement of buried pipe. Heave of the buried pipe slightly happens during embankment and following settlement. Finally the behavior steadily converged. The preventing effect of the embankment pile was approximately two times stronger than non-reinforcement. Both settlement and lateral displacement appear to be bigger at upper ground and smaller at lower ground.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.15-25
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• 2018

The accident risk at the construction workplace associated with agricultural engineering is comparatively higher than those of other fields due mainly to its complex work types and processes. Agricultural engineering deals with a variety of agricultural infrastructures from irrigation and drainage facilities to giant-scale coastal reclamation land infrastructures. The characteristics that most agricultural projects have conducted on a small-scale even worsen the situation drawing low attentions to risk management. Therefore, systematical risk assessment that focuses on details of agricultural construction work process is required in order to enhance safety management capacity and to prevent repetitive accidents ultimately. This study aims to categorize construction work types and processes of agricultural construction works, and to quantitatively assess the accident risk of them based on accident analysis. Regarding classification of construction works, actual 827 accident cases were thoroughly reviewed and coded by their construction site, facility and work type, project scale and so on. Most accidents (71.8 % of total cases) occurred in small-scale construction workplaces with less than 5 billion Korean won project budget. And those accidents related to agricultural infrastructure project (37.4%) and agricultural water development project (22.4%). In terms of work types, accidents frequently took place in form-work followed by pipe installation work, steel bar work and concrete work. The potential risks were compared with actual outbreak of accidents based on Analytic Hierarchy Process (AHP). The results show that the potential conditions of accident expected to be took place is somewhat different from the actual conditions where accidents actually happened. This implicates that risk management manuals or education needs to be adjusted by reflecting unexpected circumstances. Overall, this study is meaningful in that the results could be foundations as to strengthen risk management capacity for agricultural engineering projects.

• Journal of the Korean Geosynthetics Society
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• v.13 no.2
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• pp.11-20
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• 2014

To create a large-scale complex, it is often the case to perform ground improvement by using vertical drain method after the reclamation of coastal soft ground, for construction period shortening and stable site renovation. During this process, the pore water migrates to the horizontal drainage layer of the ground surface through the vertical drain installed in the soft ground and discharged out to the open. In the past sand was used as the material for the horizontal drainage layer in numerous cases, however recently, due to material shortage and high pricing, the use of crushed stones has increased. To prevent mixing of the materials between the horizontal drainage layer and the upper landfill, geosynthetics (PPMat) are installed. However, the use of geosynthetics results in high additional cost for material purchase and installation, therefore it is necessary to examine the validity of the installation itself. In this study, to verify the necessity, model tests were performed. Results from the model tests indicate that the drainage ability of the horizontal drainage layer is barely affected by the application of geosynthetics.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.262-270
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• 2015

The scientific information between microbial community and chemical properties of reclaimed tidal soil is not enough to understand the land reclamation process. This study was conducted to investigate the relation between chemical properties and microbial activities of soils from reclaimed tidal lands located at south-western coastal area (42 samples from Goheuong, Samsan, Bojun, Kunnae, Hwaong and Yeongsangang sites). Most of the reclaimed soils showed chemical characteristics as salinity soil based on EC. Only $Na^+$ in exchangeable cation was dependent on EC of reclaimed soil, whereas other cations such as $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were independent on EC. The mesophilic bacteria decreased with an increase in EC of soil. Microbial population increased with soil organic content in the range of $0{\sim}10g\;kg^{-1}$ and dehydrogenase activity less than $100{\mu}g-TPF\;g^{-1}h^{-1}$. Microbial population of soils from reclaimed tidal lands was closely related to the microbial community containing hydrolytic enzyme activities of cellulase, amylase, protease, and lipase.

• Journal of the Korean Geotechnical Society
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• v.25 no.12
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• pp.37-45
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• 2009

Dredging and reclamation which have been conducted steadily for creation of new coastal area have the demerit of taking a long time. Hence, a lot of researches on acceleration of self-weight consolidation have been proceeding continuously. In this paper, 30 cases of laboratory self-weight consolidation tests were conducted to understand the application of PDF method, one of the self-weight consolidation acceleration methods, to domestic dredged soils. Acceleration effect of self-weight consolidation was confirmed through comparison and analysis of completion times and settlements of self-weight consolidation for none installed case and 4 kinds of common used PBD installed cases. As a result of the tests, installation of PBD before filling is effective for time reduction of self-weight consolidation.