• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1081-1089
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• 2008

Highly plastic clays in their normally consolidated state are not linear but are concave upwards. Thus their compression index deceases with the increase in consolidation pressure. Likeness the e - log ${\sigma}\;_{\upsilon}\;'$ curves of the silts are not linear but are convex upwards. In this paper, conducted consolidation test with four undisturbed field soil and found that their e - log ${\sigma}\;_{\upsilon}\;'$ plots are not linear. And analyzed difference of settlement between computed value with compression index($C_c$) and computed value with improved compression index($\mathbb{C}$).

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1042-1050
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• 2008

In this study, SCP method was used by purpose to improve loose sand and soft clay that is drilled Sand Compaction Pile in underground. Settlement behavior of field analyzed through SCP method. When sand Compaction Pile drilled in clay, forming composite ground that foundation and Sand Compaction Pile behavior. According to SCP method can expect bearing capacity improvement, Settlement reduction, lateral flow protection. SCP increase the consolidation settlement of ground and it reduce settlement for that purpose increase liquefaction resistance, lateral Resistance. Because SCP had been widely used for sand. Area of Inchon-A by sand compose clay and silt to upper Ground and compose soft clay to under ground. After pre-loading, it measured settlement by extensometer and settlement extensometer that purpose of ground improvement with 13% in replacement ratio. The result analyzed settlement behavior is similar to Multi-layered Ground that it happened to elastic settlement at upper ground and to consolidation settlement at under ground.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.89-91
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• 2000

Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.

• 한국해양학회지
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• v.7 no.2
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• pp.74-85
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• 1972

This paper studied the grain size distribution of bottom sediments of Yeongil Bay which is located at the southeastern part of the Korean Peninsula. Sixty four samples collected with snapper and dredger are analyzed by roe Tap Sieve Shaker and Pipette Method. The moment parameters are calculated with the method of Friedman(1961). Most samples are composed of sand size sediments and a few samples are composed of silt and clay. The Yeongil Bay can be divided into gravel-granule zone, sand zone, and silt-clay zone. The sediments near Yeonam- Dong and Hyongsan river are moderately sorted and others are very poorly sorted according to scheme of Friedman91962). In general, sorting values are ranged from 1.0 to 3.5. The samples near Janggigap and Masin-Dong show negative and others show positive skewness values. Skewness values are ranged from -1 to 2. All samples show the leptokurtic distribution except for the samples near Masin- dong and at the deepest place near Janggigap. Kurtosis values are ranged from -1.5 to 21.9. The samples of gravel-granule zone contain more than 50% and those of silt-clay zone contain less than 50% of CaCO$\_$3/. Four different colors, black, yellow, brown and gray, are shown in the sediments of Yeongil Bay.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.155-159
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• 1993

This study was initiated to obtain the scientific information for the improvement of paddy soil. Mean values and mutual relationships of bulk density, pH values and the content of organic matter were investigated at the 124 field sites shown to be nationwide high-yielding, young seedling field s and their neighboring fields under the different soil textures and depths. The soil samples were collected and those samples were analyzed in the laboratory of Agricultural Sciences Institute. Mean values among the different soil textures and depths were estimated with loam-textured. Bulk density were significantly correlated with sand and silt in topsoil, and that were appeared to be correlated to sand, silt + clay, pH and content of organic matter highly significant in 1% level. Regression equation of soil bulk density(Y) to clay(C), orgnic matter (OM) and content of silt + clay(S+C) were as follows for the topsoil, Y=1.365+0.006C-0.003(S+C)~0.034OM (R=0.067*), and for the subsoil, Y=1.548 -0.002C-0.0007 (S+C) -0.036OM (R=0.122**).

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.35-45
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• 2010

The soil tests have been performed on the specimens obtained from about 1,150 sites including landslides and non-landslides areas in natural terrains for last 10 years. Based on the results of those tests, the average soil properties are estimated and the simple equations for estimating permeability are proposed according to geologic conditions. The average permeability in Granite and Mudstone sites is higher than other sites and the content of silt and clay in Mudstone and Gneiss sites is higher than other sites. The correlation analysis and the regression analysis were performed to estimate the coefficient of permeability according to geological conditions. As the result of the correlation analysis, the coefficient of permeability is selected as a dependent variable, and the silt and clay contents, the water contents and the dry unit weights are selected as independent variables. As the result of the regression analysis, the silt and clay contents and the void ratio were involved commonly in the linear regression equations according to geological conditions. To verify the proposed the linear regression equations, the measured result of the coefficient of permeability at other sites was compared with the result predicted with the proposed equations. As the result of comparison, there were a little bit different between them for some data. However the difference was relatively small. Therefore, the linear regression equations for estimating the coefficient of permeability according to geological conditions may be applied to Korean soils. However, these equations should be verified and corrected continuously to improve the accuracy.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1076-1086
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• 2010

Soil remediation technologies were experimented to evaluate whether the technologies could be used to apply remediation of contaminated marine sediment. In this research, marine sediments were sampled at "Ulsan" and "Jinhae" where remediation projects are considered, and then the possibility of heavy metal removal was evaluated throughout the technologies. Heavy metal concentration of silt and clay fraction was higher than that of sand fraction at "Ulsan". Heavy metal removal of the silt and clay fraction was arsenic (As) 81.5%, mercury (Hg) 93.8% by particle separation, cadmium (Cd) 72.2%, mercury (Hg) 93.8% by soil washing technology, cadmium (Cd) 70.8%, lead (Pb) 65.6% by another soil washing technology. Based on experimental results, tested particle separation and soil washing technologies could be used to remove heavy metals of sand fraction and silt and clay fraction. Heavy metal removal by soil washing technology which was composed of separation, washing and physical or chemical reaction by additives such as acid, organic solvents was more effective comparing to that of particle separation. Since heavy metal concentration of all treated samples was suitable for national soil standards, all the tested technologies were could be used not only to remove heavy metals of marine contaminated sediment but also to reuse treated samples in land.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.386-393
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• 2023

The domestic marine healing industry is undergoing significant revitalization efforts, with a focus on understanding the efficacy and effectiveness of marine healing resources. This study establishes utilization and management standards through a detailed analysis of the active components within well-recognized marine healing mud materials. Samples of mud materials were collected from domestic tidal flats. These samples exhibited an average composition of 7.87% sand, 74.95% silt, and 17.17% clay, with a combined mud content (silt+clay)(silt+clay) consistently exceeding 90%. Notably, SiO₂ emerged as the most prevalent effective ingredient at 68.4%, followed by Al₂O₃ (13.3%)>Fe₂O₃ (4.0%)>K₂O (2.9%)>Na₂O (2.3%)>MgO (1.6%)>CaO (1.0%)>TiO₂ (0.7%), in terms of average content. Subsequently, through an analysis of effective ingredients, Si, Al, Fe, K, Na, Mg, and Ca were identified as elements demonstrating significant functionality. Among these, key indicator ingredients were selected for quality control, all of which were found to possess efficacious properties. Notably, K, Mg, and Ca exhibited particularly high concentrations. Based on these findings and referencing existing literature, it is recommended that domestic tidal flat mud resources earmarked for utilization as marine healing resources should possess a raw material mud content of no less than 70.0%. Moreover, the cumulative index components K₂O+MgO+CaO should meet or exceed a threshold of 5.0% for optimal effectiveness.

• Asian Journal of Turfgrass Science
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• v.16 no.1
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• pp.31-40
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• 2002

This study was conducted to analyze the correlation of soil physical properties and growth of turfgrass on the ground of Olympic-mainstadium. Soil hardness and turf visual quality were measured at 77 plots (10m x 10m divided each) independently and analyzed correlation later. Physicochemical properties of the topsoil analyzed from three typical levels of the severely, moderately, slightly compacted areas. The ground showed high hardness at the center circle and the goal line, but low at the end line areas. On the contrary, visual quality rate of turfgrass was low at the center circle and the goal line, but high at the end line areas. The correlation was shown a significant negative value on soil hardness between turf visual quality Soil hardness seems to be accelerated by the improper soil texture of sandy loam which contained a large amount of finer particle of silt (10.7%) and clay (11.1%) which values exceeded for USGA (United State Golf Association) recommendation. Deterioration of turf quality resulted initially from improper construction and followed by high soil compaction with continuous uses of the ground without proper maintenance. To perform the international quality of the turf ground, the initial construction procedures should be followed by standard specifications of sport ground.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.423-430
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• 2004

This study intended to understand movements of turbid water in selective with drawal reservoirs before and after summer monsoon. Mean rainfall during November-May was low, compared to that during June-October. The reservoir water was discharged through watergates when previous rainfall and inflow exceeded 50 mm and $80\;m^3s^{-1}$, respectively. Intake towers were generally used except for the period of the high runoff. Average turbidity in gown-reservoir showed a difference of 29.9 NTU between premonsoon and postmonsoon. Diameter of particles of turbid water ranged between 0.435 and $482.9\;{\mu}m$. Fine particles such as clay were much denser than the larger particle. In the whole stations, clay component was relatively higher with a proportion of that in the particle distribution. Particle composition of turbid water showed that clay consisted of 94.4-98.9% and silt made of 1.1-5.6%. Analysis on turbid water movements derived from particle distribution showed a linear increase from the deep layer toward the surface layer in lower area of a reservoir. This was closely related with the hydraulic behavior of the reservoir, and heavily affected by the discharges through selective withdrawal towers and watergates. Turbid water originated from stream sediments in the middle area then resuspended in the down-reservoir causing a movement between the surface and middle layers of the reservoir. Therefore, such phenomenon needs to be understood for reservoir water quality management.