• Journal of the Korean GEO-environmental Society
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• v.19 no.1
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• pp.15-23
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• 2018

In this study we performed risk evaluation based on parameters using the SINMAP, GIS-based extended program in order to predict ground disaster that is frequent recently. As for the risk evaluation, in order to understand the effects of parameters, we defined that the ranges of internal friction angles and T/R values as important variables had three and four patterns, respectively. The results of the interpretation were compared with those of the existing landslide in order to identify landslide flow and to evaluate the applicability of the parameters. The analysis of the geomorphologic saturated zone showed that the boundary saturated zone and the saturated zone were almost consistent with the site of avalanche of earth and rocks and the area of underground water convergence was correlated to the area where collapse started, indicating that the geomorphologic saturated zone may serve as an index for estimating possibility of landslide when used with slope distribution, colluvial soil, and structures inducing landslide in combination. When the lower limit of the internal friction angle increased more, the upper threshold decreased by 50 to 70% and the influence on the stability index was higher, but the influence was declined within the range of lower wetness index. The analysis of changes based on wetness index range showed that all the groups have similar SI distribution, except for the one in which mean altitude values are applied, indicating that the results are susceptible more by the internal friction angle than by the wetness index.

• Journal of the Korean Geotechnical Society
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• v.29 no.7
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• pp.75-89
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• 2013

This paper describes a GIS-based geohydrologic methodology, called YSGWF (YonSei GroundWater Flow) for predicting the rainfall infiltration-groundwater flow of slopes. This physical-based model was developed by the combination of modified Green-Ampt model that considers the unsaturated soil parameters and GIS-based raster model using Darcy's law that reflects the groundwater flow. In the model, raster data are used to simulate the three dimensional inclination of bedrock surface as actual topographic data, and the groundwater flow is governed by the slope. Also, soil profile is ideally subdivided into three zones, i.e., the wetting band zone, partially saturated zone, and fully saturated zone. In the wetting band and partially saturated zones the vertical infiltration of water (rainfall) from surface into ground is modeled. When the infiltrated water recharges into the fully saturated zone, the horizontal flow of groundwater is introduced. A comparison between the numerical calculation and real landslide data shows a reasonable agreement, which indicate that the model can be used to simulate real rainfall infiltration-groundwater flow.

• Journal of the Korean GEO-environmental Society
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• v.4 no.2
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• pp.39-46
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• 2003

An immobilization zone can be constructed by modifying soils in the vadose zone with surfactants, which can be used to promote retardation of organic contaminants in the subsurface. Column experiments were conducted to investigate the behavior of surfactants and organic contaminants in unsaturated and saturated conditions with different water contents (25%, 50%, 75%, 100%). Transport and sorption of surfactant (dialkylated disulfonated diphenyl oxide) in the columns containing aluminum oxide was similar under the conditions at different water contents. However, transport of a model organic compound (naphthalene) was retarded as the water content decreased by enhanced partitioning of the compound into the surfactants that were sorbed on the aluminum oxide. This suggests that the immobilization method could well be applied to vadose zone as well as to saturated zone.

• Economic and Environmental Geology
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• v.36 no.4
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• pp.285-293
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• 2003

Tailings of Dukum mine in the vadose and saturated zone were investigated to reveal the mobility of metal elements and the condition of mineralogical solubility according to redox environments throughout the geochemical analysis, thermodynamic modelling, and mineralogical study for solid-samples and water samples(vadose zone; distilled water: tailings=5 : 1 reacted, saturated zone; pore-water extracted). In the vadose zone, sulfide oxidation has generated low-pH(2.72∼6.91) condition and high concentration levels of S $O_4$$^{2-}$(561∼1430mg/L) and other metals(Zn : 0.12∼l57 mg/L, Pb : 0.06∼0.83 mg/L, Cd : 0.06∼l.35 mg/L). Jarosite$(KFe_3(SO_4)_2(OH)_6)$ and gypsum$(CaSO_4{\cdot}2H_2O$) were identified on XRD patterns and thermodynamics modelling. In the saturated zone, concentration of metal ions decreased because pH values were neutral(7.25∼8.10). But Fe and Mn susceptible to redox potential increased by low-pe values(7.40∼3.40) as the depth increased. Rhodochrosite$(MnCO_3)$ identified by XRD and thermodynamics modelling suggested that $Mn^{4+}$ or $Mn^{3+}$ was reduced to $Mn^{2+}$. Along pH conditions, concentrations of dissolved metal ions has been most abundant in vadose zone throughout borehole samples. It was observed that pH had more effect on metal solubilities than redox potential. How-ever, the release of co-precipitated heavy metals following the dissolution of Fe-Mn oxyhydroxides could be the mechanism by which reduced condition affected heavy metal solubility considering the decrease of pe as depth increased in tile saturated zone.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.265-268
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• 2002

The ground water regime analysis method, numerical analysis method, water budget method, and baseflow analysis method have been used for estimating ground water recharged quantity. This study, adapting water budget concept of unsaturated zone, and saturated zone of the DAWAST model, proposed a new method to estimate ground water recharged quantity.

• Korean Journal of Hydrosciences
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• v.2
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• pp.13-24
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• 1991

The governing partial differential equation of flow in porous media is developed on the bases of the continuity equation of fluid for transient flow through a saturated-unsaturated zone, and substitution of Dercy's law. The numerical solution is obtained by the Galerkin finite element method based on the principle of weighted residuals. The analysis is carried out by using the unsteady storm data observed and the functional relationships between the hydraulic conductivities, capillary pressure heads, and volumetric water contents under saturated-unsaturated conditions. As the results the hydraulic conductivities, rates of change of storage and initial moisture conditions are significantly influened on the responses of subsurface flow on a hillslope.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.398-406
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• 2012

The acid value of the oil extracted from the three kinds of 15 fried foods ranged from 0.89 to 3.92, the peroxide value ranged 10.0~57.14 meg/kg. Among the samples, popcorn chicken contained the highest crude fat content, showing $6.64{\pm}0.26(%)$, while the french-fries showed $2.87{\pm}0.31(%)$, which was the lowest. The content of the trans fatty acid per 100 g of the foods were; the fried foods: 0.02~0.06 g. The french-fries contained the lowest saturated fatty acid per 100 g of the foods, showing 0.41~1.55 g, while the popcorn chicken showed the highest content, 1.16~3.43 g. The fried foods contained the highest linoleic acid content. Further, fried foods exhibited safe levels of trans fat content. The "School Zone", which sells snacks, candies, chocolates flow, was not detected in the saccharin. Cookies, candies, chocolate was not detected in the tar colors. Aerobic plate count were ranged from 0~4,700 cfu/g in cookies, Salmonella test came out negative.

• Computers and Concrete
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• v.21 no.1
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• pp.67-74
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• 2018

A differential scheme based micromechanical framework is proposed to obtain the effective properties of the saturated concrete repaired by the electrochemical deposition method (EDM) considering the interfacial transition zone (ITZ) effects. The constituents of the repaired concrete are treated as different phases, consisting of (micro-)cracks, (micro-)voids and (micro-)pores (occupied by water), deposition products, intrinsic concrete made up by the three traditional solid phases (i.e., mortar, coarse aggregates and their interfaces) and the ITZs. By incorporating the composite sphere assemblage (CSA) model and the differential approach, a new multilevel homogenization scheme is utilized to quantitatively estimate the mechanical performance of the repaired concrete with the ITZs. The CSA model is modified to obtain the effective properties of the equivalent particle, which is a three-phase composite made up of the water, deposition products and the ITZs. The differential scheme is employed to reach the equivalent composite of the concrete repaired by EDM considering the ITZ effects. Moreover, modification procedures considering the ITZ effects are presented to attain the properties of the repaired concrete in the dry state. Results in this study are compared with those of the existing models and the experimental data. It is found that the predictions herein agree better with the experimental data than the previous models.

• Journal of the Korean Geotechnical Society
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• v.28 no.5
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• pp.27-39
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• 2012

In this paper, a series of centrifuge tests were performed to evaluate the seepage characteristic of reinforced embankment. The centrifuge models simulated an actual embankment reinforced by enlargement of levee cross-section. The centrifuge models have the same conditions except the locations of enlargement with low permeable material : water-side and land-side. In addition, the prototype embankment is constructed on low permeable clay layer. In the case of water-side reinforcement, the reinforced zone makes water head down and the saturated zone of embankment propagates slowly. In the case of land-side reinforcement embankment, the saturated zone enlarged relatively faster but the amount of exit water at land-side toe was very small because of the land-side reinforcement zone. The low permeable clay foundation layer was being continuously saturated by the inflow from the embankment as well as the uplift flow from the permeable layer induced by the excess pore water pressure.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.185-193
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• 2004

A physical model experiment was conducted using a sand and gravel-filled tank model, to investigate the influence on the GPR response of LNAPL vapor phase effects in the unsaturated zone and of residual phase of LNAPL trapped in the saturated zone. Background measurements of GPR were made with only water in the tank using a fluctuating water table model. Gasoline was, then, injected into the bottom of the model tank to simulate a subsurface discharge from a leaking pipe or tank at depth, obtaining GPR data with rising and lowering of water table. Results from the experiment show the GPR sensitivity to the changes in the moisture content in the vadose zone and its effectiveness for monitoring minor fluctuation of the water table. The results also demonstrate a potential of GPR for monitoring possible vapor phase effects of volatile hydrocarbons in the vadose zone as a function of time, and for detecting the effects of residual phase of hydrocarbons in the water saturated system. In addition, the results provide the basis for a strategy that has the potential to successfully detect and delineate residual LNAPL contamination in the water-saturated system at field sites where the conditions are similar to those simulated in the physcial models described herein.