• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.117-126
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• 2005

The chemical property analysis on the deposited clay using scanning electron microscope and energy dispersive x-ray spectrometer were performed. Also, the triaxial compression tests and consolidation tests using NaCl aqueous solution and leachate as substitute pore (or saturated) water in samples were carried out to find out the behaviour characteristics of strength and deformation of contaminated deposited clay. from the chemical composition analysis results of clay samples, the magnitudes of composition ratio were revealed in the order of O, C, Si, Al, and Fe. Of these, why the ratio of carbon appeared to be large is estimated as due to the increase of the phyto-planktons after the construction of tide embankment. In the triaxial compression test and consolidation test results, the shear strength and compression properties have increased with the increase in concentration of contaminant (NaCl). This phenomenon is considered as to be caused by the changes of soil structure to flocculent structure owing to the decrease in the thickness of diffuse double layer in proportion to increase in the concentration of electrolyte.

• Journal of Conservation Science
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• v.27 no.4
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• pp.451-458
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• 2011

This study aims at identifying wall painting production technique of Songsanri No. 6 tomb based on optical examination and scientific analysis along with the investigation of written records of ancient wall paintings. The result displays that bricks with mortar were used for the construction of the wall, and masonry joint were made of lime, sand and gypsum. The surface of brick were plastered with black and thereafter with white lime. Finely sifted clay on the top of the white surface, were applied not with plasterer's trowel but with a brush for making ground surface. The clay are mineral particles smaller than $30{\mu}m$ of silt. The wall paintings of Sonsanri No. 6 is the only example of making ground layer with clay for painting of Sasindo (literally four heavenly animals painting) among remaining wall paintings of ancient tombs. The historical value of the painting should be attributed not only in terms that it displays a rare production techniques which were never discovered in any other paintings in Korea and Asia, but also it might had been uncompleted when the tomb were closed, even though it considers the fact that the wall painting were discovered in damaged condition in 1933.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.179-184
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• 2008

Silt or clay alluvium fully saturated with water generally shows low resistivity. Sometimes it is believe that the low resistivity layer is considered as good aquifer but this makes problems in the development of groundwater. To overcome this problem, we adopted induced-polarization(IP) method with resistivity method. Laboratory experiments and resistivity/IP field surveys with non-polarization electrodes were conducted for the study. Laboratory experiments shows that the increase of clay contents in the sample mixed with sand and clay give low resistivity and high chargeability. We used this experiment results in the interpretation of resistivity/IP field data which were obtained in riverbank filtration. Finally, the layer which has low resistivity and chargeabilty would be regarded as a good aquifer for the development of groundwater intake.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.336-344
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• 2017

The soil water characteristics curve (SWCC) represents the relation between soil water potential and soil water content. The shape and range of SWCC according to the relation could vary depending on soil characteristics. The objective of the study was to estimate SWCC depending on soil types and layers and to analyze the trend among them. To accomplish this goal, the unsaturated three soils were considered: silty clay loam, loam, and sandy loam soils. Weighable lysimeters were used for exactly measuring soil water content and soil water potential. Two fitting models, van Genuchten and Campbell, were applied. Two models entirely fitted well the measured SWCC, indicating low RMSE and high $R^2$ values. However, the large difference between the measured and the estimated was found at the 30 cm layer of the silty clay loam soil, and the gap was wider as soil water potential increased. In addition, the non-linear decrease of soil water content according to the increase of soil water potential tended to be more distinct in the sandy loam soil and at the 10 cm layer than in the silty clay loam soil and at the lower layers. These might be seen due to the various factors such as not only pore size distribution, but also cracks by high clay content and plow pan layers by compaction. This study clearly showed difficulty in the estimation of SWCC by such kind of factors.

• Economic and Environmental Geology
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• v.34 no.2
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• pp.193-204
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• 2001

A geophysical survey was undertaken at Wiri area, Andong, to delineate subsurface structure and reveal the fault zone nearby which heaving of road and subsidence of slope occurred in 1997, especially in the heavy rainy season. Electrical resistivity methods of dipole-dipole array profiling and Schlumberger array sounding and seismic methods of refraction and reflection were performed for the mapping of clay layer, which was interpreted to be the major factor among the reasons of slope deformation. The clay layer was characterized by lower electrical resistivities (< $100{\Omega}{\cdot}m$) and lower seismic velocities (<400 m/s), respectively. The results of electrical and seismic surveys showed that subsidence of slope was probably associated with sliding of wet clay on 18SW/NNW trending fault plane, while heaving of road was probably caused by upward movement of the wet clay through subvertical NNE trending fault.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.330-337
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• 2005

This study was investigated to elucidate the pesticide mobility in three different soil textures(Heongseong sandy loam; Chuncheon, loam; Taeback, silty clay loam) and four different gravel contents(0, 20, 40, 60%) of Taebaek soil using soil column. Carbofuran, which ranks the highest water solubility among 7 pesticides(carbendazim, carbofuran, chlorpyrifos, cypermethrin, dimethomorph, diniconazole and endosulfan) was defected over 87% in leachate samples within all soil types from early sampling time. Amount of 5 residual pesticides excluding carbendazim and carbofuran were ordered silty clay loam > loam > sandy loam, indicating pesticide residues are related to percentage of clay contents in soils. Comparing the amount of residual pesticides in soil column(upper, middle and lower layer), 6 pesticides apart from carbofuran were found in the range of $50{\sim}92%$ on the upper layer of silty clay loam and loam. Mobility of pesticides either in soil or leachate samples is dependant on water solubility of pesticide and clay content of soil. The results obtained from four different gravel contents of Tacback soil were similar to the results of three different soil textures. Also it was found that more the gravel contents, faster the flow velocity of leachate water. These results possibly provide an idea to select proper pesticides and to reduce soil and water contamination at alpine and sloped-land.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.223-227
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• 1998

The objectives of this study were to find the sprouting condition and to establish the optimum production methods of plug seedlings in yacon (Polymnia sonchifolia Poepp. & Endl.). The sprouting ratio was greatest at $30\pm 1^{\circ}C$ at 20 days after planting. Crowns with single buds were more effective than those with two or more buds for sprouting, which might be due to the apical dominance. Planting the shoots separated from crown after sprouting in the single- and double-layer polyethylene-covered greenhouses reduced seedling period with 25% and 50%, respectively. Planting the shoots after sprouting was more effective than planting the crown buds. Double-layer polyethylene-covered green-house was good for plug seedling production than open field or single-layer polyethylene-covered greenhouse. The bed soils composed of clay loam : compost or sand : compost (1:l=v:v) were more effective to produce plug seedlings than only clay loam, sand or compost. Seedlings could be produced at 30 days after planting in our studies.

• The Journal of the Acoustical Society of Korea
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• v.20 no.4
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• pp.71-80
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• 2001

In order to consider the sediment layer's effect to total acoustic field, we composed a 3 layered fluid model of 2 sediment layers by adding an additional layer to the Pekeris model and found solutions by using Green's function, boundary conditions and Sommerfeld radiation condition. The modes were divided into discrete modes and virtual modes, and confirmed that the characteristic equation to find discrete modes was same as that of Tolstoy and Clay for normal modes. Also, we confirmed that under similar conditions the 3 layered model showed same results as that of Pekeris model. We believe this 3 layered model can be used to study the sediment's effect on the virtual mode of near field.

• Korean Journal of Environmental Agriculture
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• v.3 no.2
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• pp.50-54
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• 1984

For the development of slow releasing K-fertilizer, K-ion exchanged montmorillonite was evaluated and characterized by layer charge determination with n-alkylammonium method. By this method it was possible to discern inhomogenous charge distribution within the crystals and to estimate the upper and lower limit of the layer charge(layer charge limit for Young-il bentonite in Korea: ${\xi}=0.39-0.28$ $e/(SiAl)_4O_{10}$, ${\xi}=0.34$) and the mean value of interlayer cation exchange capacity of 0.915meq/100g.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.349-356
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• 2003

Almost every material of PVD (Prefabricated Vertical Drain) has the fatal problem on the condition - the length must shorten with the settlement of the surrounding grounds - which all PVDs must satisfy. Kinking deformation by buckling of PVD due to consolidation settlement Is discussed in this paper. A new testing device to clarify the deformation of PVD under consolidation of surrounding clay was developed and the fiber drain and a PVD made of plastics were compared under the same condition of consolidation using natural clay specimens. The results are also shown in this paper.