• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.322-329
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• 2006

On the way of construction in harbor area, scourin problems took place slowly failure of embankment in the beginning of construction in sites. For studying on the scouring properties during revetment construction in silty sand soil layers, this paper is carried out on lessons of case studies of numerical seepage analysis, scouring countermeasures in dredged landfill area.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.14-19
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• 2009

To obtain the basic data on reclaimed tideland soils, 90 soil samples were collected from 9 tideland reclamation project areas in Korea. The soils consisted of clay (2.0 to 35.0 percents), silt (2.0 to 80.0 percents), and sand (8.0 to 95.0 percents), and were dominantly classified sandy loam and silty loam. The soils had pH of 4.5 to 9.1, organic matter of 0.50 to $19.20g\;kg^{-1}$, total nitrogen of 4 to $1,159mg\;kg^{-1}$, and avaliable phosphorus (as $P2_O_5$) of 3.5 to $147.7mg\;kg^{-1}$. The electrical conductivity in soil saturation-paste extracts (ECe) ranged between $0.62dS\;m^{-1}$ and $31.60dS\;m^{-1}$ and the concentrations of sodium and magnesium ions were higher than those of potassium and calcium ions. The magnitude of the ECe was as low as that of normal level in Nam-Po, Pu-Sa, and Kye-Hwa reclamation project areas having sandy loam texture, but was as high as that of normal level saline-sodic level in Nam-Yang and So-Po reclamation project areas having silty loam texture even though the soils were cultivated more than 10 years as a paddy. Some part of Saemangeum area was surveyed and soil textures were various; some were silt loam and some were sandy loam. The ECe values were very high in topsoil and subsoil.

• Journal of the Korean GEO-environmental Society
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• v.24 no.11
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• pp.41-49
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• 2023

In this study, we analyzed the settlement characteristics of rockfill embankments mixed with soil by confirming the physical properties of soil materials mixed with silty materials and analyzing the compression characteristics of gravel materials according to the mixing ratio of soil materials. For this, we mixed silty materials into sandy soil to analyze the compression characteristics of soil materials, and we constructed a foundation by mixing various ratios of soil into rockfill materials with a particle distribution similar to that of river gravel, and conducted a one-dimensional compression experiment using a medium-sized chamber. As a result of the experiment, in the case of mixed soil materials, the Transition Fine Content (TFC) appeared in the range of 21~26% depending on the load condition, and in the case of rockfill materials mixed with soil, as the void filling ratio of soil in gravel samples increases, both total compression and creep compression decreases, but after a 50% mixing ratio, the settlement of amount increases again.

• Geomechanics and Engineering
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• v.36 no.2
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• pp.145-156
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• 2024

The mechanical properties of the concrete-frozen soil interface play a significant role in the stability and service performance of construction projects in cold regions. Current research mainly focuses on the precast concrete-frozen soil interface, with limited consideration for the more realistic cast-in-place concrete-frozen soil interface. The two construction methods result in completely different contact surface morphologies and exhibit significant differences in mechanical properties. Therefore, this study selects silty clay as the research object and conducts direct shear tests on the concrete-frozen soil interface under conditions of initial water content ranging from 12% to 24%, normal stress from 50 kPa to 300 kPa, and freezing temperature of -3℃. The results indicate that (1) both interface shear stress-displacement curves can be divided into three stages: rapid growth of shear stress, softening of shear stress after peak, and residual stability; (2) the peak strength of both interfaces increases initially and then decreases with an increase in water content, while residual strength is relatively less affected by water content; (3) peak strength and residual strength are linearly positively correlated with normal stress, and the strength of ice bonding is less affected by normal stress; (4) the mechanical properties of the cast-in-place concrete-frozen soil interface are significantly better than those of the precast concrete-frozen soil interface. However, when the water content is high, the former's mechanical performance deteriorates much more than the latter, leading to severe strength loss. Therefore, in practical engineering, cast-in-place concrete construction is preferred in cases of higher negative temperatures and lower water content, while precast concrete construction is considered in cases of lower negative temperatures and higher water content. This study provides reference for the construction of frozen soil-structure interface in cold regions and basic data support for improving the stability and service performance of cold region engineering.

• Geomechanics and Engineering
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• v.31 no.2
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• pp.167-181
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• 2022

Soil liquefaction has been one of the most important concerns in geotechnical earthquake engineering in recent years, due to its damages to structures and its destructive effects. The cyclic liquefaction of silty sands, in particular, remains of great interest for both research and application. Although many factors are known that affect the liquefaction resistance of sands, the effect of fine grain content is perhaps one of the most studied and still controversial. In this study, 48 deformation-controlled cyclic simple shear tests were performed on BS and CS silt samples mixed with 5%, 15% and 30% by weight of Krk085, Krk042 and Krk025 sands in constant-volume conditions to determine the liquefaction potential of silty sands. The tests were carried out at 30% and 50% relative density and under 100 kPa effective stress. The results revealed that the liquefaction potential of silty sand increases with increasing average particle size ratio (D_50sand / d_50silt) of the mixture for a fixed silt content. Furthermore, for identical base sand, the liquefaction potentials of coarse grained sands increase with increasing silt content, while the respective potentials of fine grained sands generally decrease. However, this situation may vary depending on the silt grain structure and is affected by the nature of the fine grains. In addition, the variation of the void ratio interval was shown to provide a good intuition in determining the liquefaction potentials of silty sands, while the intergranular void ratio alone does not constitute a criterion for determining the liquefaction potentials of silty sands.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.4
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• pp.340-349
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• 1995

Effects of the zeolite particle size on the soil chemical properties and on rice growth was investigated on the pot with the loamy sand (Sadu series) and silty clay loam(Paju series) soils. All the zeolite treatments brought the increase of unhulled grain yield on the both loamy sand and silty clay loam soils. Unhulled grain yield increased with increasing the amount of zeolite applied and with decreasing the amount of particle size of zeolite applied on both soils. Unhulled grain yield increased significantly by 11.1% (22.79g/head) with 2ton/10a of smaller than $106{\mu}m$ size zeolite on the loamy sand soil and on the silty clay loam soil, yield increased by 9.3% (24.98g/head) with 1.5ton/10a of smaller than $106{\mu}m$ size zeolite. CEC, pH and contents of exchangeable cations of the soil after experiment were raised by increasing the amount of zeolite and also by decreasing the particle size of zeolite at both soil. At the heading stage, the zeolite treatments improved the growth of rice plant compared to control. The nutrient contents(T-N, Ca, Mg, K, Na), except phosphorus, in the rice plant grown on the zeolite treated soils were higher than control plot.

• Journal of the Korean Geotechnical Society
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• v.32 no.6
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• pp.17-26
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• 2016

Characteristic behaviors of geo-structure during freezing and thawing process have to be understood based on fundamental knowledge on phase change in porous soil and interaction between soil and structure. Inversion analysis using published one-dimensional soil freezing tests was conducted to suggest a mechanical model to consider an effect of the ice saturation on Young's modulus. Silty soil was more sensitive to temperature than weathered granite soil and sand, and weathered granite soil was more affected by initial water saturation in stiffness decrease than silty soil. Numerical simulations on chilled gas pipeline showed that shielding effect from surrounding frozen zone around the pipe decreases impact from external load onto the pipe. And a pipe installed in sand backfill showed more heaving due to relatively low stiffness of sand during freezing than that of surrounding in-situ weather granite soil. However, it had more stable stress condition due to effective stress redistribution from external load.

• Journal of Environmental Science International
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• v.4 no.4
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• pp.379-386
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• 1995

Permethrin [3-phenox yben zyl(1RS)-cis,tans-3-(2,2-dichloroviny1)-2,2- dimethylcyclopropane carboxylate] insecticides were selected to study adsorption and leaching potentials related to pollution on Commerce silty clay loam soil near Baton Rouge, Louisiana, USA. GLC-ECD chromatogram of permethrin included 32.5 % of cis-pemehin and 67.4 % of trans-permethrin. Extraction efficiencies of is and trmu-pemetun were 92.5 % and 92.3 % in fortified water, respectively and 85.9 % and 88.8 % in fortified soil, respectively. At a 1:10 moi]/water ratio,the Koc values for sis and fan isomers of permethrin were 938 and 877, respectively. Leaching of permethrin was evaluated in soil columns$(5.4 cm i.d. \times 26 cm length)$. Total recoveries of the permethrin applied to the soil column were $84.5\pm3.1%$. When the soil columns were leached with three pore volumes of water, the distributions of cis-permethrin leached were 6.10 % and 0.07 % of amount applied in the untreated zone soil and leachate water, respectively Trans-pemethrin distributions were 5.20 % in the untreated zone soil and 0.05 % in leachate water. Cis and trans-pemethrin was strongly adsorbed to soil. The results of the study showed the strong relationship between adsorption and leaching. Cis and trans-permethrin to be leached into the groundwater in soils with shallow aquifers were suggested a low leaching potential.

• Journal of the Korean Geotechnical Society
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• v.31 no.1
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• pp.25-35
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• 2015

Penetration resistance of bucket foundations with skirt wall in the silty sand of the western coast of Korea was analyzed by centrifuge modelling. The penetration resistance is induced when the bucket foundations are jacked into the soil without suction, and is directly related to the self-weight penetration depth. The procedure by Houlsby and Byrne (2005), which takes into account the effect of stress increase by frictional resistance of skirt wall, was utilized to generate the penetration resistance similar to the experimental results. This paper describes the methods by which major parameters such as lateral earth pressure coefficient and friction angle between the skirt wall and the soil are evaluated. The effect of changes in these parameters on the predictions is analyzed. Also, observed soil behaviour during jacking penetration is investigated.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.88-97
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• 2009

This study was conducted to obtain the basic information to increase the practical use of soil survey data through the subdividing of lava shapes with soil sequences due to different elevations in Jeju. The numbers of soil series of lava topography had occupied many of whole soil series in Jeju. When its topography subdivide, it give more detailed soil information. The obtained results are as follows; The lava topography to subdivide lava topography were studied with 38 soil series according to elevation in Jeju. Division of elevation are less than 50m, 50m to 200m, and 200m to 400m and more than 400m. Name the depending on elevation, less than 50m is called lower part of lava, 50m to 200m is called middle part of lava, and 200m to 400m and more than 400m are called upper part of lava. The characteristics of lava subdivide are as follows; soil family texture of lower part of lava is fine silty to clayey, drainage classes are various, average of available soil depth is 75.3cm, average of gravely contents are 11.6%, average of slopeness is 7.2%, limiting factor are various and soil order are various. soil family texture of middle part of lava is fine silty to coarse silty, drainage classes are well to very well, average of available soil depth is 65.9cm, average of gravely contents are 14.7%, average of slopeness is 11.3%, limiting factor are ashy and soil order are Andisols and Inceptisols. Soil family texture of upper part of lave is fine silty, drainage classes are well, average of available soil depth is 72.8cm, average of gravely contents are 16.0%, average of slopeness is 14.9%, limiting factor are ashy and skeletal, and order are Andisols.