• Geomechanics and Engineering
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• v.36 no.6
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• pp.589-599
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• 2024

Dispersion occurs when clay soil disperses under specific conditions and is rapidly washed away. While there are numerous methods for rectifying it, they are neither cost nor time-effective. The current study used metakaolin and zeolite to improve heavily dispersive clay soil either separately or in combination at 0%, 2%, 4%, 6%, and 8% of the soil weight. After 7 days of curing, the samples were tested to determine the extent of change in the dispersion potential, as well as the improvement of the geotechnical properties of the soil. The results indicated that the addition of 2% zeolite with 6% to 8% metakaolin decreased the dispersion potential considerably. Double hydrometry test findings revealed that the dispersion potential decreased by almost 70% and entered the non-dispersive group; the crumb test also revealed this. Atterberg limits testing indicated a decrease in the plasticity index which reduced the flexibility of the samples. The greatest decrease in PI (67.5%) was achieved with the addition of 8% zeolite plus 8% metakaolin to the soil. The results of density tests revealed that a decrease in the optimal moisture content increased the maximum dry density of soil. This increase in density was a response to the high reactivity of metakaolin with calcium hydroxide and the formation of calcium hydroxide hydrate gel. This eventually caused an increase in the unconfined compressive strength, the greatest increase in strength of about 1.8-fold was observed with a combination of 2% zeolite and 6% metakaolin compared to the unmodified sample.

• Geomechanics and Engineering
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• v.15 no.6
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• pp.1135-1141
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• 2018

Volume changes of soils induced by inorganic acids cause severe foundation and superstructure failures in industrial buildings. This study aimed to assess the potential of fly ash to control volume changes in soils under acidic environment. Two soils such as black cotton soil predominant with montmorillonite and kaolin clay predominant with kaolinite were used for the present investigation. Both soils exhibited an increase in swelling subjected to phosphoric acid contamination. Ion exchange reactions and mineralogical transformations lead to an increase in swelling and a decrease in compressibility in black cotton soil, whereas phosphate adsorption and mineral dissolution lead to an increase in swelling and compressibility in case of kaolin clay. Different percentages of Class F fly ash obtained from Ramagundam national thermal power station were used for soil treatment. Fly ash treatment leads to significant reduction in swelling and compressibility, which is attributed to the formation of aluminum phosphate cements in the presence of phosphoric acid.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.657-664
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• 2000

Weak and soft compressible clay deposits are commonly found in natural subgrade soils. These Soils need to be stabilized for using the subbase materials of highway constructions. This paper presents that a chemical treatment using chemical additives comprised of sulfate(SO$_4$) and chloride(Cl) is evaluated for stabilizing soft clay deposits and lime. The physical and mechanical characteristics of soil-lime and additives are described by means of a laboratory study. The study results indicate that the presence of chlorides encouraged the efficiency of lime stabilization, and the use of calcium chloride with quicklime is the best additive for improving soil behavior. The treated soil with lime-calcium chloride can have the adaptability to the subbase materials of highway constructions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.390-393
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• 2002

Many researchers have studied for the barrier liner in the landfill that is mixed with clay mineral, native soils and solidified agent. However, they have a littel but problems for safety construction and maintenance as a bottom liner systems in the landfill. In this paper the authors studied the effects on hydraulic conductivity by electric-chemical ion-exchange agent that is a soil stabilization agent(Sulphonated Oil), The application of the soil stabilization agent to meet the hydraulic conductivity of clay liner in landfill is possible if the additive quantity and a proper reaction time is determined relevantly in the laboratory test.

• Geomechanics and Engineering
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• v.5 no.6
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• pp.565-574
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• 2013

Extensive study was carried out on Clay expansive soil. This soil was silty clay and can be classified as CH. The degree of expansion was found to range from low to medium depending on the free swell and swell pressure tests. The research investigated the effect of using cement dust on swelling potential, Atterberg Limit, linear shrinkage, and mineralogical composition of expansive soil. The results showed that the swelling potential, plasticity index, linear shrinkage, and clay minerals decrease with increasing cement dust percentage. The cement dust accumulates in huge amounts as a side product in cement factories, and the disposal of this fine dust is very difficult and poses an environmental threat.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.3
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• pp.141-145
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• 1974

Adsorption experiments were carried out with several clay minerals and PCP hexane solution in order to clarify the status of adsorbed PCP on the clay surface. The amount of PCP adsorption on clay minerals was much greater in the clay-hexane system than in the clay water system. Among the clay minerals, allophane and imogolite ($SiO_2/Al_2O_3$ ratio of about 1) were the most efficient adsorbents of PCP. The PCP adsorption from hexane solution was greatly hindered by the presence of water, suggesting the occurrence of adsorption by a dipole-dipole interaction. PCP adsorption is dependent upon the nature of the clay surface and the exchangeable cations rather than the total surface area.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.301-304
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• 1983

Effects of the clay content on soil chemical properties and rice productivity were studied to evaluate the optimum range of clay content from 42 NPK trials conducted by the provincial ORD in 1979. Nutrients content and CEC of the paddy soils were increased with the increase of clay content in paddy soils. Rice yields without NPK application showed a positive linear regression with respect to surface clay content in the paddies, while the relationship between rice yield and clay content with optimun fertilization showed a curvilinear regression, which indicated the maximum yield was observed in loam soils. However, the yield of rice was not significantly different in the range of clay content from 14 to 38%. It implies that the clay content more than 15% may be secondary constraint in determining the soil productivity.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.09a
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• pp.61-69
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• 2000

It is not easy to find a good soil condition due to the shortage of suitable land for construction work. The earth structure and buildings can be constructed over the soft soil. The soft soil must be treated either using the reinforcement element or dewatering. Most of land reclamation projects are being implemented along the south coast or west coast of the Korean Peninsula. The soils in these areas are covered with the soft marine clay, so soil and site improvement is the most important things to do. Pile foundation at the bottom of embankment can be constructed either in the soft ground or in the soil contaminated area. The purpose of this research is to develop "geogrid-reinforced piled embankment method" to prevent the differential settlement and increase the bearing capacity of soil. In this study, the effectiveness of the geogrid-reinforcement was studied by varying the space between piles and reinforcement conditions. Also, the geotechnical engineering properties of the embankment material and foundation soil were determined through the laboratory tests as well as the field tests. As a result, the site that the pile-spacing S = 3b with geogrid reinforcement is the most effective to reduce the differential settlement and increase load bearing capacity.

• Geotechnical Engineering
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• v.12 no.2
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• pp.115-132
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• 1996

Several soil improvement methods are applied to stabilize soft ground. But, their improvement effects are known to be reduced in view of strength and durability under poor conditions such as marine clay and the ground with the flow of groundwater. The soil improvement method is generally classified as mixing(high pressure) type and injection type, and in this study, for successflll'applications of gelling methods, first in case that mixing method with cement is applied to marine clay, the causes of strength inferiority of treated soil are analyzed, and the effectiveness of improvement is studied, second in case that injection method with water-glass chemical grouts is applied to the ground with the flow of groundwater, soil improvement effects and durability of grouted soil are studied.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.4
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• pp.1-8
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• 2000

This study is conducted to evaluate the effects of root restriction on growth of maple(Acer palmatum Thumb.). Tow types of container such as clay pot(CP), root control bag(RCB) were used to restrict maple's root and each type of container was divided into 5 sizes. The containers with plants were buried just below the soil level and maples planted directly in the soil (nonrestricted root treatment) were included as comparison. Data were collected on dry weight of leaf, trunk, thick root, rootlet and soil water potential. We have analyzed, simple linear regression, Pearson's Correlation analysis, Duncan's multiple rang test, and Covariance Analysis using SAS statistical software. The results of analysis based on these data are as follows; 1. Total dry weight of maple in CP was significantly larger than in RCB. 2. Difference in growth reduction by the kinds of containers was induced by different hydraulic diffusion ratios between container and soil. Difference in growth reduction by the size of container was induced by the difference density of rootlet and soil moisture contents in the container. 4. Commercial products of root control of root control bag appeared not proper for countries in which fluctuation of rainfall is severe. Because maples in RCB were restricted by excess soil water in the rainy season, or by lack of soil water in the dray season.