• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.3
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• pp.90-99
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• 1994

To investigate the undrained shear strength characteristics of marine soils with high water content, high compressibility and weak bearing capacity, a series of undrained triaxial tests with pore pressure measurements on undisturbed and disturbed Banwol marine clay in normally consolidated and overconsolidated states is carried out. The results and main conclusions of this study are summarized as follows : 1 . When the consolidation pressure is increased, the maximum deviator stress of disturbed and undistubed clay in normally consolidated state is increased. Pore pressure parameters and internal friction angle of undisturbed clay are greater than those of disturbed clay. 2. The relationship between pore pressure and axial strain of undisturbed clay in normally consolidated state can be expressed as a hyperbolic function like stress-strain relation proposed by Kondner. 3. In the pore pressure-axial strain relation of disturbed clay in normally consolidated state, failure ratio R'f is greatly deviated in the range of 0.7~0.9 proposed by Christian and Desai. 4. For overconsolided clay, when overconsolidation ratio (OCR) is increased, normalized maximum deviator stress is increased and maximum pore pressure is decreased gradually. 5. Cohesion of overconsolidated clay is greater than that of nomally consolidated clay and internal friction angle slightly is decreased. 6. Pore pressure parameter at failure (Af) of overconsolidated clay is varied with OCR, Af becomes negative values with increment in OCR

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.70-73
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• 1997

Recycling of$\boxUl$ useful industrial waste is highly recommended by the government. Some geotechnical properties such as specific gravity, dry density, unconfined compressive strength, pH. compressibility, permeability were determined to evaluate the feasibility of waste lime use in the landfill as an admixture clay liner. Various types of environmental tests on waste lime were conducted to compare the results with the EPA requirements. Laboratory test results indicate that admixture soil(waste lime/decomposed granite soil) is a promising material its an admixture clay liner in the sanitary landfill.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.123-136
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• 2004

Terzaghi's one-dimensional consolidation theory has some important assumption, which can't be applicable to predict the behavior of soft clay ground. Especially, predictions using infinitesimal strain and linear material function related with permeability can give rise to mistake in comparison with the result of real behavior in site. For this reason, Gibson et al. established a rigorous formulation for the one-dimensional nonlinear finite strain consolidation theory, which can consider non-linearity of material function. But it is difficult to apply this theory to predict the behavior of common soft clay ground with vertical drain. In this study, consolidation model which can consider the vertical and horizontal flow of a fully saturated clay layer, self-weight of soil and nonlinear characteristics of compressibility and permeability are derived. Numerical analysis scheme, which can be applied to consolidation analysis by derived consolidation model in this study was developed. The characteristics of material function were examined using laboratory testing such as standard consolidation test, Rowe-cell test and modified consolidation test.

• Journal of the Korean GEO-environmental Society
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• v.7 no.3
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• pp.43-54
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• 2006

In this paper, the uniaxial, triaxial compression tests and consolidation tests on the clay sample substituted initial pore water for pollutant were performed to evaluate the change in geotechnical properties of the contaminated clay. The contaminant transport analysis on embankment type landfill using the MT3D model was also performed to evaluate the extent of transport and diffusion. There was tendency that strength, compressibility and permeability has increased with the increase in the concentration of NaCl solution. The increase in the strength and compressibility of sample saturated with leachate was higher than samples saturated with NaCl solution, but in the permeability coefficient was lower. As the result of contaminant transport analysis, the predicted concentration was in high with the increase in the initial concentration of $Cl^-$ ion and increased in a non-linear form. The transportation distance calculated with use of regression equation between the distance from contaminant source and the concentration of $Cl^-$ ion was increased with the increase in the initial concentration.

• Geomechanics and Engineering
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• v.12 no.4
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• pp.561-577
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• 2017

Vast parts of the east of Tabriz city have been covered by Baghmisheh formation marls. These marls can be classified into three types based on their color as identified in yellow, green, and gray marls. Many high-rise buildings and other projects were founded and now is constructing on these marls. Baghmisheh formation marls are classified as stiff soil to very weak rock, therefore they undergo considerable consolidation settlement under foundation loads. This study presents the physical properties and consolidation behavior of these marls. According to the XRD tests, major clay minerals of marls are Illite, Kaolinite, Montmorillonite and Chloride. Uniaxial compressive strength are 100-250, 300-480 and 500-560 kPa for yellow, green and gray marls, respectively. Consolidation and creep behavior of Baghmisheh marls investigated by using of one dimensional consolidation apparatus under stress level up to 5 MPa. The results indicate that yellow marls have high compressibility, settlement and deformation modules. Green marls have an intermediate compressibility and settlement and while gray marls have low compressibility and settlement and from the foundation point of view have high stability. According to the creep test results, all types of marls have not been entered to progressive creep phase up to pressure 5 MPa.

• Journal of the Korean GEO-environmental Society
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• v.12 no.6
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• pp.43-51
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• 2011

Marine clays are widely distributed in Korean eastern, western and southern coastal areas. Understanding engineering characteristics of the soft ground is very important, whenever civil structures are constructed in those coastal areas. It is because the ground is composed of highly compressible marine clay. In this paper, the physical and compression characteristics of Incheon, Mokpo, Gwangyang and Busan marine clay were analyzed and the characteristics between western and southern coastal marine clays were compared. For this, test results of 1,471 samples from 114 sites were used. As a result, Incheon clay showed the lowest plasticity and the highest unit weight due to influx of silt from the Yellow River and the turn of the tide of Incheon area. However, Gwangyang clay showed highly compressible characteristic due to extensive reclamation. On the other hand, Mokpo and Busan clay showed partially similar levels of characteristics. The compression index of Mokpo and Busan clay was high more than twice in comparison with Incheon clay and that of Gwangyang clay was higher than seventy percents in comparison with Mokpo and Busan clay.

• Geomechanics and Engineering
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• v.17 no.1
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• pp.69-79
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• 2019

This work presents an experimental study of the hydromechanical behavior of a natural swelling soil taken from Boumagueur region east of Algeria. Several pathological cases due to the soil shrinkage / swelling phenomenon were detected in this area. In a first part, the hydric behavior on drying-wetting paths was made, using the osmotic technics and saturated salts solutions to control suction. In The second part, using a new osmotic oedometer, the coupled behavior as a function of applied stresses and suction was investigated. It was shown that soil compressibility parameters was influenced by suction variations that an increase in suction is followed by a decrease in the virgin compression slope. On the other hand, the unloading slope of the oedometric curves was not obviously affected by the imposed suction. The decrease in suction strongly influences the apparent preconsolidation pressure, ie during swelling of the samples after wetting.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.361-368
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• 2000

In other to examine the compressibility characteristics of cohesive soils in the mouth of the Nakdong river, the oedometer tests were peformed on undisturbed and reconstituted samples obtained by continuous boring typically at 3 different sites. It is meaningful to compare the consolidation behavior of natural clays with a reference state because the natural clays are depending on the stress history, sedimentary environment and geological history. In this study, the insitu state of the Pusan clays was investigated using the concepts of ISL(Nagaraj, 2000) and ICL and SCL(Burland, 1990). And for the purpose of confirming the existence of the underconsolidated clays, a standpipe type piezometer test and a dissipation test by piezocone were performed at their sites. Consequently, the Pusan clays were evaluated as normally consolidated clays.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.982-989
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• 2005

In this study, a series of laboratory tests based on 'Unit-cell concept' are performed to investigate improvement characteristics of clay ground in sand compaction pile method. Settlement reduction characteristics of composite ground and improvement characteristics of clay part could be qualified. In these procedure, the new strain-compression index($C_{\epsilon}$) of composite ground are adopted to show compressibility of composite ground according to the area replacement ratio, which is similar to the compression index($C_c$) in pure clay ground. Also, using normalization of reduction of water content in composite ground to the initial water content, improvement characteristics of clay part are investigated.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.3
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• pp.1-7
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• 2009

Talc as a coating pigment has been developed in order to replace GCC and clay for matte grade and has received much attention due to various advantages including good gravure printability. In order to elucidate the effects of talc on gravure printability, model papers were produced with three kinds of coating talc whose particle size and brightness are different. Physical properties related to surface and structure and the gravure printability of the sample were tested. Coating color with talc showed lower viscosity than that with clay. For both matte and art grades, talc tended to give lower gloss than day. The smaller the particle size of talc, the better properties in the coating color viscosity and water retention. When the particle size of talc was small enough, the surface roughness of the coated paper produced with talc was similar to that with clay while larger talcs produced rougher surface than clay. On top of that, application of talc improved compressibility and gravure printability of coated paper.