• Food Science and Biotechnology
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• v.14 no.1
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• pp.112-116
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• 2005

Composite films were prepared with soy protein isolate (SPI) and various clay minerals by casting from polymer and clay water suspension. Effects of clay minerals on film thickness, moisture content (MC), tensile strength (TS), elongation at break (E), water vapor permeability (WVP), and water solubility (WS) were tested. Properties including thickness, surface smoothness, and homogeneity of films prepared with organically modified montmorillonite (O-MMT), Wamok clay (W-clay), bentonite, talc powder, and zeolite were comparable to those of control SPI films. TS increased significantly (p<0.05) in films prepared with O-MMT and bentonite, while WVP decreased significantly (p<0.05) in bentonite-added films. WS of most nanocomposite films decreased significantly (p<0.05).

• Journal of the Korean Geotechnical Society
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• v.32 no.10
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• pp.5-15
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• 2016

This study investigated both water content and penetration resistance of small cone of various clay soils that were made of Kaolinite and Bentonite with different mixing ratios and compared the results with those of the existing dynamic (Casagrande test) and static (fall cone test) tests directly. The comparison showed that the water content at the inflection point on a curve of water content and penetration resistance was very similar to the liquid limit from a fall cone test. The penetration resistance of small cone at the inflection point was 0.2 kPa, and it was ascertained that the water content at the inflection point represents a liquid limit of clay soils. From the study results, it was found that the penetration resistance of 0.2 kPa with the small cone can be an indicator of the liquid limit of clay soils in practice. Finally a test procedure to measure the liquid limit of clay soil based on a penetration resistance of small cone was proposed.

• Geotechnical Engineering
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• v.13 no.1
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• pp.159-168
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• 1997

In order to investigate the effect of parameters such as orientation and surface roughness of a reinforcing material as well as the water content of the clay matrix on the stress-strain and failure behavior of reinforced clay, uniaxial compression tests were performed on clay samples reinforced with a steel inclusion Test results showed that the increase or decrease in strength of reinforced clay samples was found to depend on the orientation of a steel inclusion as well as water content of clay samples. The possible weakening mechanism induced by reinforcement in clay samples was related to the development of cracks along the tips of interface between steel inclusion and clay matrix. A theoretical interpretation of failure behavior of reinforced clay was made by using fracture mechanics theory, and the experimental results were compared with the theoretical predictions. The predicted crack propagation direction obtained from fracture criteria for a material containing a closed crack with friction agreed reasonably well with the measured values obtained from tests.

• 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.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.63-73
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• 2003

The settling of the dredged soil may vary with mineral composition, grain size distribution, initial water content and salt concentration of suspension of the site. A series of settling column test was performed to investigate the behaviour of solid suspension material from dredging and reclamation. Settling mode was divided into four types from the observation of interface and settling curves of clay minerals and marine clay samples, and the relationship charts of salt concentration and the initial water content were established to use in the dredging operation with any salt concentration. The critical initial water content which was defined as a threshold of zone settling and the consolidation settling was varied with salt concentration of water and was proportional to the plasticity of soil in sea water.

• Geomechanics and Engineering
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• v.12 no.4
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• pp.707-721
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• 2017

The objective of this paper is to experimentally study the consolidation of saturated silty clay subjected to repeated heating-cooling cycles using a modified temperature-controlled triaxial apparatus. Focus is placed on the influence of the water content, confining pressure, and magnitudes and number of thermal loading cycles. The experimental results show that the thermally induced pore pressure increases with increasing water content and magnitude of thermal loading in undrained conditions. After isothermal consolidation at an elevated temperature, the pore pressure continues to decrease and gradually falls below zero during undrained cooling, and the maximum negative pore pressure increases as the water content decreases or the magnitude of thermal loading increases. During isothermal consolidation at ambient temperature after one heating-cooling cycle, the pore pressure begins to rise due to water absorption and finally stabilizes at approximately zero. As the number of thermal loading cycles increases, the thermally induced pore pressure shows a degrading trend, which seems to be more apparent under a higher confining pressure. Overall, the specimens tested show an obvious volume reduction at the completion of a series of heating-cooling cycles, indicating a notable irreversible thermal consolidation deformation.

• Journal of Ocean Engineering and Technology
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• v.22 no.2
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• pp.42-49
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• 2008

Recently many countries have become interested in the development of cold or arctic regions. The construction of engineered structures in those regions demands an understanding of the deformation characteristics of frozen soil. However, an understanding of frozen soil behavior poses difficult problems owing to the complex interaction between the soil particles and the ice matrix. In this research, a series of laboratory tests was performed to investigate the variations in the unconfined compression strength and split tensile strength of weathered granite soil and mixed soil (standard sand and kaolinite) in 15 degrees below zero environments. In the frozen soil tests, specimens were prepared with various water and clay contents, and then the interrelationships between four factors (water content, clay content, unconfined compression strength, split tensile strength) were analyzed. The test results were summarized as follows; as the water content was increased, the unconfined compressive and split tensile strengths also increased in frozen soil. However as the clay content was increased, the unconfined compressive and split tensile strengths were lowered. In the case of frozen soil that contained little clay content, the strength decreased rapidly in mixed soil (standard sand and kaolinite) when the frozen specimen was broken. On the other hand, in the cases of mixed soil that contained a high clay content and weathered granite soil, the strength decreased relatively slowly.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.93-107
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• 2005

The estuary of Nakdong River area including Noksan industrial complex and Busan New Port is composed of thick unconsolidified sediments containing abundant clay, and thus is a potential hazardous area of ground subsidence. We analyzed mineral compositions and geotechnical properties of the clay sediments that sampled from 4 boreholes of the area, and examined vertical variations and their correlations. The results showed correlations between some mineral constituents and geotechnical properties of clay sediments. A positive correlation showed between quartz content and wet unit weight, whereas a negative correlation showed between quartz content and liquid limit. Feldspar content and water content showed a negative correlation, whereas content of clay minerals and liquid limit showed a positive correlation. And also, there is a negative correlation between content of clay minerals and wet unit weight. Correlation equations are obtained from the multiple regression analyses among plastic index, content of clay mineral, smectite and clay fraction.

• Journal of the Korean Geotechnical Society
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• v.37 no.8
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• pp.5-13
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• 2021

Liquefaction behaviors of two natural silty samples containing fines including clay of 50% or more (Sample No.1 was silt 44.1% and clay 8.8%, sample No.2 was silt 57.2% and clay 12.4%) were examined by a cyclic triaxial test. According to the results on samples containing 50% or more of fine particles, an increase in the fine content decreases the liquefaction resistance of the sample. In other words, when the fine content increases, the liquefaction state of sample is reached with a small number of cyclic loads. In the relationship between the excess pore water pressure ratio and the number of cycles, the slope of the excess pore water pressure ratio increases more steeply as the fine content increases. As a result of analyzing the liquefaction behavior of the two silts with the content of clay contained in the fines, liquefaction occurred more easily in the No.2 silt with high clay content. This result shows that the clay contained in the fines affects the liquefaction behavior of the silt.

• Geomechanics and Engineering
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• v.27 no.6
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• pp.615-626
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• 2021

The main objective of this study is to present a fast and reliable approach to predict the swelling potential of clay-bearing rocks. Investigations showed that there is a good correlation between the swelling potential of a rock and its desire to absorb water due to its clay content which could be measured using the "Contact Angle" test as one of the most common ways to determine the wettability. In this test, the angle between a water drop and the flat rock surface on which it rests is measured. The present method is very fast and returns repeatable results and requires minimal sample preparation. Only having a saw-cut surface of a sample with any shape is all one needs to perform this test. The logic behind this approach is that the swelling potential of a rock is a function of its mineral content and molecular structure, which are not only distributed in the bulk of the sample but also reflected on its surface. Therefore, to evaluate swelling behavior, it is not necessary to wait for a sample to get wet all the way to its "internal structure" (which, due to the low permeability of clay-bearing rocks, is very slow and time-consuming). Instead, one can have a good sense of swelling potential by studying its surface. Parametric studies on the effect of moisture content, porosity, and surface roughness on the contact angle measurements showed that using a saw-cut oven-dried sample is a convenient way to evaluate the swelling potential by this method.