• Geomechanics and Engineering
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• 제12권4호
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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.

• 한국산업융합학회 논문집
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• 제7권1호
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• pp.83-89
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• 2004

The analysis about consolidation characteristic in soft clay has been depending one-dimension consolidation analysis. but, drain and undrain zone are explicated as homogeneous by consolidation behavior following consoli- dated settlementsoft in soft clay. 1) Established sand drain in soft clay in many types, and measured water content, unconfined compression strength, vertical stress, horizontal stress, vertical settlement, pore water pressure. 2) Arranged the result from the test and numerically explicated effective stress, total stress, and effective stress path at the drain and undrain zone. 3) We also analyzed and comparied elastic and elastic-plastic in soft clay using measured data. The result analyzed does not approach to a special theory, but, it is well in accord with the result of other investigator's study in the same condition.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.395-398
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• 2003

Geosynthetic Clay Liners(GCLs) have been widely used as hydraulic barrier in landfills and remediation projects of contaminated sites. The aim of this research is to modify GCLs for effective removal of contaminants. We perform the free swell test, hydraulic conductivity test, and contaminants (TCE, hexavalent chromium, and nitrate) removal test on the bentonite-ZVI mixture with various ZVI content. As the ZVI content increased, contaminants removal efficiencies and swell volume increased, and hydraulic conductivity decreased.

• Geomechanics and Engineering
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• 제29권1호
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• pp.13-23
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• 2022

Peat soil has the characteristics of high moisture content, large void ratio and low shear strength. In this study, unconfined compressive strength and SEM tests are conducted to investigate the effects of ultrahigh moisture content, cement content, organic content and pH value on the strength of solidified peat. As an increase in the cement content and curing period, the failure mode of solidified peat soil changes from ductile failure to brittle failure. The influence of moisture content on the strength of solidified peat is greater than the cement content. As cement content increases from 10% to 30%, strength of solidified peat at a curing age of 28 days increases by 161%~485%. By increasing water content by 100%, decreases of solidified peat at a curing age of 28 days is 42%~79%. Compared with the strength of solidified peat with a pH value of 5.5, the strength of peat with a pH value of 3.5 reduces by 10% ~ 46%, while the strength of peat with a pH value of 7.0 increases by 8% ~ 38%. It is recommended to use filler materials for stabilizing peat soil with moisture content greater than 200%. Because of small size of clay particles, clay added in the cement solidified peat can improve much higher strength that that of sand.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.741-746
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• 2003

The foundation of Noksan area is composed of consolidified sediments including clay mineral, quartz, plagioclase and calcite. The mineral compositions vary dependent on the depth. That is, at the depth of 0-15 meters quartz and plagioclase are more abundant than clay mineral, at the depth of 17-39 meters clay minerals and calcite are more than quartz and plagioclase, at the depth deeper than 40 meters, the amounts of quartz and plagioclase increase slightly and that of clay minerals decrease. Clay minerals of the clayey sediments include illite, smectite, kaolinite and chlorite. At the depth 17-39 meters smectite is abundant and kaolinite is little relatively The pH of suspension is various between 3-9 and decrease to 3-5 at the depth deeper than 40 meters. The result of soil test of clay sediments, water content shows that liquid limit, plastic limit, particle size, unconfined compressive strength varies depending on the depth. The variation of mineralogical, geochemical, engineering properties of soil with the depth are probably due the differing sediments of different sedimentary environment. That is, these variations are considered to be correlated with the sedimentary environment change resulting from the change from continental environment to ocean environment due to the transgression of the interglacial period after the regression the latest glacial period.

• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1230-1236
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• 2016

This study aims to determine the effect of fly ash with a high replacing ratio of clay on the radiation shielding properties of bricks. Some interaction parameters (mass attenuation coefficients, half value layer, effective atomic number, effective electron density, and absorption efficiency) of clay fly ash bricks were measured with a NaI(Tl) detector at 661.6 keV, 1,173.2 keV, and 1,332.5 keV. For the investigation of their shielding behavior, fly ash bricks were molded using an admixture to clay. A narrow beam transmission geometry condition was used for the measurements. The measured values of these parameters were found in good agreement with the theoretical calculations. The elemental compositions of the clay fly ash bricks were analyzed by using an energy dispersive X-ray fluorescence spectrometer. At selected energies the values of the effective atomic numbers and effective electron densities showed a very modest variation with the composition of the fly ash. This seems to be due to the similarity of their elemental compositions. The obtained results were also compared with concrete, in order to study the effect of fly ash content on the radiation shielding properties of clay fly ash bricks. The clay fly ash bricks showed good shielding properties for moderate energy gamma rays. Therefore, these bricks are feasible and eco-friendly compared with traditional clay bricks used for construction.

• 한국조경학회지
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• 제30권5호
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• pp.107-115
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• 2002

This study was carried out to compare artificial soil formulated by blending calcined clay and coconut peat with perlite, then to evaluate this soil as a perlite substitute for use as an artificial planting medium. To achieve this, a determination of the physico-chemical properties and it's effect on plant growth were conducted by comparing those with large perlite grains and small grains. The results are summarized as follows: 1) The bulk density was 0.41g/㎤. This density was lower than that of field soil, but higher than that of large perlite grain(0.23g/㎤) and small grain(0.25g/㎤). The porosity, field capacity, and saturated hydraulic conductivity were 71.3%, 49.2%, and 3.8$\times$10-2cm/s, respectively. The air-permeability, water holding capacity, and drainage were better than or equal to that both large and small perlite grain. 2) It was near-neutral in reaction(pH=6.6). It had a high organic carbon content(65.8g/kg) and a low available phosphoric acid content(84.7mg/kg). It was similar to crop soil in cation exchange capacity(11.4cmol/kg). It had a low exchangeable calcium content(0.71cmol/kg), a low exchangeable magnesium content(0.68cmol/kg), a high exchangeable potassium content(2.54cmol/kg), and a high exchangeable sodium content(1.12cmol/kg). Except for the exchangeable potassium and sodium content, the chemical properties were better than or equal to both large and small grain perlite. The excessive exchangeable potassium or sodium content will inhibit plant growth. 3) In Experiment 1, the plant growth tended to be higher compared to that of large and small perlite gains. But in Experiment 2, it tended to be lower. This might be linked to the excessive exchangeable potassium or sodium content. 4) It could be considered as a renewable perlite substitute for greening of artificial soil. But, it would be necessary to leach the excessive exchangeable potassium or sodium to avoid the risk of inhibiting plant growth.

• Geomechanics and Engineering
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• 제8권1호
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• pp.81-95
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• 2015

The permeability behavior of Ariake clays has been investigated by constant rate of strain (CRS) consolidation tests with vertical or radial drainage. Three types of Ariake clays, namely undisturbed Ariake clay samples from the Saga plain, Japan (aged Ariake clay), clay deposit in shallow seabed of the Ariake Sea (young Ariake clay) and reconstituted Ariake clay samples using the soil sampled from the Saga plain, were tested. The test results indicate that the deduced permeability in the horizontal direction ($k_h$) is generally larger than that in the vertical direction ($k_v$). Under odometer condition, the permeability ratio ($k_h/k_v$) increases with the vertical strain. It is also found that the development of the permeability anisotropy is influenced by the inter-particle bonds and clay content of the sample. The aged Ariake clay has stronger initial inter-particle bonds than the young and reconstituted Ariake clays, resulting in slower increase of $k_h/k_v$ with the vertical strain. The young Ariake clay has higher clay content than the reconstituted Ariake clay, resulting in higher values of $k_h/k_v$. The microstructure of the samples before and after the consolidation test has been examined qualitatively by scanning electron microscopy (SEM) image and semi-quantitatively by mercury intrusion porosimetry (MIP) tests. The SEM images indicate that there are more cut edges of platy clay particles on a vertical plane (with respect to the deposition direction) and there are more faces of platy clay particles on a horizontal plane. This tendency increases with the increase of one-dimensional (1D) deformation. MIP test results show that using a sample with a larger vertical surface area has a larger cumulative intruded pore volume, i.e., mercury can be intruded into the sample more easily from the horizontal direction (vertical plane) under the same pressure. Therefore, the permeability anisotropy of Ariake clays is the result of the anisotropic microstructure of the clay samples.

• 한국의류학회지
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• 제13권3호
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• pp.207-222
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• 1989

New process for the preparation of the artificially soild cloth (ASC) used for detergency evaluation was developed and its detergency was also studied. ASC was prepared by the dipping of cotton cloth in the water in which oily soil, protein (gelatine), carbon black and clay had been dispersed. The clay used for this ASC was red yellowish soil around Mt. Kumjung and was a typical soil in Pusan area. Adhesive status of soil at prepared ASc was examined by an electron microscope, and crystallyzation and color change of used clay were evaluated with the determination of X-ray diffraction and surface reflectance. For the evaluation of detergency by the washing with commercial and model detergents, the behavior of soil removal from this ASC comparing with naturally soiled collar cloth was examined. Those results are summerized as followings; 1) Adhesive ststus of soil at prepared ASc was very similar to that of naturally soiled collar cloth. 2) A crystalline of clay calcined at $800^{\circ}C$ was disappeared in part and color of calcined clay changed into reddish yellow by the decomposition of organic matters. 3) More uniform ASc was prepared with clay calcined at $800^{\circ}C\;that\;200^{\circ}C$ however its detergency prepared from clay calcined at $800^{\circ}C$ was poor 4) A significant relationship between the content of inorganic matter in ASc and K/S value was found, however no significant result between the content of protein contaminated and K/S value was observed. 5) Detergency of prepared ASc had a very similar to that of naturally soiled collar cloh.

• 한국지반공학회논문집
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• 제21권2호
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• pp.67-84
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• 2005

본 연구는 포화된 연약 점성토에 대한 보강효과를 분석하기 위하여 롤러 다짐장비를 사용하여 수행하였다. 시료는 12시간 수침으로 포화 상태를 만들었으며, 철재 롤러로 평면변형을 상태에서 5cm 층 두께로 4층의 다짐을 실시하였다. 보강효과를 분석하기 위하여 무보강 조건 및 부직포와 직포로 구성된 복합보강재를 사용한 보강조건으로 다짐 공시체를 제작하였다. 복합보강재의 배수효과와 인장 보강효과로 고함수비 점성토의 지지력을 증가시켜, 보강토에 대하여 큰 다짐하중을 가할 수 있게 되어 보다 큰 밀도를 효과적으로 얻을 수 있다. 또한 다짐 작업시 보강재에 의해 연직재하 하중에 대한 전단저항 반력의 감소에 의해 다짐효율을 증가시킨다. 공시체 저면에서의 최대 연직응력은 다짐두께가증가 할수록 감소하게 된다. 한편 보강재는 롤러의 연직하부의 지반강성을 증가시켜 응력집중현상이 발생한다. 이로인하여 공시체 저면에서 보다 높은 연직응력 수준을 유지하며 보다 효과적인 다짐 특성을 제공하게 된다. 시험결과로부터 연약점성토의 효과적인 다짐을 위해서는 보강재가 필수적으로 요구된다고 할 수 있다.