• 한국환경복원기술학회지
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• 제3권1호
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• pp.52-61
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• 2000

Permeability is important factor in the geotechnical problems, such as seepage discharge and dissipation of excess pore water pressure. The Kozeny-Carman equation works well for graded soils but serious discrepancies are found in clays. Major factor for these discrepancies is the tortuous flow path and unequal pore size. To estimate the permeability of fine grained soils, a permeability equation in which swelling potential is coupled with Kozeny-Carman equation is proposed in this study. To verify proposed equation, a series of variable head permeability test was carried out for steel making slag and sludge mixed with bentonite. The coefficients of permeability which is measured in the laboratory is compared with the values by the proposed equation. From the comparison, it is shown that the proposed equation can predict the coefficient of permeability of clays with satisfaction. As steel making slag and sludge is industry waste, it is reused as material of road foundation and cement but the rate of use is low. It mixed sodium-bentonite with high swelling property and permeability decrease effect. Then, Admixture investigates reuse possibility as liner of waste fill.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.362-369
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• 2005

Studying unsaturated soil mechanics, determination of soil water characteristic curve and permeability equation is an essential factor but it is not easy. In this research a new testing apparatus was developed to determine soil water characteristic curve and permeability equation. The testing to get saturated permeability coefficients and soil water characteristic curves for two soils was performed by using the developed testing apparatus. First, a saturated permeability testing was performed and then the testing to get soil water characteristic curve of a drying process was performed. Next, the testing to get soil water characteristic curve of a wetting process was performed. Testing results showed hysteresis phenomena between soil water characteristic curve of a drying process and soil water characteristic curve of a wetting process. The permeability equations were determined by a theoretical method where a saturated permeability coefficient and a soil water characteristic curve were used.

• 지질공학
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• 제19권3호
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• pp.409-415
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• 2009

일반적으로 흙의 투수계수를 예측하기 위하여 Kozeny-Carman 공식이 널리 적용되어왔다. 그러나 Kozeny-Carman 공식은 모래질 흙의 투수계수 예측에는 좋은 결과를 나타내나 점성토와 같은 세립토에는 적합하지 않다. 따라서 본 논문에서는 Kozeny-Carman 공식을 고려하여 점성토의 투수계수를 예측할 수 있는 이론식을 제시하였다. 이론식을 위해 해안가의 점성토와 댐의 심벽재로 사용하는 다짐 점성토의 토질특성에 대해 조사 분석하였다. 연구 결과, 토질특성과 투수계수 사이의 주요 관계 요소로, 해안가 점성토는 점토함유율, 다짐 점성토는 #200통과율과 관계가 있는 것으로 나타났다.

• 지질공학
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• 제28권1호
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• pp.1-9
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• 2018

We propose a borehole test technique to estimate permeability of rocks in borehole. The borehole tests are hydraulic injection tests such as leak-off test and hydraulic fracturing tests, which are originally conducted for stress or casing integrity assessment and not for permeability measurement. We use one-dimensional radial diffusion equation to interpret fluid injection test results in terms of permeability. We apply this technique to a leak-off test conducted at a depth of 700 m in a wellbore, where rock formation is mudstone. The estimated permeability is at an order of $10^{-16}m^2$, which is somewhat high but within the range reported for mudstones previously. Quantitative rick assessment suggests that an accurate measurement of open hole section length is important to improve reliability of results. More data may be needed to ensure the reliability of this technique. If validated, however, this technique can provide cost-effective estimation of in situ permeability without conducting independent permeability tests in borehole.

• 한국지반공학회논문집
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• 제21권5호
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• pp.59-64
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• 2005

불포화토를 연구하는데 있어 함수특성곡선과 투수계수방정식을 결정하는 것은 필수요소이나 이는 쉬운 일이 아니다. 본 연구에서는 함수특성곡선과 투수계수방정식을 얻기 위한 새로운 시험장치가 개발되었다. 개발된 시험장치를 사용하여 두 종류의 토사에 대해 포화투수계수시험과 함수특성곡선을 결정하기 위한 시험을 실시하였다. 시험진행순서는 먼저 포화투수계수시험을 실시한 후, 함수특성곡선의 건조과정에 대한 시험을 실시하고 다음으로 함수특성곡선의 습윤과정에 대한 시험순으로 진행하였다. 시험결과에 의하면 건조과정의 함수특성곡선과 습윤과정의 함수특성곡선 간에는 이력현상이 존재함을 알 수 있었다. 투수계수방정식의 결정은 시험으로부터 얻어진 포화투수계수와 함수특성곡선 이용하여 구하는 이론적인 방법을 사용하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.334-341
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• 2004

The coefficient of permeability is one of the most important properties in unsaturated soils. The permeability varies with change in the water content as the soil water characteristic curve(SWCC) does. Thus the permeability curve of unsaturated soils has the similar shape with the soil-water characteristic curve(SWCC). Therefore, the methodologies have been studied to simply predict the unsaturated permeability from the SWCC. In this study, the experimental tests of SWCC and permeability were carried out for domestic weathered granite soils. The SWCC test results were fitted to Fredlund and Xing's SWCC equation and then it was found that there are some relationships between the parameters of SWCC equation and the basic soil properties. Accordingly we used an ANN(artificial neural network) model to obtain the SWCC parameters from the basic soil properties. Finally, the coefficients of permeability were predicted from these results by a prediction model.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.160-165
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• 1999

Osmotic pressure induced by semi-permeability of hardened cement pasts and cement mortar was studied, which was considered to be a cause of failure such as separation and blistering of floor coatings or wall coatings from the concrete substrate. The specimens with a water cement ratio of 45, 60 and 75% were installed between the solution of sodium chloride and distilled water. First, we measured water flux from distilled water to sodium chloride and the ion flux of Na+ and Cl- through the specimens. Then, we measured osmotic pressure induced by semi-permeability of the specimens using an apparatus which was specially developed for this study. It was made clear that hardened cement paste and cement mortar have properties of semipermeability, and the osmotic pressure is closely related to their water cement ratio. Finally, we calculated the osmotic pressure according to Staverman's equation, which was obtained for organic membranes, and tried to explain quantitatively the observed pressure.

• Geomechanics and Engineering
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• 제22권5호
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• pp.375-384
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• 2020

In this study, the application of conventional cubic law to a deep depth condition was experimentally evaluated. Moreover, a modified equation for estimating the rock permeability at a deep depth was suggested using precise hydraulic tests and an effect analysis according to the vertical stress, pore water pressure and fracture roughness. The experimental apparatus which enabled the generation of high pore water pressure (< 10 MPa) and vertical stress (< 20 MPa) was manufactured, and the surface roughness of a cylindrical rock sample was quantitatively analyzed by means of 3D (three-dimensional) laser scanning. Experimental data of the injected pore water pressure and outflow rate obtained through the hydraulic test were applied to the cubic law equation, which was used to estimate the permeability of rock fracture. The rock permeability was estimated under various pressure (vertical stress and pore water pressure) and geometry (roughness) conditions. Finally, an empirical formula was proposed by considering nonlinear flow behavior; the formula can be applied to evaluations of changes of rock permeability levels in deep underground facility such as nuclear waste disposal repository with high vertical stress and pore water pressure levels.

• 한국지반공학회논문집
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• 제22권1호
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• pp.45-52
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• 2006

흙차수층을 설계할 때 혼합되는 벤토나이트의 적정량을 구하는 식을 유도하였다. 벤토나이트는 포화될 경우 팽창성이 큰 흙이며 또한 최대로 팽창한 경우에도 투수계수는 $1\times10^{-7}cm/sec$ 이하를 유지한다. 이러한 벤토나이트의 성질을 이용하여 벤토나이트를 일반 흙과 혼합할 때 불투수층의 조건을 만족시키는 혼합율을 구하는 이론식을 구하였다. 그 개념은 포화된 벤토나이트가 흙 속의 간극을 채우면, 물은 벤토나이트로만 흐르게 되고, 벤토나이트는 불투수층으로서의 조건을 만족시키므로 그 결과 벤토나이트 혼합토 역시 차수층으로서의 조건을 만족시킨다는 것이다. 본 이론을 입증하기 위한 실험을 실시하였으며, 실험결과로부터 차수층을 얻기 위한 적정 혼합율을 구하는 방법을 제안하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1043-1052
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• 2009

To derive easily the coefficient of permeability from several other soil properties, the estimation model of coefficient of permeability was proposed using linear regression analysis. The coefficient of permeability is one of the major factors to evaluate the soil characteristics. The study area is located in Kangwon-do Pyeongchang-gun Jinbu-Myeon. Soil samples of 45 spots were taken from the study area and various soil tests were carried out in laboratory. After selecting the soil factor influenced by the coefficient of permeability through the correlation analysis, the estimation model of coefficient of permeability was developed using the linear regression analysis between the selected soil factor and the coefficient of permeability from permeability test. Also, the estimation model of coefficient of permeability was compared with the results from permeability test and empirical equation, and the suitability of proposed model was proved. As the result of correlation analysis between various soil factors and the coefficient of permeability using SPSS(statistical package for the social sciences), the largest influence factor of coefficient of permeability were the effective grain size, porosity and dry unit weight. The coefficient of permeability calculated from the proposed model was similar to that resulted from permeability test. Therefore, the proposed model can be used in case of estimating the coefficient of permeability at the same soil condition like study area.