• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.183-194
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• 2004

It's essential process to study non-linear material function related to characteristics of compressibility and permeability when we predict the consolidation behavior of soft clay ground. In this study, laboratory tests were conducted to find out the material function using marine clay. Standard oedometer test and Rowe cell test were performed with conditions, which were classified into vertical drainage only, radial drainage only and vertical-radial drainage case. Modified oedometer test equipment was developed to find out the material function and special extrusion device was originated to minimize the sample disturbance effect. Reliability of the results in modified oedometer test could be confirmed by comparing with the Rowe cell's one. Effective stress - void ratio - permeability relations were analyzed using all testing results. As a result, void ratio with effective stress level could be expressed by the power function and permeability with void ratio could be expressed by exponential function. In soft clay with high initial water content and low shear strength, non-linear characteristics related to compressibility and permeability varied with wide range by the effective stress levels. It's important to note that non-linearity of the material function should be considered at prediction of the consolidation behavior.

• 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 Geosynthetics Society
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• v.9 no.3
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• pp.29-37
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• 2010

This study aims at evaluating the engineering properties of very poor graded fine sands deposited on the sea. Using materials sampled at SAEMANKEUM area, a series of rowe cell consolidation tests and triaxial compression tests are conducted in order to evaluate the characteristics of deformation and shear strength by the relative density. Prior to those tests, a maximum and a minimum relative densities are obtained. As a result, it appears that the minimum void ratio is 0.88, and the maximum compactible relative density is about 71%. In addition, internal frictional angle appears to increase linearly with an increase of the relative density which is similar to that of the port KUNJANG.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.29-34
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• 2008

A large diameter sampler was developed to take undisturbed samples from not only soft ground but also sandy and weathered ground. The large diameter sampler which was developed in Korea Institute of Construction Technology(KICT-type large diameter sampler) was manufactured based on the principle of triple core barrel sampling. A specially designed cutting device was used to cut and contain various kinds of samples in the sampler during a sampling and retrieval procedure. By adjusting the stiffness of the spring located at the top of the sampler, the distance between the cutting shoe and auger can be controlled in accordance with the ground condition. In order to investigate the applicability of the developed sampler and compare the quality of the samples taken by the sampler with that by the traditional thin-walled tube sampler, samples were taken at various sites according to the ground condition. And a series of laboratory tests such as the unconfined compress ion test, triaxial compression test, oedometer test, large diameter Rowe cell consolidation test (D: 150 mm) were performed. The test results showed that the samples by the KICT-type large diameter sampler show higher quality than the samples by the thin-walled tube sampler. And the validity and applicability of the developed KICT-type large diameter sampler was confirmed accordingly.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.125-132
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• 2007

The oedometer, radial CRS and Rowe cell tests, composite discharge capacity tests and smear effect tests are carried out to estimate the parameters for the reliability-based design of vertical drain method. Also the sensitivity analysis, the probabilistic and deterministic solutions of radial consolidation theory are presented. The result of probabilistic analysis was compared to that of deterministic analysis using the tested and estimated parameters. The results indicated that the drain spacing in the deterministic method is larger than that in the probabilistic method because the former does not consider the uncertainties in the geotechnical property. The divergence of two methods is dependent on the probability of achieving target degree of consolidation by a given time and the coefficient of variation (COV) of the coefficient of horizontal consolidation ($c_h$).

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.349-359
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• 2011

The consolidation behavior of soft clay is controlled mainly by its compressibility and deformation characteristics. Soil permeability depends on various soil characteristics, including the soil type and anisotropy. The coefficient of permeability of soft clay is determined by using a laboratory test (the Oedometer test) or a piezocone test. The latter test is useful for estimating the permeability characteristics from $c_h$ and $k_h$ by performing an excess pore-pressure dissipation test. This study seeks to validate an existing theoretical formula in applying it to marine clay, and to assess the relation between $k_h/k_c$ and the mechanical properties of soft clay. Piezocone tests and laboratory tests were performed using sediment from the Yellow Sea and from the South Sea near Korea. We compared $k_h/k_v$ values obtained using the piezocone test and using laboratory consolidation tests. The obtained values are similar to the values obtained by Jamiolkowski et al. (M application); therefore, the latter values are recommended to be used as $k_h/k_v$.

• Journal of the Korean GEO-environmental Society
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• v.12 no.12
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• pp.47-54
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• 2011

Consolidation behavior of soft clay is generally to be affected by its compressibility and deformation characteristics. Especially, soil permeability depends on soil characteristics including its type of anisotropy. Coefficient of permeability of soft clay is mostly estimated by using laboratory(Oedometer test) and in-stiu piezocone test. The permeability characteristics of soft clay is estimated by excess pore pressure dissipation test results. In this study, the tests were performed to find out the validity of the existing theoretical formula in clay by pore pressure dissipation test and laboratory test results. After grasping of variation the coefficient of permeability ratio(${k_{h}/k_{v}}$) in different clay soils, it was found out adequate solution of in-stiu permeability ratio(${k_{h}/k_{v}}$). Piezocone tests and laboratory tests were performed at the site of pilot project of ground improvement at Yangsan-Mulgeum, Gyeongsangnam-do. Comparisons of the estimated values of ${k_{h}/k_{v}}$ using piezocone tests results and those from laboratory consolidation tests were carried out. Test results show that values of ${k_{h}/k_{v}}$ by piezocone test result(5.85) is similar of it's laboratory test(5.28).

• Journal of Ginseng Research
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• v.45 no.1
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• pp.66-74
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• 2021

Background: Abnormal chloride (Cl-) transport has a detrimental impact on mucociliary clearance in both cystic fibrosis (CF) and non-CF chronic rhinosinusitis. Ginseng is a medicinal plant noted to have anti-inflammatory and antimicrobial properties. The present study aims to assess the capability of red ginseng aqueous extract (RGAE) to promote transepithelial Cl- secretion in nasal epithelium. Methods: Primary murine nasal septal epithelial (MNSE) [wild-type (WT) and transgenic CFTR-/-], fisher-rat-thyroid (FRT) cells expressing human WT CFTR, and TMEM16A-expressing human embryonic kidney cultures were utilized for the present experiments. Ciliary beat frequency (CBF) and airway surface liquid (ASL) depth measurements were performed using micro-optical coherence tomography (μOCT). Mechanisms underlying transepithelial Cl- transport were determined using pharmacologic manipulation in Ussing chambers and whole-cell patch clamp analysis. Results: RGAE (at 30㎍/mL of ginsenosides) significantly increased Cl- transport [measured as change in short-circuit current (ΔISC = ㎂/㎠)] when compared with control in WT and CFTR-/- MNSE (WT vs control = 49.8±2.6 vs 0.1+/-0.2, CFTR-/- = 33.5±1.5 vs 0.2±0.3, p < 0.0001). In FRT cells, the CFTR-mediated ΔISC attributed to RGAE was small (6.8 ± 2.5 vs control, 0.03 ± 0.01, p < 0.05). In patch clamp, TMEM16A-mediated currents were markedly improved with co-administration of RGAE and uridine 5-triphosphate (8406.3 +/- 807.7 pA) over uridine 5-triphosphate (3524.1 +/- 292.4 pA) or RGAE alone (465.2 +/- 90.7 pA) (p < 0.0001). ASL and CBF were significantly greater with RGAE (6.2+/-0.3 ㎛ vs control, 3.9+/-0.09 ㎛; 10.4+/-0.3 Hz vs control, 7.3 ± 0.2 Hz; p < 0.0001) in MNSE. Conclusion: RGAE augments ASL depth and CBF by stimulating Cl- secretion through CaCC, which suggests therapeutic potential in both CF and non-CF chronic rhinosinusitis.