• Journal of Industrial Technology
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• v.26 no.B
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• pp.83-92
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• 2006

A probabilistic analysis model. one of reliability analysis methods introducing the concept of variables, was developed to investigate the uncertainty of dominant factors influencing the degree of consolidation in the radial consolidation theories. Based on the developed probabilistic analysis model, sensitivity study of those factors was performed to find their trends of affecting the degree of consolidation in the vertical drain method. Various radial consolidation theories, proposed by Barron(1948), Hansbo(1979), Yoshikuni(1979) and Onoue(1988), were used for this parametric study with the influencing factors such as size of smear zone, reduction ratio of permeability in the smear zone, discharge capacity, permeability for horizontal flow and coefficient of consolidation for horizontal flow. As results of this sensitivity study, for the given consolidation theory, contribution of each factor to the degree of consolidation was figure out and compared to each other. For the given value of each factor, the sensitivity to the degree of consolidation in the various theories was evaluated and their applicability and limitations were assessed.

• 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 Furniture Society
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• v.18 no.4
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• pp.261-267
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• 2007

This report describes the wood anatomy and 1% safranine solution penetration depth in radial and longitudinal directions of Anthocephalus chinensis belonging to the family Rubiaceae native to Bangladesh. The wood of this species was mostly characterized by diffuse porous, vessel with simple perforation plate, vestured alternate intervessel pittings, relatively medium vessel elements and fiber, and nonseptate fiber with distinctly bordered pits at radial wall. The body ray cell was procumbent with 2 to over 4 rows of upright and square marginal cells. Sometimes, the rays with procumbent, square and upright cells were mixed. Latewood fiber was thin to thick walled while it was very thin walled in earlywood. Axial parenchyma was diffuse, vasicentric, 5-8 cells per parenchyma strand dominantly present. Liquid penetration depth was observed in radial and longitudinal directions at moisture level of 7.42%. Longitudinal penetration was found 6.3 times higher than radial penetration. The initial penetration rate of safranine solution was high, but gradually decreased during the course of time. Different anatomical features were found to be responsible for the variation of safranine solution penetration depth compared to Gmelina arborea.

• Journal of the Korean Geotechnical Society
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• v.28 no.1
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• pp.41-53
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• 2012

As the permeability of soil adjacent to the vertical drain has a decisive effect on the rate of consolidation, the permeability of smear zone governs the rate of radial consolidation of PVD installed soft ground. In this study, a method was suggested to analyze the radial consolidation, based on consolidation characteristics of remolded clay, and was used to evaluate the consolidation of soft clay layer in Busan Newport. The suggested method provides more reliable consolidation behaviors than the conventional approach, which is based on the consolidation characteristics of undisturbed clay. The suggested method is also observed to be relatively insensitive to the uncertainty of $k_h/k_s$. The comparison between the analysis and field measurement revealed that the suggested method provided a reliable prediction on the rate of consolidation of PVD installed Busan new port clay and that an appropriate extent of smear zone was evaluated as about $3d_w$ by back analysis.

• Journal of the Korea Furniture Society
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• v.28 no.3
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• pp.248-258
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• 2017

A study was carried out to observe the 1% aqueous safranine solution flow speed in longitudinal and radial directions of softwood Thuja orientalis L., diffuse-porous wood Gmelina arborea Roxb., and ring-porous wood Phellodendron amurense Rupr., Longitudinal flow was considered from bottom to top while the radial flow was considered from bark to pith directions. In radial direction, ray cells and in longitudinal direction tracheids, vessel and wood fiber were considered for the measurement of liquid penetration speed at less than 12% moisture contents(MC). The variation of penetration speed for different species was observed and the reasons behind for this variation were explored. The highest radial penetration depth was found in ray parenchyma of T. orientalis but the lowest one was found in ray parenchyma of P. amurense. The average liquid penetration depth in longitudinal trachied of T. orientalis was found the highest among all the other cells. The penetration depth in fiber of G. arborea was found the lowest among the other longitudinal cells. It was found that cell dimension and also meniscus angle of safranine solution with cell walls were the prime factors for the variation of liquid flow speed in wood. Vessel was found to facilitate prime role in longitudinal penetration for hardwood species. The penetration depth in vessel of G. arborea was found highest among all vessels. Anatomical features like ray parenchyma cell length and diameter, end-wall pits number were found also responsible fluid flow differences. Initially liquid penetration speed was high and the nit gradually decreased in an uneven rate. Liquid flow was captured via video and the penetration depths in those cells were measured. It was found that even in presence of abundant rays in hardwood species, penetration depth of liquid in radial direction of softwood species was found high. Herein the ray length, lumen area, end wall pit diameter determined the radial permeability. On the other hand, vessel and fiber structure affected the longitudinal flow of liquids. Following a go-stop-go cycle, the penetration speed of a liquid decreased over time.

• Journal of the Korea Furniture Society
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• v.18 no.4
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• pp.312-316
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• 2007

A study was conducted to know 99.5% ethyl alcohol penetration depth in radial and longitudinal direction of Castanea crenata. Alcohol penetration depth was found higher in longitudinal direction by about 12.47 times. In both earlywood and latewood, fiber conducted alcohol in higher depth than that of large and small vessel. Penetration depth of alcohol after 15.0 second of penetration in longitudinal direction, there was no significant difference among fiber in sapwood and heartwood, and vessel in sapwood. At the beginning of penetration the speed was high and then gradually decreased.

• Geomechanics and Engineering
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• v.7 no.1
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• pp.105-131
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• 2014

In this paper, the effects of variability of smear zone characteristics induced by installation of prefabricated vertical drains on the preloading design are investigated employing analytical and numerical approaches. Conventional radial consolidation theory has been adopted to conduct analytical parametric studies considering variations of smear zone permeability and extent. FLAC 2D finite difference software has been employed to conduct the numerical simulations. The finite difference analyses have been verified using three case studies including two embankments and a large-scale laboratory consolidometer with a central geosynthetic vertical drain. A comprehensive numerical parametric study is conducted to investigate the influence of smear zone permeability and extent on the model predictions. Furthermore, the construction of the trial embankment is recommended as a reliable solution to estimate accurate smear zone properties and minimise the post construction settlement. A back-calculation procedure is employed to determine the minimum required waiting time after construction of the trial embankment to predict the smear zone characteristics precisely. Results of this study indicate that the accurate smear zone permeability and extent can be back-calculated when 30% degree of consolidation is obtained after construction of the trial embankment.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.832-846
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• 2020

The purpose of this research was to evaluate the vapor permeability of nine different species of domestic softwood and the vapor permeability evaluation through the production of small wall structures for the developing applications, utilizing the vapor permeability of wood. In addition, the permeability evaluation was attempted by means of the production of a small wall structure injected with a waste material, bottom ash, as a moisture absorbent for improving the permeability. Consequently, the results of the vapor permeability evaluation by means of S_d value are as follows: (1) It was observed that Abies holiphylla, Picea jezoensis, Ginkgo biloba, Pinus koraiensis and Pinus rigida are permeable to moisture among 9 species of domestic softwood in Korea. (2) By means of this, semi-permeability efficiency was evaluated when producing a small wall structure. (3) Besides, improved effects of permeability were evaluated when producing a small wall structure inserted with bottom ash. As a result, it was confirmed that the S_d value of Pinus koraiensis turned out to be 1.63, which is superior to other 8 tree species.

• The Journal of Engineering Geology
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• v.24 no.2
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• pp.201-215
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• 2014

This study was performed to investigate the correlation between hydraulic conductivity and the flow rate of an aquifer, with the flow rate calculated from the laterals of the radial collector well using data obtained by the development project of riverbank filtration (Second Phase) in Changwon City. The hydraulic conductivity was empirically calculated from unconsolidated sediments collected from a sandy gravel layer along the middle-to-downstream sections of the Nakdong River. The Beyer equation produced the most suitable hydraulic conductivity from the various empirical formulas employed. The calculated hydraulic conductivity ranged from 0.083 to 0.264 cm/s, with an average value of 0.159 cm/s, suggesting that the aquifer in the study area possesses a high permeability with a good distribution of sandy gravel. The relationship between the calculated hydraulic conductivity in the aquifer and the entrance velocity into the screen, the flow rate was analyzed through the linear regression analysis. From the result of regression analysis, it showed that the hydraulic conductivity and the entrance velocity into the screen and the flow rate have a linear regression equation having about 72% of the high correlation. The result of verification in the measured data between each variable showed a high suitability from being consistent with the approximately 72% in the linear regression analysis. This study demonstrates that the groundwater flow rate can be estimated within the laterals of the radial collector well using a linear regression equation, if the hydraulic conductivity of the aquifer is known. This methodology could thus be applicable to other aquifers with hydraulic conductivity and permeability parameters similar to those in the present study area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2C
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• pp.75-81
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• 2008

In this study, a series of laboratory column test on Suction Drain Method which is one of the way to make an soft ground improvement were conducted in order to investigate the effect of the Hardening Zones and the ratio of improvements depending on periods of the improvements and various applied suction pressures. On this occasion, the experimental conditions are followings; in the case of the periods of effectiveness, 4 days, 8 days, 12 days, 16 days, 20 days and in the case of the applied pressures of the Suction are -20 kPa, -40 kPa, -60 kPa and -80 kPa were carried out. As a result of test, settlement increased with suction pressure and duration increase, and gradually converged. Also, as comparing permeability decrease ratio with which calculated back from water content and numerically predicted using Hansbo's radial consolidation theory, measured value was almost coincide with predicted value when permeability decrease ratio was assumed as 2~3. Furthermore, the hardening zone was appeared within 7~8 cm of whole radial (25 cm).