• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1693-1706
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• 2008

It is of importance to determine the zero effective stress void ratio($e_{00}$), which is the void ratio at effective stress equal to zero, and the relationships of void ratio-effective stress and of void ratio-hydraulic conductivity for characterizing non-liner finite strain consolidation behavior for ultra-soft dredged materials. The zero effective stress void ratio means a transitional status from sedimentation to self-weight consolidation of very soft soil deposits, and acts as a starting point for self-weight consolidation in the non-linear finite strain numerical analysis such as PSDDF. In this paper, a new method for determining the zero effective stress void ratio has been introduced with the aid of measuring electrical resistivity of the specimen. A correlation between the zero effective stress void ratio and the initial slurry void ratio has been proposed, which can be used in PSDDF analysis as an input parameter. Combining all of the accessible experimental data, the consolidation characteristics of a dredged soil from the Incheon area has been studied in detail.

• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.3
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• pp.59-67
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• 1984

This study was carried out to find physical and mechanical properties of soil in Yongsan project area to support basic data for tidalland reclamation. The main results are as follows. 1. Most of the soils in this area consist of clay and silt, and inorganic materials. 2. Natural moisture contents are ranged from 42.2% to 92.9% initial void ratio, from 1.4 to 2.3 Therefore it takes a longtime in Settlement of considerable depth. 3. Wet unit weights decrease with increasing of the nataral moistare contents as rt=2. 005-0. 0065wn.4. The relationships between compression index. and liquid limit, initial void ratio and natural moisture contents are found as follows respectively. Cc =0. 046+0. O12LL Cc=-0. 068+0.367eo Cc =0. 056+0. OO8Wn 5. Natural moisture content, plastic limit, plastic index, initial void ratio and liquid :limit are directly proportional to clay content ratio. The relationships are found as Wn=26. 083+0. 797Cy PL=14. 223+0. 128Cy P1=0. 457+0. 492Cy eo=0. 757+0. O2Ocy LL=14. 695+0. 620Cy. 6. Initial void ratio and liquid limit are directly proportional to natural moisture con-tent as follows. eo=0. 310+0.022wn LL=6. 275+0.592wn

• Transactions of Materials Processing
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• v.19 no.8
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• pp.480-485
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• 2010

In this work, the closing behavior of cylindrical-shaped voids was experimentally investigated according to various parameters such as reduction ratio in height, initial void size and billet rotation during hot open die forging process. The reduction ratio in height, number of path, and billet rotation were chosen as key process parameters which influence the void closing behavior including the change of void shape and size. On the other hand, values of die overlapping and die width ratio were set to be constant. Void closing behavior was estimated by microscopic observation. Based on the observations, it was confirmed that application of billet rotation is more efficient to eliminate the void with less reduction ratio in height. The experimental results obtained from this study could be helpful to establish the optimum path schedule of open die forging process.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.101-110
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• 2010

This study was performed to evaluate the void ratio and strength of porous polymer concrete used coarse aggregates and unsaturated polyester resin to find optimum mix design of porous polymer concrete for planting block. Also, this study was performed to evaluate the planting properties of herbaceous plant and cool-season grass in porous polymer blocks based on the experimental results of porous polymer concrete to develop environmentally friendly planting blocks. Tests for the void ratio and compressive strength of porous polymer concrete were performed at the curing age 7 days. Also, kinds of plants such as Tall fescue, Perennial ryegrass, Lespedeza and Alfalfa for planting were applied to porous polymer blocks. Within 6 weeks after seed, initial germination ratio, cover view and growth length for planting blocks were estimated by various methods.

• Geomechanics and Engineering
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• v.24 no.3
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• pp.295-305
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• 2021

In this study, design charts for estimating consolidation settlement are proposed according to finite strain consolidation theory using a nonlinear constitutive relationship equation. Results of parametric sensitivity analysis shows that the final settlement, initial height, and initial void ratio exerted the greatest effect, and the coefficients of the void ratio-effective-stress. Proposed design charts were analyzed for three regions using a representative constitutive relationship equation that enables major dredged-reclaimed construction sites in Korea. The regional design charts can be calculated accurately for the final settlement because it is applied directly to the numerical analysis results, except for reading errors. A general design chart applicable to all marine clays is proposed through correlation analysis of the main parameters. A final self-weight consolidation settlement with various initial void ratios and initial height conditions should be estimated easily using the general design chart and constitutive relationship. The estimated final settlement using the general design chart is similar to the results of numerical analysis obtained using finite strain consolidation theory. Under an overburden pressure condition, design charts for estimating consolidation settlement are proposed for three regions in Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1290-1295
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• 2008

The relative density of soil indicate loose and dense state of sand. Because sand is low compressibility, initial relative density of sand is important effect factor of compression and shear behavior. To measure exactly relative density, the exactly maximum and minimum void ratio was determinated by laboratory tests. Generally, vibrating table method is adapted for minimum void ratio(KS F 2345). However KS F 2345 is not consider the particle break during the vibrating table test. In this study, The minimum void ratio is compared with a method of Pluviation and Vibrating table test results using the K-7(crushed sand). It is concluded that the K-7 sand particles were crushed during the vibrating table test and vibrating table test is not a suitable test for a crushed sand $e_{min}$.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.235-244
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• 2001

Liquefaction may be caused by sudden decrease in the soil strength under undrained conditions. This loss of soil strength is related to the development of excess pore pressures. During this study, fines content affects the maximum and minimum void ratios are investigated. The results of static and cyclic triaxial test on silty saturated sands are presented. These tests are performed to evaluate liquefaction strength and static and cyclic behavior characteristics. The samples are obtained from Saemangeum and drying on air. The main results are summarized as follows : 1) The maximum and minimum void ratio lines follow similar trends. 2) Maximum and minimum void ratios are established at 20~30% fines content. 3) As confining pressures and overconsolidation ratio are increased, the resistance to liquefaction are increased. 4) Instability friction angles are increased with increasing initial relative density. 5) The resistance to liquefaction are decreased with increasing effective stress ratio.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.4
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• pp.4242-4250
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• 1976

The determination of the pre-consolidation load known to have a great effect on the consolidation characteristics of the soil have been researched and discussed in detail by many other researchers. A study was undertaken to investigate and compare the effect of pre-consolidation loads on the coefficient of permeability and the consolidation characterisics of soil through the consolidation test on the three types of soil samples. The results of this study are follows; 1. Large compression index is dependent on initial void ratio of the sample being used and the pressure-void ratio curve shows a curved linear relationship in over-consolidated area but a linear relationship in normally consolidated area.2. Settlement-time curve is S-shaped where the pressure is larger than pre-consolidation load and regardless of over-burden pressure, it is a similar straight line respectively in the secondary consolidation area. 3. Primary consolidation ratio of the sample increases almost linearly with the increase of over-burden pressure but the coefficient of volume compressibility decreases linearly with the increase of it. 4. Time factor of a certain degree of consolidation increases with over-burden pressure but the coefficient of consolidation decreases with it in over-consolidated area. There is a linear relationship between them in normally consolidated area. 5. The void ratio of completion point of primary consolidation decreases linearly with over-burden pressure. 6. The coefficient of permeability of sample decreases linearly with over-burden pressure in normally consolidated area, also it increases linearly with increment of the void ratio of the sample.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.489-494
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• 2010

A geo-composite soil (GCS) is a stabilized mixture of bottom ash, cement and dredged soil. Various samples with different mass ratios of mixtures were tested under curing time of 7 and 28 days to investigate physical properties and compressive strength. This paper focused on the effect of bottom ash on the strength characteristics of Busan marine dredged soil. Cement has been added as an additive constituent to enhance self-hardening of the blended mixture. The unconfined compressive strength of GCS increases with an increase in curing time due to pozzolanic reaction of the bottom ash. The strength after 28 days of curing is found to be approximately 1.3 to 2.0 times the strength after 7 days of curing, regardless of mixture conditions. The secant modulus of GCS is in the range of 55 to 134 times the unconfined compressive strength. The correlation of unconfined compressive strength with bottom ash content and initial void ratio are suggested.

• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.79-89
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• 2008

In this study, a series of undrained cyclic triaxial tests were performed with three different consolidation stress ratios ($K_c$=1.0, 1.5, 2.0) to investigate the undrained shear strength characteristics of sands with respect to the amount of contained silt located around the basin of Nak-dong River. The test results show that the more the sand has silt, the lower is cyclic shear stress ratio (CSR) in all $K_c$ and that the higher $K_c$ goes, the larger CSR decreases due to the increase of contained silt. The excessive pore pressure caused during shearing has an influence on the decrease of CSR by the high initial pore pressure in proportion to the amount of contained silt regardless of the $K_c$ value. After consolidation, the analysis of the skeleton void ratio of the sample reveals that the main cause of the decrease of CSR as well as the increase of the initial excessive pore pressure is the increase of the skeleton void ratio in proportion to the amount of contained silt.