• Geotechnical Engineering
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• v.10 no.1
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• pp.63-70
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• 1994

In-situ soil is anisotropically consolidated at rest, and the coefficient of earth pressure at rest $K_0$ is dependent on the properties of soil and stress history. In order to estimate roughly the in-situ undrained shear strength of a $K_0$-anisotropically normally consolidated clay from isotropic consolidated undrained test, consolidated undrained shear testy with four different consolidation pressure ratios ($K={\sigma}'_{3c}/{\sigma}'_{1c}$) were performed and test results showed K-$\alpha$ relationship, representing the strength ratio $\alpha$ as ($S_u/{\sigma}'_{1c})_{CKU}=\alpha(S_u/{\sigma}'_{1c})_{CIU}$. Strength ratio u increases with increasing consolidation pressure ratio. And the angle of internal friction $\Phi'$and angle ratio $\Phi'_{CKU}/\Phi'_{CIU}/$ are increased with the increament of K-value.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.69-75
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• 2013

Suction stress is evaluated from soil water retention curves in order to deduce effective stress in unsaturated soils. $K_0$ consolidated triaxial tests were performed for silty sand to interpret effective stress in consolidation and shearing of unsaturated soils. Suction stresses from both consolidation stress and shear strength in triaxial tests were compared with those from soil water retention curves. The effective stresses on consolidation and shear strength are on each unique line, which are the same as that of the saturated case. It was found that the effective stress from soil water retention curves agrees with those from consolidation and shear strength in triaxial tests.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.09a
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• pp.73-78
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• 2000

The reinforced soil has been widely used for constructing retaining walls and embankment with steep slope. However, the benefits of soil reinforcing are often-restricted by a lack of good quality backfill material. In this study, plane strain compression tests were carried out to study the effects of preloading on the behavior of geosynthetic-reinforced saturated clay. For the unreinforced and reinforced soil, drained and undrained shearing tests were peformed after anisotropic consolidation in a constant strain rate. A preoading test was carried out by preloading, creep, unloading, aging and undrained shearing after anisotropic consolidation(K=0.3, σ'₃=50 kPa). It was observed that a reinforced clay, Kanto loam, can have a great initial secant modulus in undraind condition by well compaction and over consolidation. The results shown that the increasing of drained strength should be used to apply a large preloading in the case of reinforced clay.

• Journal of Magnetics
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• v.11 no.3
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• pp.126-129
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• 2006

The phosphate coating on the $(Fe_{0.97}Cr_{0.03})_{76}(Si_{0.5}B_{0.5})_{22}C_2$ amorphous powders with an average size of 10 ${\mu}m$ in diameter has been carried out in aqueous 1.0-2.0 wt% $H_3PO_4$ solutions, and the consolidation behavior and magnetic properties of their compressed powder cores has been investigated. The phosphate coating could provide efficient electrical insulation between amorphous powders and improved consolidation ability at room temperature. Especially when the powders were treated in more concentrated phosphoric acid solution, enhanced phosphate covering and higher frequency/dc-bias stability were achieved. The powder cores phosphate-coated in 2.0 wt% $H_3PO_4$ solution exhibited constant permeability of 21 up to 10 MHz, 110 of the quality factor at 0.9 MHz, 610 mW/cm3 core loss at 100 kHz/0.1 T and 89 of percent permeability at 100 kHz.

• Tuberculosis and Respiratory Diseases
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• v.62 no.6
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• pp.479-485
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• 2007

Background: The purpose of this study was to evaluate the differences in CT findings according to sputum smear-positive or -negative results in patients with active pulmonary tuberculosis having a single cavity. Methods: A total of 32 patients with active pulmonary tuberculosis having a single cavity on CT were classified into two groups: smear-positive (n=19) and smear-negative (n=13). The CT findings were reviewed retrospectively. The presence of consolidation, the number of lobes showing consolidation, ground-glass opacity, micronodules and nodule, the maximum diameter of the cavity, and the shape and maximum thickness of the cavity wall were assessed. Result: The maximum diameter of the cavity was $33.84{\pm}13.65mm$ and $27.08{\pm}9.04mm $ in the smear-positive and -negative groups, respectively (p>0.05). The amount of consolidation and the number of lobes with consolidation were found to be 89.5% and 30.8% (p=0.01) and $1.37{\pm}0.90$ and $0.31{\pm}0.48$ (p=0.0002) in the smear-positive and -negative groups, respectively. Consolidations in two or more lobes were only noted in 31.6% of in the sputum smear- positive group (p< 0.05). There were no other significant differences between the two groups. The sensitivity, specificity, positive and negative predictive values for the presence of consolidation were 89.5%, 69.2%, 73.9%, and 81.8%, respectively. Conclusion: While the absence of consolidation on CT may be associated with sputum smear-negative results in patients with active pulmonary tuberculosis having a single cavity, the presence of consolidation in two or more lobes on CT may be associated with spear-positive results in these patients.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1039-1046
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• 2005

After clay particles have been sediment isotropically, the clay deposits have been consolidated under $K_0$-stress system. Therefore, in order to predict the behavior in-situ of normally consolidated clays, the laboratory test should be enforced under $K_0$-stress system and should obtain the characteristics of normally consolidated clays. And relationship of stress-strain on clay is effected on not only method of consolidation but also characteristic of visco-plastic behavior. Saturated clay is effected more this trend. So, rate of strain is considered to understand exact stress-strain relationship. In this study, the series of undrained triaxial compression tests were preformed on remolded specimens which was made by slurry of clay, consolidated under $K_0$-stress systems. And the undrained triaxial compression test were preformed to examine behavior of stress-strain relationship due to rate of shear strain relationship due to rate of shear strain.

• 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.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.300-306
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• 2014

To recycle coal bottom ash(denoted here as CBA) generated from thermal power plants as a functional construction material, artificial soil(denoted as AS) containing CBA with dredged soil(denoted as DS) at a ratio(wt%) of 70 : 30 was manufactured by means of material engineering with sintering in a rotary kiln at $1125^{\circ}C$ using a green body formed via extrusion processing. The properties of the soil mechanics of the AS and the as-received CBA were analyzed and compared. Compaction testing results determined an optimum moisture content of the AS and CBA at 18%. During these tests, the maximum dry unit weights of the materials were similar, at 1.57 and 1.58 $t/m^3$, respectively. The compressive strength levels of the AS and CBA concrete specimens were 5.1 and 5.4 $t/m^3$, respectively, both of which increased after materials engineering processing. In a consolidation test, the compression index of the AS and CBA was found to be $0.114{\pm}0.001$ in both cases. The values were similar regardless of the materials engineering processes, but during the consolidation of AS, its coefficient was higher than that of the CBA materials.

• Korean Journal of Agricultural Science
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• v.25 no.2
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• pp.225-234
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• 1998

This study was compared the degree of consolidation by Hyperbolic, Curve fitting, Asaoka's, Monden's methods using measured value with theoretical curve in consideration of smear effect and well resistance. The results of the study were summarized as follows ; 1. The degree of consolidation by Hyperbolic method was underestimated than the degree of consolidation by Curve fitting, Asaoka's, and Monden's methods. 2. Typical range of horizontal coefficient of consolidation was $C_h=(2{\sim}3)C_v$ in the case considering smear effect and well resistance, and $C_h=(0.5{\sim}2.5)C_v$ in the case disregarding smear effect and well resistance. 3. The degree of consolidation obtained by ground settlement monitoring was nearly same value when the coefficient of permeability of smear zone by back analysis was shown the half that of in-situ and the diameter of smear zone was shown double that of mendrel. 4. Increasing of diameter reduction ratio of drain, the time of consoildation was delayed. The affection of well resistance the case of small coefficient of permeability was much more than that in the case of large coefficient of permeability. It was recommended that design of diameter reduction of drain consider smear effect and well resistance.

• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.92-100
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• 2001

It is very important to determine the coefficient of earth pressure at rest accurately in order to estimate the behavior of soil structure. For estimation of K/sub 0/-value depending upon the stress history of dry sand, a new type of K/sub 0/-oedeometer apparatus is devised, and the horizontal earth pressure is accurately measured. For this study, 2 types of one-cyclic K/sub 0/-Loading/unloading models have been studied experimentally using four relative densities of the sand. The results obtained in this test are as follows : K/sub on'/ the coefficient of earth pressure at - rest for virgin loading is a function of the angle of internal friction Φ' of the sand and is determined as K/sub on/=1 - 0.914 sin Φ', K/sub ou'/ the coefficient of earth pressure at rest for virgin unloading is a function of K/sub on/ and over consolidation ratio(OCR), and is determined as K/sub ou/=K/sub on/(OCR)K/sup a/. The exponent α, increases as the relative density increases. K/sub or'/ the coefficient of earth pressure at rest for virgin reloading decreases in hyperbola type as the vertical stress, σ/sub v/’, increases. And, the stress path at virgin reloading leads to the maximum prestress point, independent upon the value of the minimum unloading stress. The gradient of this curve, m/sub r/ increases as OCR increases.