• Geotechnical Engineering
• /
• v.10 no.4
• /
• pp.167-180
• /
• 1994

A series of long term consolidation tests were conducted under loading -unloading and loading(pc) -unloading(p.) -reloading(p,) conditions using reconstituted clay in order to investigate the effect of stress history on secondary consolidation characteristics and the applicability of the secondary consolidation model suggested by Bjerrum to overconsolidated clays. According to the test results, the secondary compression settlement affected by the stress history in the first half of experimental period and the coefficient of secondary compression, C‥‥ is dependent on overconsolidation ratio, OCR(p,1 p.), maBium OCR (p./p.), and unloading duration time. Moreover the coefficient of secondary consolidation in the latter half of experimental period Cn is mainly affected by OCR and it gradually reduces with OCR increment. Finally the comparison of the experimental results with the Bjerrum model indicates that the Bjerrum model can be applied beyond certain range of stress history in the overconsolidated clay.

• Geotechnical Engineering
• /
• v.13 no.6
• /
• pp.25-36
• /
• 1997

A degree of consolidation at any time can be evaluated by using cone penetration test after soil improvement. In this case, after stopping the penetration of a piezocone, pore pressure dissipation(PPD) best is carried out until the pore pressure remains constant. Since the hydraulic conductivity of soft ground is very small, it takes very long time to finish the PPD test. This research is performed to develop a method overcoming this problem of the PPD test and reducing the test time. The analyses are carried out in the following ways : an equilibrium pore pressure can be determined by using pore pressure measured in the middle of the test, which is predicted by hyperbolic, Asaoka and Hoshino methods. And this equilibrium pore pressure is compared with the one measured in a test of long duration. As a result of the study, it is found that Hoshino method is the best way to predict the equilibrium pore pressure in a teat of short duration. And it is proposed as a methodology to fond a minimal time in which we can get an equilibrium pore pressure.

• Journal of Yeungnam Medical Science
• /
• v.33 no.2
• /
• pp.98-104
• /
• 2016

Background: Clinical differences in Mycoplasma pneumonia (MP) in children and adolescent patients according to abnormal infiltrate patterns on the chest X-ray were compared. Methods: From 2012 to 2015, patients (n=336) diagnosed with MP at Yeungnam University Medical Center have been classified as eiher lobar pneumonia or bronchopneumonia based on the infilterate patterns observed on chest X-ray. Cases were analyzed retrospectively for gender, age, seasonal incidence rate, main symptoms (fever duration, extrapulmonary symptoms), and laboratory results, including white blood cell count, hemoglobin, platelets, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), as well as concurrent respiratory virus infection. Results: The following results were observed. First, lobar pneumonia affected 22.0% of all MP patients and was the most common in preschool children, with a high incidence rate in November and December. Second, lobar pneumonia had a longer fever duration than bronchopneumonia (p<0.001), and also showed significantly higher platelets (336.8 vs. $299.1k/{\mu}L$, p=0.026), ESR (46.3 vs. 26.0 mm/hr, p<0.001) and CRP (4.86 vs. 2.18 mg/dL, p=0.001). Third, viral co-infection was more common in bronchopneumonia (p=0.017), affecting 66.7% of infants and toddlers (p=0.034). Finaly, lobar consolidation was most common in both lower lobes. Conclusion: MP in children has increased in younger age groups, and the rate of lobar pneumonia with severe clinical symptoms is higher in older children.

• Journal of Veterinary Clinics
• /
• v.20 no.3
• /
• pp.351-356
• /
• 2003

The aim of this experiment was to study the calcium sulfate on early bone consolidation in distraction osteogenesis in the canine mandible. Twelve dogs were used and divided into control group (group A, 4 heads), sodium hyaluronate injection group (group B, 4 heads), mixture of calcium sulfate and sodium hyaluronate injection group (group C, 4 heads). Each group were subdivided into 3 weeks testing group (totally 6 heads) and 5 weeks testing group (totally 6 heads). Mandibular distraction was started at the 5th day after the mandibular osteotomy and continued for 10 days by 1 mm a day. After the distraction on the 10th day of mandibular distraction, 0.5 m1 saline in group A, 0.5 m1 sodium hyaluronate in group B, and 0.5 ml mixture of calcium sulfate and sodium hyaluronate in group C were each injected in mandibular distraction lesion. And X-ray examination, bone mineral density, and histopathological findings were examined. The radiological findings were the most radiopaque in group C, and the most radiolucent in group A in both 3 and 5 week testing group. The level of bone mineral density was also the highest in group C, and the lowest in group C in both 3 and 5 week testing group. The histopathological findings of new bone formation were the most remarkable in group C in both 3 and 5 week testing group. New bone formation of group A was not present in both 3 and 5 week testing group. In conclusion, calcium sulfate is a kind of material that can stimulate early bone formation and can shorten the duration of bone consolidation. And it can be effective in clinical usage.

• Geomechanics and Engineering
• /
• v.18 no.2
• /
• pp.189-203
• /
• 2019

Brine leakage is a common phenomenon during construction facilitated by artificial freezing technique, threatening the stability of frozen wall due to the continual thawing of already frozen domain. This paper takes the frequently encountered soft clay in Wujiang District as the study object, and remolded specimens were prepared by mixing calcium chloride solutions at five levels of concentration. Both the deformation and pore water pressure of frozen specimens during thawing were investigated by two-stage loading tests. Three sections were noted from the changes in the strain rate of specimens during thawing at the first-stage load, i.e., instantaneous, attenuated, and quasi-stable sections. During the second-stage loading, the deformation of post-thawed soils is closely correlated with the dissipation of pore water pressure. Two characteristic indexes were obtained including thaw-settlement coefficient and critical water content. The critical water content increases positively with salt content. The higher water content of soil leads to a larger thaw-settlement coefficient, especially at higher salt contents, based on which an empirical equation was proposed and verified. The normalized pore water pressure during thawing was found to dissipate slower at higher salt contents, with a longer duration to stabilize. Three physical indexes were experimentally determined such as freezing point, heat conductivity and water permeability. The freezing point decreases at higher salt contents, especially as more water is involved, like the changes in heat conductivity. The water permeability maintains within the same order at the considered range of salt contents, like the development of the coefficient of consolidation. The variation of the pore volume distribution also accounts for this.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.6C
• /
• pp.321-329
• /
• 2008

In this study, a series of column test as a way in order to make up for the weakness point of the conventional acceleration method were conducted to both propose the suction board drain method and grapes the specific improvement character of this method as a result of a sort of plastic drain board and a phase of vacuum pressure conditions. On this occasion, the study focused on computing the effective factors of the fittest Suction board drain method affected by each condition through confirming the settlement generated during the test, the water content reduction and stress increase effect occurred arising from the test, and the ratio of consolidation related to the improvement period. In accordance with the shape of core and that whether the core is attached to the filter(pocket or adhesion), the castle type of adhesion and the column type of pocket are more efficient than the others as a consequence of the test to find out the improvement effect depending on each drainage such as a castle type, coil type, harmonica type, column type of pocket and a castle of the adhesion. In case of the step suction pressure, the shorter the period of $-0.8\;kg/cm^2$ as a final step of the suction pressure is, the better the improvement is. In addition, the correlation between degree of consolidation per each suction pressure level and duration of application was drawn as a curve and the point of inflection on this curve was provided to determine the duration period to maximize the consolidation.

• Journal of the Korean Geotechnical Society
• /
• v.15 no.4
• /
• pp.57-67
• /
• 1999

In conventional stability analysis of embankment on soft clay ground, an averaged undrained shear strength$(s_u)$ for the depth of clay layer is usually used. Also, all applied load is assumed to an immediate load for simplicity of analysis. The load in the field, however, increases gradually. Undrained shear strength increases during loading due to consolidation of clay ground. In this study, the stability analysis program(RSI-SLOPE) is developed. By using this program, it is possible to consider the rate of strength increase according to the elapsed time of consolidation and the depth of clay ground. And the rested duration for consolidation and gradually increased load can also be considered. Using the examples of some embankments, the critical embankment heights calculated by RSI-SLOPE program are compared with those by PCSTABL without the considerations of gradually increased load and rate of strength increase. In addition, this study contains analysis and comparison about the influence of coefficient of consolidation$(c_u)$ and drainage distance$(H_{DR})$ in the embankment design. RSI-SlOPE program may be useful for more effective and accurate embankment design.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.6
• /
• pp.183-193
• /
• 2003

Most construction works on the soft ground adopt instrumentation to manage settlement and stability of the embankment. The rapid progress of the information technologies and the digital data acquisition on the soft ground instrumentation has led to the fast-growing amount of data. Although valuable information about the behaviour of the soft ground may be hiding behind the data, most of the data are used restrictedly only for the management of settlement and stability. One of the critical issues on soft ground instrumentation is the long-term settlement prediction. Some observational settlement analysis methods are used for this purpose. But the reliability of the analysis results is remained in vague. The knowledge could be discovered from a large volume of experiences on the observational settlement analysis. In this article, we present a database to store settlement records and data mining procedure. A large volume of knowledge about observational settlement prediction were collected from the database by applying the filtering algorithm and knowledge discovery algorithm. Statistical analysis revealed that the reliability of observational settlement analysis depends on stay duration and estimated degree of consolidation.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.42
• /
• pp.68-77
• /
• 2000

Analyses, in which load was regarded as instant load and gradual step load, respectively, were performed with data measured on a gradually loaded field, and the results were inspected to find the effect of load conditions, and the final settlements which were predicted by Hyperbolic, Tan's, Asaoka's, and Monden's methods were compared with each other. Settlement curves in which load was regarded as instant load and gradual step load being to coincide at twice the time of duration of embankment. On the ground installed vertical drain, from the results of Hyperbolic, Tan's, Asaoka's, Monden's, Curve fitting I, and Curve fitting II (simple, carrillo) methods it was concluded that Asaoka, Curve fitting I, and Curve fitting II methods are reliable for prediction final settlement with back analysis.

• Tuberculosis and Respiratory Diseases
• /
• v.57 no.4
• /
• pp.381-385
• /
• 2004

Pulmonary gangrene is a rare and severe complication of bacterial pneumonia, where a pulmonary segment or lobe is sloughed due to parenchymal devitalization of the parenchyma, with secondary anaerobic infection and necrosis caused by pulmonary vascular thrombosis. Prior to the antibiotic era, massive pulmonary gangrene was potentially fatal. Herein, a case of pulmonary gangrene in a 67-year-old man is reported. He complained of fever, chills, dyspnea and purulent sputum of 5 days duration. The plain chest radiograph showed well-marginated right upper lobe consolidation, with bulging minor fissure, suggestive of a Klebsiella infection. A contrast CT scan demonstrated consolidation of the right upper lobe, with a central necrotizing portion. Klebsiella species was confirmed from both sputum and blood cultures. After appropriate antibiotics, the chest X-ray and CT scan 3 weeks later showed a large cavity with an air-fluid level, sloughing-off and extrusion of necrotic lung tissue, suggestive of pulmonary gangrene. Seven months later, the right gangrenous lung showed severe volume loss on a chest radiograph. The management of pulmonary gangrene has been somewhat controversial. Herein, it was managed without surgical drainage or resection. If the antibiotic therapy had failed, then a surgical approach would have been considered.