• 한국지반공학회지:지반
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• 제10권4호
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• pp.167-180
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• 1994

사전압밀된 포화점토의 응력이력이 2차압밀특성에 미치는 영향 및 Bjerrum모델이 과압밀점토의 2차압밀침하추정에 적용가능한지를 실험적으로 파악하기 위하여 재성형점토를 이용하여 재하-제하 및 재하-제하-재재하 응력이력의 조건에서 일련의 장기압밀시험을 실시하였다. 실험결과에 의하면 과압밀점토의 2차압밀침하는 전반부에서 응력이력의 영향을 받고 전반부의 2차압밀계수 Cn은 OCR(선행 압밀하중 Pcy재재하하중 Pr), 최대 OCR(선행압밀하중 Pcy제 하시의 하중 Pu)과,제하시간에 의존하며 과압밀비 증가에 따라 감소한다. 또한 2차압밀후반부 의 2차압밀계수 C.2는 OCR의 영향을 받으며 과압밀비 증가에 따라 감소한다. 최종적으로 실험 결과와 Bjerrum모델을 비교분석한 결과 임의 응력이력범위를 벗어나면 과압밀점토에서 Bjerrum모델의 적용은 가능하다.

• 한국지반공학회지:지반
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• 제13권6호
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• pp.25-36
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• 1997

피에조콘을 이용하면 연약지반 개량후 임의의 시점에서 지반의 압밀도를 파악할 수가 있다. 이 경우 임의의 심도에서 피에조콘의 관입을 멈추고 간극수압이 일정한 값에 이를 때까지 간극 수압 소산시험을 실시하는데, 연약지반의 투수계수가 작기 때문에 대체적으로 상당히 오랜 시간 동안 소산시험을 하게 된다. 본 논문에서는 침하 분석기법 가운데 일반적으로 널리 알려져 있는 쌍곡선법, 아사오카법, 호시노법을 이용하여 간극수압 소산시험시의 평형간극수압을 각각 추정한 후 장시간에 걸친 실제 시험결과와 비교함으로써 간극수압 소산시험에 소요되는 시간을 단축할 수 있는 방법을 연구하였다. 그 결과, 호시노법을 이용한 추정방법이 가장 적합한 방법임을 알 수 있었으며 이를 이용한 효율적인 간극수압 소산시험 방법을 제시하였다.

• Journal of Yeungnam Medical Science
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• 제33권2호
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• pp.98-104
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• 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.

• 한국임상수의학회지
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• 제20권3호
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• pp.351-356
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• 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
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• 제18권2호
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• pp.189-203
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• 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.

• 대한토목학회논문집
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• 제28권6C호
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• pp.321-329
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• 2008

본 연구에서는 전통적인 압밀촉진공법의 단점을 보완하기 위한 방법으로 석션보드드레인 공법을 제안하고, 본 공법의 개량특성을 파악하기 위해, 배수재 종류 및 단계 진공압 조건에 따른 일련의 Column 실험을 실시하였다. 이때 실험 간 발생되는 침하량과 실험 종료 후 발생된 함수비 저감효과 및 강도증진효과를 파악하고, 개량 기간에 따른 압밀도를 파악하여 각 조건에 따른 최적의 석션보드드레인 공법 영향인자를 산정하고자 하였다. 각 배수재(포켓식 성곽형, 코일형, 하모니카 형, 원형 및 열융착식 성곽형배수재) 종류에 따른 개량 효과를 파악하기 위한 실험 결과, Core 형상(원형, 판형)과 필터의 Core 부착 여부(포켓식, 열융착식)에 의해 열융착식 성곽형 배수재와 포켓식 원형배수재의 배수효율이 다른 배수재의 경우 보다 좋게 나타났다. 단계석션압 조건 실험의 경우 최종 단계석션압인 $-0.8\;kg/cm^2$으로의 기간이 짧을수록 개량도가 크게 나타났다. 또한 각 석션압 단계 별 압밀도-적용기간 곡선 상의 변곡점을 이용하여 압밀효과를 극대화 시킬 수 있는 적용기간을 산정할 수 있었다.

• 한국지반공학회논문집
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• 제15권4호
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• pp.57-67
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• 1999

연약점토지반 위의 성토사면에 대해 안정해석을 수행할 경우, 종래에는 해석의 간편성 때문에 하중재하 형태를 순간재하로 가정하고, 점토층 깊이에 대해 평균적인 비배수전단강도$(s_u)$를 적용하여 해석해 왔다. 그러나 실제 현장의 하중재하 형태는 성토하중의 점증적 중가와 방치가 단계적으로 반복수행되는 형태이므로 점토지반의 압밀진행에 따른 비배수전단강도의 증가가 발생하게 된다. 본 연구에서는 정규압밀 상태인 연약점토지반 위의 점증성토와 방치기간을 고려할 수 있고, 또한 압밀경과시간과 점토지반의 깊이에 따른 강도증가율을 고려할 수 있는 안정해석 프로그램(RSI-SLOPE)을 개발하였다. 이 프로그램을 이용하여 임의로 가정한 해석단면에 대하여 성토설계를 수행하였고, 한계성토고에 대해서 강도증가율을 고려 않는 종래의 안정해석 프로그램의 결과와 비교하였다. 또한, 성토설계시 압밀계수$(c_u)$와 배수거리 $(H_{dr})$의 영향을 비교.분석하였다. 본 연구에서 개발된 강도증가율을 고려한 안정해석 프로그램(RSI-SLOPE)을 이용하면 계획된 성토고까지 최소허용안전율을 만족하면서 성토할 수 있는 성토완료기간을 구할 수 있기 때문에 효과적인 성토계획 및 설계가 가능할 것으로 생각된다.

• 한국농공학회지
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• 제45권6호
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• pp.183-193
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• 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.

• 한국농공학회지
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• 제42권
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• pp.68-77
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• 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
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• 제57권4호
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• pp.381-385
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• 2004

저자들은 클렙시엘라균종에 의한 폐렴에 동반된 폐 괴저를 수술적 치료없이 약물로만 호전시킨 1예를 경험하였기에 문헌고찰과 함께 보고하는 바이다.