• 한국농공학회논문집
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• 제54권1호
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• pp.19-26
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• 2012

Soils exhibit creep behavior in which deformation and movement proceed under a state of constant stress or load. In this study, A series of triaxial tests were performed under constant principal stress in order to interpret the undrained creep characteristics of silty sands. Although samples are non-plastic silty sands, the results of tests show that the creep deformation increasing over time. Based on the results of test, Singh-Mitchell model parameters and Generalized model coefficients were calculated. Generalized model showed slightly larger deformation in the primary creep range but secondary creep deformation was almost identical. Although Singh-Mitchell model showed relatively large errors compared to Generalized model because it uses the average of test results, but Singh-Mitchell model can be easily represented by three creep parameters.

• 한국농공학회논문집
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• 제55권5호
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• pp.9-16
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• 2013

This study finds the characteristics of long-term settlement of Bottom Ash and to review the application of Singh-Mitchell creep equation and Burgers Model to the creep behavior of Bottom Ash. In the undrained state, it was confirmed that creep behavior appeared in the range to 30-80 % of the maximum deviator stress by applying condition in other three stresses through triaxial compression test after isotropically consolidation. By using sieve analysis, it was compared to each sample that was passed through 9.5 mm, 2 mm, 0.25 mm sieves. Also, using Singh-Mitchell creep equation and Burgers Model, it was compared between the theoretical behavior and the observed behavior for each sample. In the result, it is found that creep behavior of Bottom Ash is similar to the theoretical behavior of Singh-Mitchell creep equation and Burgers Model in early stage and it is possible to predict creep behavior of Bottom Ash by these models.

• 한국농공학회논문집
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• 제51권6호
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• pp.69-76
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• 2009

Soils exhibit creep behavior in which deformation and movement proceed under a state of constant stress or load. In Korea, weathered soil is abundant and occupies around one-third of the country. Weathered soil is visually described as a sandy or gravelley soil, but the behavior is quite different from the behavior of usual sand and gravel. In particular, the permeability of weathered soil is similar to sand, but the durability of settlement is similar to clay. Therefore analysis of time-dependent behavior of weathered soil is very important. In this study, Creep tests with weathered soils were carried out under constant principal stress differences of various stress levels which were experimentally obtained by triaxial compression test. The results of these tests showed the creep behavior for which the deformation increased with time, and the results are consistent with phenomenological model by creep equation of Singh-Mitchell.

• 한국지반공학회논문집
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• 제27권1호
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• pp.65-76
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• 2011

본 논문에서는 보강토 구조물의 장기거동에 관한 수치해석 내용을 다루었다. 본 연구는 사용연한동안 지속하중을 받는 보강토 구조물의 장기 변형 관련 메카니즘을 고찰하는데 주 목적을 두었다. 연구를 위해 먼저 Singh-Mitchell 크리프 모델과 멱함수(Power law) 크리프 모델을 이용하여 각각 뒤채움흙과 보강재의 크리프 변형을 모델링하는 방안을 구축하였으며 이를 토대로 뒤채움흙과 토목섬유 보강재의 크리프 특성에 대한 매개변수 연구를 수행하였다. 해석결과 외부하중을 받는 보강토 구조물이 세립분이 많이 포함되어 있는 흙으로 뒤채움이 될 경우 뒤채움흙과 토목섬유 보강재로부터 발생하는 크리프 효과로 인해 상당한 크기의 장기 변형이 발생할 수 있는 것으로 나타났다. 본 논문에서는 외부하중을 받는 보강토 구조물에 있어서 크리프 효과가 구조물의 사용성에 미치는 영향을 집중적으로 고찰하였다.

• Clinics in Shoulder and Elbow
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• 제27권1호
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• pp.3-10
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• 2024

Background: Gunshot-related fractures near the elbow are challenging, and available data to guide the practitioner are lacking. This report analyzes injury patterns and treatment strategies in a case series from a high-volume urban trauma center. Methods: All periarticular gunshot fractures near the elbow treated at a level 1 trauma center from 2014 to 2018 were retrospectively reviewed. Fracture location, patient demographics, concomitant injuries, treatment modalities, and complications were analyzed. Results: Twenty-four patients were identified. All patients received prophylactic antibiotics upon admission and underwent urgent surgical debridement. Open reduction and internal fixation (ORIF) was performed with initial debridement in 22 of 24 patients. Seven patients sustained distal humerus fractures, 10 patients sustained isolated proximal ulna or proximal radius fractures, and seven had combined fracture patterns. Eleven patients presented with nerve palsy, and two had transected nerves. Two patients had vascular injury requiring repair. One patient required a temporary elbow-spanning external fixator and underwent staged debridement followed by ORIF. One patient with a grade IIIC fracture developed a deep infection that precluded ORIF. One patient required revision ORIF due to fracture displacement. Conclusions: This investigation reports on management of ballistic fractures near the elbow at a busy urban level I trauma center. Our management centered on rapid debridement, early definitive fixation, and intravenous antibiotic administration. We report on associated neurovascular injury, bone loss, and other challenges in this patient population. Level of evidence: IV.

• 한국지반공학회지:지반
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• 제14권5호
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• pp.129-142
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• 1998

본 연구에서는 파괴강도이내의 일정하중 상태에서 장기적으로 진행되는 연약지반의 침하특성을 파악하기 위하여 Creep 변형성분을 고려한 구성방정식을 유도하고, 유한요소해석 프로그램을 개발하여 이를 바탕으로 토공구조물의 장기적인 변형을 합리적으로 예측함으로서 연약지반상 토공구조 물의 설계 및 시공관리에 기여하고자 하였다. 점성토의 탄.소성거동을 표현하기 위해 Modified Cam Clay모델이 사용되었으며, Creep변형을 계산하는데 있어서는 체적 Creep요소를 고려할 경우 2차 압밀계수 C,를 적용하였고, 축차 Creep요소를 고려할 경우 Singh & Mitchel Creep경험식을 통한 m, a, A 상수를 이용한 것으로 개발된 프로그램의 신뢰성을 검증하기 위하여 이론해 및 실험치와 비교하였고, 적용된 각 상수들의 민감도 를 분석한 결과, 개발된 프로그램은 적용성이 좋은 것으로 판단되었다. 또한 국내외 2개의 현장에 적용한 결과, 제방의 변형해석에 있어 Creep을 고려하지 않은 경우보다 Creep을 고려한 경우가 오차가 적게 나타나고 체적 Creep만을 고려한 경우는 약간 과소평가되 고 축차 Creep까지 고려한 경우는 약간 과대평가됨을 알 수 있었다. 따라서 Creep정수를 얻기 위한 실험기의 개발, 적정 토질정수의 선택 등 향후에도 지속적인 연구가 요구된다.