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영구동토 급속안정화를 위한 롤타입강재매트의 모델링과 해석(I)
문도영(Do Young Moon),강재모(Jae Mo Kang),이장근(Janggeun Lee),이상윤(Sang Yoon Lee),지광습(Goangseuo Zi) 한국지반신소재학회 2014 한국지반신소재학회 논문집 Vol.13 No.4
본 논문에서는 표준트럭하중을 받는 연약지반에 놓인 롤타입 강재매트의 모델링과 해석을 수행하였다. 롤 타입 강재매트는 접근성이 제한된 동토지역에서 손쉬운 현장운반을 위해 원형으로 접을 수 있는 강재매트를 의미하며, 동토지반의 융해로 형성되는 연약지반을 통과하는 비포장도로의 급속보강을 위해 개발되었다. 해석 모델은 강재매트 연결부의 비선형적 거동특성을 모사할 수 있는 연결요소, 강재매트의 휨강성을 갖는 쉘요소, 지반특성을 고려한 스프링 구속으로 구성된다. 또한 각 해석요소들의 구조적 거동은 각 모델링 단계에서 실험과 해석을 통해 검증되었다. 링크요소가 없는 빔과 쉘 요소해석이 수행되었으며, 본 연구에서 제시된 해석모델의 결과와 비교하였다. 해석결과, 본 연결부를 고려한 쉘 해석모델의 수직 처짐 결과가 다른 모델에 비하여 상당히 큰 것으로 확인되었다. 따라서, 느슨한 모래지반에 놓인 롤 타입 강재매트의 해석모델은 면밀한 변수해석 연구에 근거하여야 함을 알 수 있다. Finite element modelling and analysis were conducted for the roll-type steel mats which were placed on loose sand and subjected to a standard truck wheel load in this study. The roll-type steel mats mean that the steel mats can be folded as a circle shape for the carrying to fields in cold regions where workability is limited and are developed for a rapid rehabilitation method for roadway across soft ground which is caused by thawing during the summer season in cold regions. The model is composed of link elements to simulate nonlinear behavior of connections between steel mats, thick shell elements to have flexural stiffness of the steel mats, and springs to simulate characteristics of foundation soils. The structural behaviors of the shell, link elements, and springs were verified at each modelling step through experiment and analysis. Beam and shell analysis without the link elements were conducted and compared to results obtained from the model presented in this study. Significant vertical displacement is shown in the shell model with hinge connections. Therefore, the results demonstrate that the analysis model for the roll-type steel mats on loose sand needs further detail parametric studies.
관절내 종골 골절의 전산화 단층 촬영에 따른 분류 및 치료
강재도,김형천,김진형,Kang, Jae-Do,Kim, Hyung-Chun,Kim, Jin-Hyung 대한족부족관절학회 2001 대한족부족관절학회지 Vol.5 No.1
Purpose: To analyze the results of conservative or surgical treatment after computed tomograhy(CT) classification in intraarticular calcaneal fractures. Materials and methods: From January 1996 to May 1999, we prospectively analyze 23 cases of intraarticular calcaneal fractures who were treated conservatively or operated by open reduction and internal fixation by extensive L-shaped lateral approach after CT classification. Results: A functional scoring system of 0-100 points which was based upon the responses to AOFAS Ankle-Hindfoot Scale for the operative group was at 82.8, compared with 73.2 for the non-operative group, and these were meaningful statistically(P<0.05). Of type I fracture, in the operative group there were 2 excellent results and in the non-operative group there were 2 excellent results, 1 good result. or type II fractures, in the operative group there were 2 excellent results, 3 good results, 1 fair result and in the non-operative group there were 1 good result, 1 fair result, 2 poor results. Of type III fractures, in the operative group there were 2 fair results, 2 poor results and in the non-operative group there were 1 fair result, 3 poor results. Bohler angles of subtalar joint were changed from initial average $13.3^{\circ}$ to postoperative average $20.9^{\circ}$ for the operative group compared with from initial average $15.5^{\circ}$ to follow-up average $14.8^{\circ}$ of the non-operative group(P<0.01). Conclusions: Computed tomography in the evaluation of intraarticular calcaneal fractures is effective tool. We believed that open reduction and internal fixation in all Crosby & Fitzgibbons type II and according to degrees of comminution reducible type III for the intraarticular calcaneal fractures is more effective method than conservative treatment.