• 한국터널지하공간학회 논문집
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• 제13권1호
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• pp.33-50
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• 2011

최근 기존 도로의 확장에 대한 요구와 논의가 많아지고 있어 도심지와 산악지에 위치한 기존 터널의 확장에 대한 관심 또한 증가하고 있다. 터널 확장 계획 시에는 기존 터널을 최대한 활용한 시공방법과 안정성의 확보 방안에 대한 연구 및 고찰은 필수적이다. 본 연구에서는 시공 중인 2차로 도로터널의 3차로 확장 설계 내용을 이용하여 터널 확장시 주요 고려사항인 선형 계획, 터널 확장 방안, 굴착 방법, 보강계획 등을 제안하였다. 본 연구를 통하여 향후 터널 확장 설계시 보다 나은 기술적인 접근을 위한 방향제시 및 기술 향상을 도모할 수 있을 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1382-1387
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• 2010

A 3D FEM numerical analysis was performed to observe the changes of supporting system of a old 1-lane tunnel when it is enlarged to 2-lane, 3-lane and 4-lane. The standard Type-III supporting pattern was applied to the new tunnel because the ground was assumed as Type-III. The observation was carried out at the middle supporting system of the old 1-lane tunnel alignment. The results shows that the changes of old tunnel supporting system began when the new tunnel was excavated at 2D(D is the equivalent diameter of 1-lane tunnel) behind of the observation place and became very rapid from 1D.

• 한국터널지하공간학회 논문집
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• 제9권3호
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• pp.241-250
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• 2007

운영 중에 있던 기존터널을 확폭하는 터널공사를 수행하던 중 기존터널 시공 시 생성된 것으로 추정되는 과대여굴 및 대규모 공동이 발견되어 신설터널의 안정성문제가 대두되었다. 이러한 과대여굴 및 공동의 형성 원인은 기존터널 시공 시 불충분한 지반조사 상태에서 과도한 발파시공으로 인해 형성된 것으로 추정된다. 따라서 본 연구에서는 기존터널을 안전하게 확폭하기 위한 과대여굴과 공동의 처리 대책을 제시하였다.

• Journal of Chest Surgery
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• 제23권1호
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• pp.192-200
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• 1990

The results of conventional operative resection of diffuse subaortic stenosis[tunnel subaortic stenosis] have been less than satisfactory. We have performed modified Konno operation to enlarge the outflow tract of both ventricle with a patch in three patients with diffuse tunnel subaortic stenosis in the department of Thoracic and Cardiovascular Surgery, Seoul National University Children`s Hospital. Preoperative left ventricular aortic pressure gradients were 135 mmHg, 50 mmHg, 80 mmHg respectively in these patients. After right ventriculotomy, the septotomy was done and extended beyond the limit of the stenosis and fibrous and/or muscular tissue was removed from each edge of septal incision. After adequate widening of the tunnel subaortic stenosis with various patches, right ventricle was closed primarily or with prosthetic patches successfully. One patient who was diagnosed as complete atrioventricular septal defect had complete AV block preoperatively and was implanted permanent pacemaker, and others who were sinus rhythm preoperatively have no serious postoperative rhythm disturbance. One patient developed mild postoperative aortic insufficiency and one who had preoperative aortic insufficiency has still same grade of aortic insufficiency after operation. All had good postoperative hemodynamics without any postoperative residual pressure gradient.

• Advances in aircraft and spacecraft science
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• 제4권2호
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• pp.145-167
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• 2017

The presented paper gives an overview of several projects addressing the experimental characterization and control of the buffet phenomenon on 3D turbulent wings in transonic flow conditions. This aerodynamic instability induces strong wall pressure fluctuations and therefore limits flight domain. Consequently, to enlarge the latter but also to provide more flexibility during the design phase, it is interesting to try to delay the buffet onset. This paper summarizes the main investigations leading to the achievement of open and closed-loop buffet control and its experimental demonstration. Several wind tunnel tests campaigns, performed on a 3D half wing/fuselage body, enabled to characterize the buffet aerodynamic instability and to study the efficiency of innovative fluidic control devices designed and manufactured by ONERA. The analysis of the open-loop databases demonstrated the effects on the usual buffet characteristics, especially on the shock location and the separation areas on the wing suction side. Using these results, a closed-loop control methodology based on a quasi-steady approach was defined and several architectures were tested for various parameters such as the input signal, the objective function, the tuning of the feedback gain. All closed-loop methods were implemented on a dSPACE device able to estimate in real time the fluidic actuators command calculated mainly from the unsteady pressure sensors data. The efficiency of delaying the buffet onset or limiting its effects was demonstrated using the quasi-steady closed-loop approach and tested in both research and industrial wind tunnel environments.

• 터널과지하공간
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• 제26권2호
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• pp.131-142
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• 2016

본 연구에서는 채수율 향상을 목적으로 채굴공동의 대형화를 계획하는 주방식 하이브리드 채광법이 적용되고 있는 갱내 석회석 광산에 대해 갱내절리면 조사, 시추코어 분석, 암석물성시험 등을 통해 굴착손상영역의 범위와 물성의 변화양상을 실험적으로 규명하였으며, 이를 불연속체 수치해석에 직접 반영하여 대형 채굴공동의 안정성을 분석하였다. 채굴공동이 대형화할수록 굴착손상영역의 영향은 커질 수 있음이 확인되었으며 이를 통해 굴착손상영역을 제어할 수 있는 고정밀의 발파패턴이 대안으로 제시되었다.

• Wind and Structures
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• 제20권4호
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• pp.549-564
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• 2015

The three-dimensional unsteady incompressible Reynolds-averaged Navier-Stokes equations and k-${\varepsilon}$ double equations turbulent model were used to investigate the effect on the measurements of anemometers due to a passing high-speed train. Sliding mesh technology in Fluent was utilized to treat the moving boundary problem. The high-speed train considered in this paper was with bogies and inter-carriage gaps. Combined with the results of the wind tunnel test in a published paper, the accuracy of the present numerical method was validated to be used for further study. In addition, the difference of slipstream between three-car and eight-car grouping models was analyzed, and a series of numerical simulations were carried out to study the influences of the anemometer heights, the train speeds, the crosswind speeds and the directions of the induced slipstream on the measurements of the anemometers. The results show that the influence factors of the train-induced slipstream are the passing head car and tail car. Using the three-car grouping model to analyze the train-induced flow is reasonable. The maxima of horizontal slipstream velocity tend to reduce as the height of the anemometer increases. With the train speed increasing, the relationship between $V_{train}$ and $V_{induced\;slipstream}$ can be expressed with linear increment. In the absence of natural wind conditions, from the head car arriving to the tail car leaving, the induced wind direction changes about $330^{\circ}$, while under the crosswind condition the wind direction fluctuates around $-90^{\circ}$. With the crosswind speed increasing, the peaks of $V_X,{\mid}V_{XY}-V_{wind}{\mid}$ of the head car and that of $V_X$ of the tail car tend to enlarge. Thus, when anemometers are installed along high-speed railways, it is important to study the effect on the measurements of anemometers due to the train-induced slipstream.