• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 암반역학위원회 학술세미나 논문집
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• pp.165-193
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• 2003

The Han River tunnel connecting Yoido and Mapo was constructed as a part of the Seoul subway line No.5, which is 52 km long, to improve the traffic conditions of Seoul. It is constructed 15.6∼30m below the river floor. It Is the first under-river tunnel in Korea with the length of 1,288m. Geological conditions of the ground under the Han River were more complex and irregular than expected at the design stage, because there were several faults, fracture zones and slickensided joints coated with graphite. It was thus indispensable to estimate the ground condition of the tunnel face to apply proper excavation and reinforcement methods. Advance borings and face mappings were performed before excavation to improve constructional efficiency and excavation stability.

• 복합신소재구조학회 논문집
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• 제3권2호
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• pp.28-35
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• 2012

Recently, there is to increase interest in seismic performance of piers. Hollow section is applied to increasing the seismic performance of piers. However, hollow RC pier becomes the biaixial confining state because hollow part is not confined. The pier is developed brittle failure from inner face in hollow part. A tube is inserted in hollow part to become the weakness. This is ICH RC(Internally Confined Hollow RC) pier. This pier is enhanced stiffness, strength, and ductility by core concrete has triaxial confining stress. In this paper is researched about parameters effect the seismic performance. Parameters are hollow ratio, transverse reinforcement, longitudinal reinforcement, and concrete strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.126-129
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• 2006

A bending moment $M_u$ transferred at slab-column connection is resisted at the slab critical section by flexure and shear. The ACI 318-05 Building Code(1) gives an empirical equation for the fraction ${\gamma}_{\upsilon}$ of the moment $M_u$ to be transferred by shear at the slab critical section at d/2 from the column face and also the effective wide(c+3h). The equation is based on tests of interior slab-column connections without shear reinforcement. In order to investigate the data eight test specimens were examined. The test shows that increased slab load substantially reduces both the unbalanced moment capacity and the lateral drift capacity of the connection. Especially, the specimens with the bottom reinforcement existence and nonexistence, appears remarkable differences. Studies also show that the code equation for ${\gamma}_{\upsilon}$ does not apply to all cases. The purpose of this study is to compare the test results with present ACI 318-05 Building Code provisions for design of slab-column connections and with the analysis of the experimental data for a new limitation of strength equation without shear reinforcement and bottom reinforcement.

• 대한간호학회지
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• 제34권3호
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• pp.440-448
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• 2004

Purpose: This study was to evaluate the effects of a physical activity reinforcement program on exercise compliance, depression, and anxiety in continuous ambulatory peritoneal dialysis(CAPD) patients. Method: A nonequivalent control group with a pre-post test was designed. Data collection was done from December, 2002 to June, 2003 at a hoapital. The degree of depression and anxiety of the patients was assessed by the score of SCL-90-R, and exercise compliance was measured by exercise period, frequency, time and intensity. The experimental group was composed of 19 participants who were educated based on an exercise education protocol and carried out walking exercises two to four times a week after hearing verbal persuasion biweekly through the telephone or a face-to-face interview for 12 weeks, while 17 participants in control group received no intervention. Result: 1. The experimental group showed significant improvement in self-efficacy of exercise compliance (U=79.00, p=.01), exercise period ($x^2$=20.84, p=.00), exercise frequency ($x^2$=9.03, p=.0l), exercise time ($x^2$=9.03, p=.0l) and exercise intensity ($x^2$=11.09, p=.00) compared to those of the control group. 2. The experimental group showed a lower depression score (U=84.50, p=.01) than the results of the control group. 3. However, there were no changes in anxiety level compared to the control group. Conclusion: The physical activity reinforcement program was found to have an effect on exercise compliance and the depression score of CAPD patients. The results provided evidence for the importance of physical activity and verbal persuasion in CAPD patients.

• 터널과지하공간
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• 제15권2호
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• pp.102-110
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• 2005

익산-장수 고속도로 ○ ○ 공구에 위치한 ○ ○ 터널 저토피 계곡구간에서 시공 중 붕락이 발생하였다. 본 구간은 TSP 탐사 및 시추조사 등을 통해 불연속면이 예측되었으나, 굴착 중 실제 암질이 비교적 양호하고 막장이 안정되어 암반 등급을 상향 변경하여 시공하였다. 그러나 굴착 중 발파와 동시에 붕락이 발생하였으며, 터널 막장 상부 8 m 부분의 붕락과 함께 지상 구간의 침하에 따른 계곡수 및 지하수 유입으로 진행되었다. 붕락구간 복구를 위해 붕락원인 분석, 보강공법의 선정 및 3차원 터널 안정성 해석을 실시하였고, 막장 상부 공동부는 팽창성 경량 콘크리트로 충진 후, 강관다단 그라우팅 공법으로 안정화시키고, 터널 상부 지반 침하부에서는 계곡수로 이설 후, 시멘트밀크 그라우팅 공법에 혼용된 약액 그라우팅 공법으로 지반보강 및 차수를 실시하였다.

• Structural Engineering and Mechanics
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• 제69권4호
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• pp.439-455
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• 2019

This research deals with thermo-electro-mechanical buckling analysis of the sandwich nano-beams with face-sheets made of functionally graded carbon nano-tubes reinforcement composite (FG-CNTRC) based on the nonlocal strain gradient elasticity theory (NSGET) considering various higher-order shear deformation beam theories (HSDBT). The sandwich nano-beam with FG-CNTRC face-sheets is subjected to thermal and electrical loads while is resting on Pasternak's foundation. It is assumed that the material properties of the face-sheets change continuously along the thickness direction according to different patterns for CNTs distribution. In order to include coupling of strain and electrical field in equation of motion, the nonlocal non-classical nano-beam model contains piezoelectric effect. The governing equations of motion are derived using Hamilton principle based on HSDBTs and NSGET. The differential quadrature method (DQM) is used to calculate the mechanical buckling loads of sandwich nano-beam as well as critical voltage and temperature rising. After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as various HSDBTs, length scale parameter (strain gradient parameter), the nonlocal parameter, the CNTs volume fraction, Pasternak's foundation coefficients, various boundary conditions, the CNTs efficiency parameter and geometric dimensions on the buckling behaviors of FG sandwich nano-beam. The numerical results indicate that, the amounts of the mechanical critical load calculated by PSDBT and TSDBT approximately have same values as well as ESDBT and ASDBT. Also, it is worthy noted that buckling load calculated by aforementioned theories is nearly smaller than buckling load estimated by FSDBT. Also, similar aforementioned structure is used to building the nano/micro oscillators.

• 대한토목학회논문집
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• 제26권4C호
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• pp.255-264
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• 2006

터널 시공시 지반상황이 불량하거나 불확실한 지질정보로 인한 붕락사고를 방지하기 위하여 지보재와 병용하여 터널보조공법을 사용한다. 현재 보조공법에 관련된 전문가 시스템은 인공신경망, 퍼지추론 등의 연구가 진행되었고 터널 기술자에게 보조공법을 결정하는데 많은 도움을 주고 있는 상황이나 보조공법을 결정하는데 있어 정량적인 평가항목을 정하는데 어려움이 많은 것으로 파악되고 있다. 따라서, 본 연구에서는 사회과학, 의료, 금융, 농업 등 다양한 분야에 걸쳐 데이터분석에 이용되는 데이터마이닝 기법을 공학분야에 적용시켜 보조공법 설계자료를 바탕으로 보조공법의 의사결정 규칙을 추론하고 PDA를 적용한 전문가 시스템을 구축하였다.

• 터널과지하공간
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• 제11권4호
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• pp.328-338
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• 2001

Fiber Glass Tube(FGT) 또는 steel pipe를 이용한 터널막장의 수평보강공법 그리고 강관다단공법 등은 터널 굴착시 터널막장의 안정성이 확보되지 못할 경우에 흔히 사용된다. 그러나 이러한 공법이 사용된 터널의 역학적 거동은 아직 충분히 알려진 바가 없으며, 따라서 설계와 전산해석 과정에서 경험에 의존하는 경우가 많고 공법의 합리적인 적용이 어려운 실정이다. 본 연구에서는 복합체 역학을 이용한 보강공법의 전산해석 단순화 방법의 적용성을 검증하였고, 강화지반의 등가탄성계수는 평균장 이론과 변형률 에너지 이론을 사용하여 도출하였다. 다양한 보강패턴에 따른 터널막장의 거동에 관한 매개변수 연구를 수행하였다.

• 한국터널지하공간학회 논문집
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• 제4권3호
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• pp.185-193
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• 2002

본 연구에서는 풍화토층에 굴착된 지하철 터널의 변형거동과 종방향 지보재의 보강효과가 3차원 유한차분해석에 의해 조사되었다. 굴착방법이 터널 변형거동에 미치는 영향을 조사하기 위해서 반단면 및 전단면의 2가지 굴착방법이 고려되었다. 또한, 우산형 막장보강법 (RPUM) 및 유리섬유 파이프의 보강효과가 비교되었다. 터널 변형거동을 분석하기 위해 막장변위, 내공변위, 선행변위 및 측벽변위가 조사되었고, 굴착방법 및 종방향 지보재의 효과가 지표침하량를 사용하여 분석되었다. 해석 결과, 반단면 굴착이 전단면 굴착 보다 더 큰 내공변위, 선행변위, 측벽변위를 야기시키며, 반면 막장변위는 전단면 굴착이 반단면 굴착에 비해 더 크게 발생됨을 알았다. 또한, 같은 굴착방법에서는 RPUM만이 사용되었을 때가 RPUM이 유리섬유 파이프와 같이 사용되었을 때 보다 모든 변위가 더 켜졌다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.68-71
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• 2004

In the shear strengthening with FRP sheets, beams are wrapped around the webs and tension face of critical shear span by fiber sheets. The shear strength of RC beam strengthened with FRP sheets must be calculated based on the effective strain that can be developed in the FRP sheets at ultimate stage because the final failure modes of beams are governed by premature debonding of FRP sheet due to the limitation of bonded length by beam depth. An experimental study is carried out to evaluate the shear strengthening effect of AFRP or GFRP sheets with respect to shear reinforcement ratio of rebar. From the test results, it was found that the additional shear strength provided by GFRP or AFRP can be estimated by $p_w{\cdot}f_w$ based on the maximum effective strain of FRP sheet $4,000m{\mu}$ proposed by ACI 440 committee.