• Title/Summary/Keyword: 균열제어

Search Result 451, Processing Time 0.025 seconds

A Study on the Thermal Crack Control of Tunnel Lining Concrete due to the Overbreak (과다 여굴에 따른 터널 라이닝콘크리트의 온도균열 제어 연구)

  • 장동일;채원규;조광현;김광일;손영현
    • Proceedings of the Korean Institute of Industrial Safety Conference
    • /
    • 1998.05a
    • /
    • pp.215-220
    • /
    • 1998
  • 터널공사에서는 지산의 강도에 따라 선정된 굴착공법을 이용하여 굴착 된 단면에는 굴삭된 터널의 안전과 시공상 능률을 증진시키고, 장기간에 걸친 터널의 사용에 대한 충분한 신뢰성을 갖추기 위하여 지지공$\cdot$라이닝콘크리트 등이 설치된다. (중략)

  • PDF

Crack analysis of mis-matched welding at CRDM(control rod drive mechanism) upper penetration nozzles of RPV(reactor pressure vessel) considering the change of mechanical properties (기계적 물성 변이를 고려한 원자로 압력용기(RPV : reactor pressure vessel) 상부 제어봉 구동 장치(CRDM : control of rod diver mechanism) 관통 노즐 이종재 용접부의 균열해석)

  • Lee, Yong-U;Kim, Jong-Seong;Lee, Gang-Yong
    • Proceedings of the KWS Conference
    • /
    • 2005.06a
    • /
    • pp.241-243
    • /
    • 2005
  • PDF

A Study on Controlling of Cracks Occurred at Crown of Tunnel Concrete Lining using Model Test (모형 실험에 의한 터널 콘크리트 라이닝의 천단부 균열 제어에 관한 연구)

  • Jeon, Joong-Kyu;Jeon, Chan-Ki;Kim, Nag-Young;Kim, Su-Man;Lee, Jong-Eun
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.8 no.3
    • /
    • pp.227-235
    • /
    • 2006
  • The problematic issue of cracking, water shedding in tunnel is recently coming out in the view of the structural stability. Hence, the assessment is required for the existing tunnels to achieve the structural soundness of tunnels, and their safety and maintenance. In this study, fracture behaviour and displacement of a tunnel concrete lining using steel fiber reinforcement concrete was investigated. The specimens were fabricated in single lining for a model of real road tunnel. As parameters, load condition, thickness of lining, whether or not rear cavity in crown, and a ratio of steel fiber in concrete were taken. From these factors, the load for crack and fracture, displacement, and the pattern of crack were looked into for the structural stability of a tunnel concrete lining.

Influence of Inadequate Rebar Lap Position on Crack of Underground Box Slab (철근 겹침이음 위치 부적정이 지하박스 슬래브 균열 발생에 미치는 영향)

  • Choi, Jung-Youl;Jang, In-Soo;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
    • /
    • v.6 no.4
    • /
    • pp.685-692
    • /
    • 2020
  • In this study, the experimental and analytical study were performed on the location of longitudinal cracks in the middle of underground box structures. The location where the longitudinal cracking occurred was investigated that the overlapping joint of the rebar and the section of maximum tensile stress generated. Using the finite element analysis, the strength reduction ratio of the rebar was estimated by lack of overlap joint length. As the result of adequacy investigation for the length of the overlap joint presented in the design criteria, it was analytically proved that the lack of the overlap joint length could be cause the decreasing cross-sectional force and concrete cracking. As the result of this study, the adequacy of the overlapping criterion in the current design criteria was confirmed based on the finite element analysis and actual field case. In the case of overlapping joints installed in inappropriate position, it was considered that a long term crack control would be need to ensure the sufficient safety factor for the designed cross-sectional force.