Effects of Reinforcement of Steel Fibers on the Crack Propagation of Fissured Clays

균열점토의 균열진행에 대한 강섬유의 보강효과

  • 유한규 (정회원, 삼성건설 토목설계 ENG팀)
  • Published : 1994.09.01

Abstract

In order to assess the possibility of using steel fibers in the fissured ciays, uniaxial compression tests were performed on both unreinforced and reinforced clay samples containing a pre-existing crack. Test results showed that the steel fiber reinforcement increased resistance to cracks initiation and their propagation, and therefore increased both stress at crack growth initiation and peak stress at failure. The increase in resistance to cracks initiation and their propagation was related to the arresting or deflecting the crack propagation in clay samples by steel fibers. A theoretical interpretation of experimental results was made using fracture mechanics theory and pull-out mechanisms in fiber reinforced materials. It was revealed that the steel fibers had bridging effect through their pull-out action that caused an increased resistance to the propagation of the cracks in the samples. The predicted pull-out force based on theoretical analyses agreed reasonably well with the measured values obtained from pull-out tests.

균열점토에 대한 강섬유 사용 가능성을 평가하기 위하여 균열이 있는 보강점토와 비보강점토 시료에 대한 일축압축실험을 실시하였다. 실험결과 강섬유 보강으로 인하여 균열의 시작과 진행에 대한 저항력에 증가하므로써 균열 시작시 응력과 파괴시 극한응력이 증가되었다. 균열의 시작과 진행에 대한 저항력의 증가는 점토시료에서 강섬유에 의한 균열진행의 억제 또는 진행방향의 변경과 관련되어 있음을 알 수 있었다. 파괴역학 이론과 섬유로 보강된 물질에서의 일반미케니즘을 적용하여 실험결과에 대한 이론적인 해석이 이루어졌다. 해석결과 강섬유의 인발작용을 통한 연결효과로 인하여 시료에서 균열의 진행에 대한 저항력이 증가됨을 알 수 있었다. 이론적인 분석에 의하여 예측된 인발력은 인발실험으로 부터 산정된 값과 비교적 잘 일치되었다.

Keywords

References

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