Explosives and Blasting (화약ㆍ발파)

Korean Society of Explosives and Blasting Engineering (대한화약발파공학회)
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Blast Modeling of Concrete Column Using PFC

PFC를 이용한 콘크리트기둥의 발파모델링

  • Published : 2005.03.01
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Abstract

An explosion modeling technique was developed by using the spherical discrete element code, $PFC^{3D}$, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a $PFC^{3D}$ particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). A test blast was conducted for a RC column, whose dimension was $600\times300\times1800$ in millimeters. The initial velocities of the surface movements were measured to be in the range of $14\~18\;m/s$ with the initiation times of $1.5\~2.0m$. Then the blasting procedure was simulated by using the modeling technique. The particle assembly representing the concrete was made of cement mortar and coarse aggregates, whose mirco-properties were obtained from the calibration processes. As a result, the modeling technique developed in this study made it possible for the burden to move with the velocity of $17\~24\;m/s$, which are slightly higher values compared to those of the test blast.

본 연구에서는 $PFC^{3D}$를 사용하여 시멘트 모르타르와 굵은 골재로 이루어진 콘크리트 기둥의 발파과정에서 나타나는 폭발과 파괴현상을 모사하여 보았다. 폭원모델링 과정에서는 공내입자들의 반경을 팽창/수축시키는 기법을 통해 공벽입자들에 접촉력의 형태로 폭발압력을 부여하는 방법을 사용하였다. 현장 발파실험에서는 철근콘크리트 기둥을 대상으로 초안폭약을 사용하여 발파하고 그 파괴거동을 고속카메라를 이용하여 관찰하였다. 모사과정에서는 철근의 규격과 입자요소의 크기에 따른 해석시간을 고려하여 모르타르와 굵은 골재로 이루어진 콘크리트 기둥을 대상으로 제안된 폭원모델링 기법을 적용하여 해석을 실시하였다. 해석결과 나타난 저항선의 이동속도는 $17\~24\;m/s$로서 실험치 $14\~18\; m/s$를 약간 상회하고 있으나 제안된 폭원모델링 기법을 사용한다면 암석이나 기타 재료들에 대한 발파과정에서 나타는 파괴거동을 수치적으로 보다 유사하게 모사할 수 있을 것으로 판단된다.

Keywords

References

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