- 권한신청
- P-ISSN2233-8292
- E-ISSN2287-4747
- KCI
ISSN : 2233-8292
발파하중 시간이력 산정
Evaluation of blast load time series
박두희 (한양대학교)
신영완 (하경엔지니어링)
박인준 (한서대학교)
초록
폭발 시 순간적으로 발생하는 고온 및 고압가스는 공벽 주변의 암반을 파쇄하며 이로 인해 파쇄영역 외부에서는 진동형태의 에너지가 방사방향으로 전달된다. 이러한 발파가 인근 구조물 또는 사면에 미치는 영향을 살펴보기 위해서는 정밀한 발파하중을 적용한 동적 수치해석 모델이 요구된다. 일반적으로 발파 해석시 고온 고압 가스로 암반에 균열이 발생하는 과정은 모사하지 않으며 경험식을 통하여 산정된 발파하중을 파쇄영역의 경계면에 재하하여 진동의 전파를 모사하게 된다. 발파하중을 정확하게 산정하는 것은 발파 해석의 가장 중요한 요소이지만 이의 적절성을 시험발파로부터 도출된 발파진동 추정식과의 비교를 통하여 철저하게 검토한 사례는 제한적이다. 본 연구에서는 발파로 인하여 발생된 진동의 전파를 수치적으로 모사하였으며 시험발파 계측기록과의 비교를 통하여 발파하중 시간이력을 산정하였다. 진동을 방사방향으로 전파시키기 위하여 발파로 인한 파쇄영역을 가상의 원형으로 가정하여 모델링 하였으며 발파하중을 경계벽에 재하 하였다. 해석 결과, 발파하중의 전파 특성은 하중의 주파수와 지반 감쇠비의 영향을 크게 받는 것으로 나타났다. 또한, 국내외에서 널리 사용하는 발파 경험식을 터널의 발파 모사에는 적용하였을 경우 계산되는 진동속도가 현장 계측보다 크게 나타나 하중에 대한 보정과정이 필요한 것으로 나타났다. 보정된 발파하중이 적용된 수치해석을 수행한 결과 장약량에 무관하게 해석결과는 시험발파로부터 도출된 추정식과 잘 맞는 것으로 분석되었다.
- keywords
- 발파진동, 폭발하중, 파쇄영역, 진동감쇠, 수치해석, Blast vibration, Detonation pressure, Fracture zone, Attenuation, Numerical analysis
Abstract
During blasting, high temperature and pressure gas is instantaneously emitted, which results in fracture of rock mass. Outside the fractured zone, energy is transmitted in radial direction in the form of elastic waves. In this study, the fracturing process is not modeled. Instead, to simulate the propagation of blast induced vibration, the pressure load derived from empirical equations is applied to the fracture boundary. In the numerical modeling, accurate prediction of the blast load time series, including the detonation pressure, is most important. However, comprehensive study which evalutes the blast load from measured attenuation relationship is limited. In this study, the propagation of vibration due to explosion is simulated using numerical analysis and blast time series was back-calculated through comparison withthe measured record. To allow propagation of the vibration in radial direction, the fracture zone was modeled as a circle and pressure was applied normal to the boundary. The results show that the characteristics of blast vibration are highly dependent on the frequency of the load and the damping ratio of rock mass. In addition, it was found that the most widely used empirical function in Korea is not appropriate for modeling the blast inside the tunnel. In addition, it is shown that the detonatio pressure should be reduced by a significant amount from the empirical equation. When the adjusted load is applied, the results are in good agreement with the attenuation relationship derived from the measurements, regardless of the charge
- keywords
- 발파진동, 폭발하중, 파쇄영역, 진동감쇠, 수치해석, Blast vibration, Detonation pressure, Fracture zone, Attenuation, Numerical analysis
참고문헌
1. Choi, S.O., Park, E.S., Sun, W.C., Chung, S.K. (2004), “A Study on the blasting dynamic analysis using the measurement vibration waveform”, Journal of Korean Society for Rock Mechanics, Vol. 14, No. 2, pp. 108-120.
2. Choi, J.S., Lee, J.M., Jo, M.S. (2006), “A calculation of blasting load using input identification method & evaluation of structure's vibration in numerical analysis”, Journal of Korean Society for Rock Mechanics, Vol. 16, No. 3, pp. 232-240.
3. Itasca Consulting Group (2008), “FLAC (Fast Lagrangian Analyses of Continua) v.6.0”.
4. Jeon, S.S., Jang, Y.W., Jung, D.H. (2007), “Estimation of blasting distance satisfying allowable peak particle velocity - Analytical & Numerical analysis approach”, journal of KOSHAM, Vol. 7, No. 1, pp. 39-46.
5. Konya, C.J., Walter, E.J. (1991), Rock blasting and overbreak control, National Highway Institute, pp. 5.
6. Kramer, S.L. (1996), Geotechnical earthquake engineering, Prentice Hall, Upper Saddle River, N.J.,
7. Kuhlemeyer, R.L., Lysmer, J. (1973), “Finite element method accuracy for wave propagation problems”, Journal of Soil Mechanics & Foundations Div, Vol. 99, No. Tech Rpt.
8. Liu, Q., Tidman, P. (1995), “Estimation of the dynamic pressure around a fully loaded blast hole”:Retrieved from Canmet Mrl Experimental Mine.
9. Lysmer, J., Kuhlemeyer, R. (1969), “Finite element model for infinite media”, Journal of Engineering Mechanics Division. ASCE, Vol. 95, pp. 859-877.
10. Park, D.H., Cho, Y.G., Jeon, S.W. (2006), “A case study on the blasting analysis of slope using monitored vibration waveform”, Korean Society of Explosives & Blasting Engineering, Vol. 24, No. 2, pp. 41-50.
11. Park, D., Jeon, B., Jeon, S. (2009), “A numerical study on the screening of Blast-induced waves for reducing ground vibration”, Rock mechanics and rock engineering, Vol. 42, No. 3, pp. 449-473.
12. Park, D., Kim, T.G., Ahn, J.K., Park, I.J. (2013), “Amplification characteristics of mountain slope”, journal of KOSHAM, Vol. 13, No. 2, pp. 117-123.
13. Shin, J.H., Moon, H.G., Chae, S.E. (2011), “Effect of blast-induced vibration on existing tunnels in soft rocks”, Tunnelling and Underground Space Technology, Vol. 26, No. 1, pp. 51-61.
14. Starfield, A.M., Pugliese, J.M. (1968), “Compression waves generated in rock by cylindrical explosive charges: a comparison between a computer model and field measurements”, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts: Elsevier, 5, pp. 65-77.
15. Yang, H.S., Lim, S.S., Kim, W.B. (2003), “Tunnel blasting design with equations obtained from borehole and crater blasting”, Journal of Korean Geotechnical Society, Vol. 19, No. 5, pp. 327-333.
- 다운로드 수
- 조회수
- 0KCI 피인용수
- 0WOS 피인용수