터널 발파설계 최적화를 위한 실험 및 수치해석적 접근

Experimental and Numerical Approach foy Optimization of Tunnel Blast Design

  • 발행 : 2003.04.01

초록

화약폭발로 발생한 응력파 전파특성을 파악하기 위하여 화약종류, 장약조건, 전파매질조건 별로 실내 모형시험 및 현장 암반시험과 수치해석을 시행하였다. 수치해석은 시험조건과 동일한 조건을 모델링하여 시행하였다. 2공을 동시 발파하는 경우에 2공 중심에서 응력크기는 1공 발파보다 2배정도로 증가되었다. 최대응력 도달시간은 디커플링장전조건이 밀장전조건보다 2배정도 지연되어서 가스압력에 의해 최대 응력이 발생하였다. 시험결과와 수치해석결과를 비교.분석한 결과 수치해석결과가 시험결과보다 약간 저평가되었지만 비교적 유사하여 수치해석으로 발파결과를 미리 예측할 수 있었다. 도로터널의 일반적인 발파패턴도에 대하여 수치해석을 시행하고 외곽공과 외곽공과 인접한 확대공 발파로 인하여 발생하는 동적 암반거동 및 암반손상을 평가하였다. 수치해석결과 확대공의 손상영역이 외곽공보다 크게 나타났다. 확대공 손상영역을 감소시키기 위하여 낮은 밀도의 화약사용, 디커플링장전, 확대공과 외곽공사이의 거리 증가 등의 방안을 제안하였다.

Laboratory model blast and in-situ rock blast tests were conducted to determine blast-induced stress wave propagation characteristics under different explosive types, different loading conditions and different mediums. Dynamic numerical approaches were conducted under the same conditions as experimental tests. Stress magnitudes at mid-point between two blast holes which were detonated simultaneously increased up to two times those of single hole detonation. The rise time of maximum stress in a decoupled charge condition was delayed two times that of a fully charged condition. Dynamic numerical analysis showed almost similar results to blast test results, which verifies the effectiveness of numerical approaches fur optimizing the tunnel blast design. Dynamic numerical analysis was executed to evaluate rock behavior and damage of the contour hole, the sloping hole adjacent to the contour hole in the road tunnel blasting pattern. The rock damage zone of the sloping hole from the numerical analysis was larger than that of the contour hole. Damage in the sloping hole can be reduced by using lower density explosive, by applying decoupled charge, or by increasing distance between the sloping hole and the contour hole.

키워드

참고문헌

  1. PENTAGON-2D User Manual, 2002 release EmeraldSoft Co., Ltd.
  2. Int. J. Rock. Mech. Min. Sci. & Geotech. Continuum Modelling of Explosive Fracture in Oil Shale Grady, D.E.;Kipp, M.E.
  3. The Dynamics of Explosion and its Use Henrych, J.
  4. Spectra and Analysis Kharkvich, A.A.
  5. Ph.D. Thesis, Korea University Quantitative Assessment of Blast Waves and Numerical Approach for Tunnel Blasting Optimization Kim, S.G.
  6. MS. Thesis, Korea University Experimental Approaches on Estimation of Damage Zone due to Blaet Loading Kweon, J.W.
  7. Int. J. Rock. Mech. Min. Sci. v.34 no.5 A Numerical Study of the Effcets of Accurate Timing on Rock Tramentation Liu, L.;Katsabanis, P.D.
  8. Last Shock Hugoniot Data Marsh, S.R.
  9. Int. J. Rock Mech. Min. Sci. & Geotech, Abstr. v.11 Fragmentation of Rock under Dynamic Loads Shockwy, D.A.;Curran, D.R.;Seaman, L. Rosenberg, J.T.;Petersen, C.F.
  10. Rock Mech. Rock Eng. Finite Element Analysis of Vibration Induces by Propatating Waves Generated by Tunnel Blasting Valliappan, S.;Ang, K.K.
  11. Rock Fracture Mechanics Principles, Design and Applications Whittaker, B.N.;Singh, R.N.;Sun, G.
  12. Explosion and their Applicaion Zhand, Baopiing(et al.)
  13. Int. J. Rock. Min. Sci. v.37 no.7 Applicability of Mohr-Coulomb and Hoek-Brown Strength Criteria to the Dynamic Strength of Brittle Rock Zhao, J.