Effect of Air Position to the Mechanism of Air-Decked Blasting

Abstract:

Based on the JHC model of concrete damage evolution, the dynamic stress characteristics and failure mechanism of blast-hole near-field about different air-decked charge structures are studied by numerical simulation. Result shows that the failure mechanism of typical elements changes from compression-shear failure into shear-tensile failure gradually with the increase of their position in indirect initiation of both top-air-decked and bottom-air-decked charges, because of the affecting factors of the freedom and the loading from the hole. If middle-air-decked charges detonate from the top and bottom at the same time, loading and unloading waves in blasting hole are more influential to the damage of bottom elements than the surface freedom, because detonation waves of both top and bottom meet at the middle hole, so it is conducive to the media failure at the bottom hole, the elements of freedom surface have the same failure properties to top-air-decked charge.

• Periodical: Advanced Materials Research (Volumes 328-330)
• Pages: 1167-1171
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.328-330.1167
• Online since: September 2011
• Authors: Liang Wu
• Keywords: Air-Decked, Dynamic Stress, Engineering Blasting, Numerical Simulation

References

[1] Melnikov and Marchenkov. Effective Methods of Application of Explosion, 12th U. S. Symposium on Rock Mechanics (New York, AIME), Chap. 18, (1971), p.359.

[2] P. Terrett, S.A. Steyn and A.J. Rorke, Air decking at Duvha, a technical evaluation. Proc. Sixth high-tech Seminar, State-of-the-Art Blasting Technology Instrumentation and Explosives Applications, Boston Massachusetts, USA, ( 1995), p.587.

[3] L.Q. Liu, P.D. Katsabanis. Numerical modeling of the effects of air decking/decoupling in production and controlled blasting. Rock Fragmentation by Blasting, (1996), p.319.

DOI: 10.1201/9781003078104-46

[4] Z.D. Liu, Y.H. Gao, Y.H. Tan. Study on the test of bottom-air-decked charge structure in Nanfen open Iron . Express Information of Mining Industry, Vol. 385 (2002)No7, p.13. (In Chinese).

[5] B. Li. Applications of air-decked charge technology in Waitoushan open Iron. Metal Mine, Vol. 326(2003) No8, p.59. (In Chinese).

[6] L. Wu, H.B. Zhu, W. B Lu. An overview and discussion of the study on air-decking blasting. Engineering blasting, Vol. 15 (2009) No1, p.49. (In Chinese).

[7] Holmquist T J, Johnson G R. A computational constitutive model for concrete subjected to larger strains, high strain rates and high pressure. Jackson. N, Dickert S. 14th International Symposium Ballistics. USA: American Defense Preparedness' Association, (1995).

[8] LSTC, LS-DYNA keyword user's manual. California: Livermore Software Technology Corporation, (2003).

[9] X. Xia, H.B. Li, J.R. Li. Numerical simulation of blast-induced cracks in rock. Rock and Soil Mechanics, Vol. 27(2006) No. 11 , p.1987. (In Chinese).