Numerical Study of Fracture Process on Full-Scale Concrete Foundations by Means of Controlled Blast Method Utilizing Galvanized Steel Charge Holders

Abstract:

Mechanical breakage systems are generally employed to demolish a portion of a concrete building, however it is time consuming and costly. And the mechanical demolition work involves various risks such as those associated with occupational safety and presents a noise hazard to the general public living in the vicinity. Therefore, alternative methods for such work have been sought. For this purpose, a dynamic breakage system utilizing diamond-shaped charge holders was proposed to rapidly remove the desired portion of the concrete foundation. The charge holders which initiate crack growth were placed inside a concrete mass along the desired fracture plane. In this study, full-scale blast experiments utilizing the charge holders were introduced and the roughness of fracture planes was observed using a 3-dimensional photography system. In order to verify the effect of the charge holders on fracture controlling in full-scale blast experiments, the fracture processes of the concrete blocks were analyzed using the dynamic fracture process analysis (DFPA) code. The mechanism required to achieve controlled breakage was discussed after taking into account the influence of various loading conditions and crack tip velocity. It was found that the DFPA tool is a useful instrument in the analysis of full scale blast experiments.

• Periodical: Key Engineering Materials (Volume 744)
• Pages: 152-162
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.744.152
• Online since: July 2017
• Authors: Hak Man Kim, Daisuke Fukuda, Katsuhiko Kaneko, Yuich Nakamura, Ju Hyung Lee, Sang Ho Cho*
• Keywords: Concrete Foundation, Crack Propagation, Dynamic Breakage System, Dynamic Fracture Process Analysis (DFPA), Loading Condition

References

[1] W. L. Fourney, J. W. Dally, D. C. Holloway, Controlled blasting with ligamented charge holders, Int. J. Rock Mech. Mining Sci. Geomech. 15(3) (1978) 121-129.

DOI: 10.1016/0148-9062(78)90006-2

[2] Y. Nakamura, Model experiments on effectiveness of fracture plane control methods in blasting, Fragblast, 3(1) (1999) 59-78.

DOI: 10.1080/13855149909408034

[3] Y. Nakamura, S. H. Cho, M. Yoneoka, M. Yamamoto, K. Kaneko, Model experiments on crack propagation between two charge holes in blasting, Sci. Tech. Energ. Mater. 65 (2004) 34-39.

[4] K. Kaneko, Y. Matsunaga, M. Yamamoto, Fracture mechanics analysis of fragmentation process in rock blasting. Sci. Tech. Energ. Mater. 56 (1995) 207-215.

[5] M. Yamamoto, T. Ichijo, T. Inaba, K. Morooka, K. Kaneko, Experimental and theoretical study on smooth blasting with electronic delay detonators. Fragblast, 3(1) (1999) 3-24.

DOI: 10.1080/13855149909408030

[6] S. H. Cho, M. Nishi, M. Yamamoto, K. Kaneko, Fragment size distribution in blasting. Mater. Trans. 44(5) (2003) 951-956.

DOI: 10.2320/matertrans.44.951

[7] S. H. Cho, Y. Ogata, K. Kaneko, Strain rate dependency of the dynamic tensile strength of rock. Int. J. Rock Mech. Mining Sci. 40(5) (2003) 763-777.

DOI: 10.1016/s1365-1609(03)00072-8

[8] S. H. Cho, K. Kaneko, Influence of the applied pressure wave form on the dynamic fracture processes in rock. Int. J. Rock Mech. Mining Sci. 41 (2004) 771-784.

DOI: 10.1016/j.ijrmms.2004.02.006

[9] S. H. Cho, B. Mohanty, M. Ito, Y. Nakamiya, S. Owada, S. Kubota, Y. Ogata, A. Tsubayama, M. Yokota, K. Kaneko, Dynamic fragmentation of rock by high-voltage pulses. Int. Proceedings of 41st US symposium on rock mechanics, Curran Associates, Inc., (2006).

[10] S. H. Cho, Y. Nakamura, B. Mohanty, H. S. Yang, K. Kaneko, Numerical study of fracture plane control in laboratory-scale blasting. Eng. Fract. Mech. 75(13) (2008) 3966-3984.

DOI: 10.1016/j.engfracmech.2008.02.007

[11] D. Fukuda, K. Moriya, K. Kaneko, K. Sasaki, R. Sakamoto, K. Hidani, Numerical simulation of the fracture process in concrete resulting from deflagration phenomena. Int. J. Fract. 180(2) (2012) 163-175.

DOI: 10.1007/s10704-013-9809-4

[12] Y. Nakamura, M. Kato, Y. Ogata, I. Yamaura, S. Nakamura, S. H. Cho, Dynamic fragmentation method using simple-type charge holder for fracture control in blasting. 10th Japan Society of Civil Engineers symposium, Japan, (2010), pp.117-120.

[13] W. I. Duvall, Strain-wave shapes in rock near explosions. Geophys. 18(2) (1953) 310-323.

DOI: 10.1190/1.1437875

[14] I. Ito, K. Sassa, On the mechanism of breakage by smooth blasting. J. Mining Metallurg. Inst. Japan, 84 (1968) 1059-1065.

[15] M. A. Meyers, Dynamic Behavior of Materials. John Wiley and Sons, (1994), pp.488-566.

[16] L. Ma, L. Wu, L. C. Guo, On the moving Griffith crack in a nonhomogeneous orthotropic strip, Int. J. Fract. 136 (2005) 187-205.

DOI: 10.1007/s10704-005-6023-z

[17] A. Hillerborg, Analysis of a single crack, In, Fracture Mechanics of Concrete, Elsevier, Amsterdam, Netherlands, (1983), pp.223-249.

[18] K. Sato, H. Awayama, T. Hashida, H. Takahashi, Determination of strain-softening curve and fracture toughness of granite, Trans. Japan Soc. Mech. Eng. Series A, 56(526) (1990) 1400-1405.

DOI: 10.1299/kikaia.56.1400

[19] B. N. Whittaker, R. N. Singh, G. Sun, Rock fracture mechanics, Design and Application. Elsevier, (1992).

[20] K. Ravi-chandar, Dynamic Fracture, Department of Aerospace Engineering and Engineering Mechanics, The University of Texas, Elsevier, USA (2004).