Dynamic caustic experiment on fracture behaviors of flawed material induced by pre-notched blasting

Yang Renshu; Xu Peng; Yang Liyun; Chen Cheng

doi:10.11883/1001-1455(2016)02-0145-08

Volume 36 Issue 2

Oct. 2018

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Yang Renshu, Xu Peng, Yang Liyun, Chen Cheng. Dynamic caustic experiment on fracture behaviors of flawed material induced by pre-notched blasting[J]. Explosion And Shock Waves, 2016, 36(2): 145-152. doi: 10.11883/1001-1455(2016)02-0145-08

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Yang Renshu, Xu Peng, Yang Liyun, Chen Cheng. Dynamic caustic experiment on fracture behaviors of flawed material induced by pre-notched blasting[J]. Explosion And Shock Waves, 2016, 36(2): 145-152. doi: 10.11883/1001-1455(2016)02-0145-08

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Dynamic caustic experiment on fracture behaviors of flawed material induced by pre-notched blasting

doi: 10.11883/1001-1455(2016)02-0145-08

Yang Renshu^{1, 2},
Xu Peng^{1
,
,},
Yang Liyun¹,
Chen Cheng²

1.
School of Mechanics & Civil Engineering, China University of Mining & Technology, Beijing 100083, China
2.
State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining & Technology, Beijing 100083, China

Received Date: 2014-08-13
Rev Recd Date: 2014-10-08
Publish Date: 2016-03-25

Abstract

Abstract

Using a digital laser dynamic caustics experimental system, the fracture behavior of blast-induced cracks in flawed materials under both ordinary borehole and pre-notched borehole were studied. The results show that the main crack propagating along the pre-notched direction is 10 μs earlier than that along the non-notched direction, which attributes the blast energy release along with the pre-notched direction. The initiation toughness and average speed of the main crack in the pre-notched direction is 0.58 MN/m^3/2 and 277 m/s, respectively, corresponding to 54% and 86% of the ordinary blasting. For the pre-notched blasting, The space is large enough for the detonation gas expansion, when the main crack goes through with the pre-crack, and the detonation gas energy moving to the both ends of the pre-crack, leading mainly mode Ⅰ type initiation fracture of the wing crack, with which its mode Ⅰ dynamic stress intensity factor stays between 0.6 MN/m^3/2 and 0.8 MN/m^3/2 during 60-250 μs, which forms an obvious platform in the histories of mode Ⅰ dynamic stress intensity factor, and the decrease rate of wing crack velocity are also delayed. Eventually, the duration time of the crack propagation and the crack length are increased by 22.7% and 17.8%, respectively, compared with the ordinary borehole blasting.
- mechanics of explosion,
- dynamic fracture behavior,
- dynamic caustics experiment,
- flawed material,
- pre-notched blasting,
- crack propagation

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References(14)

References

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