Tests for blasting induced crack propagation characteristics of short-delay blasting

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Journal of Vibration and Shock ›› 2017, Vol. 36 ›› Issue (24) : 97-102.

YANG Renshu1, 2, DING Chenxi1, YANG Guoliang1, YANG Liyun1, WANG Yanbing1

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Abstract

Using the model material of PMMA, adopting the new type test system of digital laser dynamic caustics, the blasting induced main crack propagation characteristics of short-delay blasting with time delay of 20μs and 40μs were studied. Failure modes and destruction process discrepancies of specimens were compared. Time histories of blasting induced main crack deflection angle, propagation speed, dynamic stress intensity factor and other physical quantities were analyzed. Results showed that vertical off-set value of blasting induced main crack with time delay of 20μs is obviously larger than that with time delay of 40μs; time delay value has little effect on the first peak of blasting induced main crack’s dynamic intensity factor, but has a remarkable effect on the second peak; furthermore, homodromous and abreast detonation of two or more grooved boreholes makes propagation of blasting induced main crack deviate from grooving direction, and then affects effects of directional fracture, this case should be avoided as much as possible.

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short-delay blasting / blasting induced main crack / propagation speed / dynamic stress intensity factor / directional fracture

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YANG Renshu1, 2, DING Chenxi1, YANG Guoliang1, YANG Liyun1, WANG Yanbing1. Tests for blasting induced crack propagation characteristics of short-delay blasting[J]. Journal of Vibration and Shock, 2017, 36(24): 97-102

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