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Slit tube responses and rock fracture characteristics in slit charge blasting under high in situ stress
AbstractDeep mining of natural resources, like coal, is increasingly utilizing directional blasting technology with slit charge for rock blasting at greater depths. This study, based on numerical simulation methods, analyzes the dynamic behavior of slit charge blasting in three aspects: slit tube dynamic response, hoop stress evolution, and crack propagation. According to research findings, the failure mode of the slit tube mainly manifests as a tensile fracture of the inner wall and a shear fracture at the end connection, where the end connection of the slit tube is the weak point of the overall structure. The dynamic response of the slit tube mainly exhibits radial response in the vertical direction of the slit and hoop response in the slit direction. The hoop tensile stress plays a crucial role in determining the spread of cracks caused by explosions. As the in situ stress increases, the peak hoop tensile stress reduces, and the peak hoop compressive stress increases. This hinders the propagation of cracks. In addition, the directional impact is most pronounced in the middle of the borehole, with the longest primary directional crack observed. Conversely, the directional impact is least favorable near the bottom of the borehole. When the in situ stress reaches 60 MPa, the purpose of directional fracture has not been achieved, suggesting combining presplit blasting for in situ stress relief to improve rock breaking efficiency.
Highlights Based on the numerical simulation method, the influence of the dynamic response of the slit tube itself structure of slit charge blasting on the effect of directional blasting was investigated. The effect of circumferential stress on the expansion of directional main cracks was analyzed under a high in situ stress environment. The effects of different in situ stress conditions on the expansion of directional main cracks and crack distribution were analyzed.
Slit tube responses and rock fracture characteristics in slit charge blasting under high in situ stress
AbstractDeep mining of natural resources, like coal, is increasingly utilizing directional blasting technology with slit charge for rock blasting at greater depths. This study, based on numerical simulation methods, analyzes the dynamic behavior of slit charge blasting in three aspects: slit tube dynamic response, hoop stress evolution, and crack propagation. According to research findings, the failure mode of the slit tube mainly manifests as a tensile fracture of the inner wall and a shear fracture at the end connection, where the end connection of the slit tube is the weak point of the overall structure. The dynamic response of the slit tube mainly exhibits radial response in the vertical direction of the slit and hoop response in the slit direction. The hoop tensile stress plays a crucial role in determining the spread of cracks caused by explosions. As the in situ stress increases, the peak hoop tensile stress reduces, and the peak hoop compressive stress increases. This hinders the propagation of cracks. In addition, the directional impact is most pronounced in the middle of the borehole, with the longest primary directional crack observed. Conversely, the directional impact is least favorable near the bottom of the borehole. When the in situ stress reaches 60 MPa, the purpose of directional fracture has not been achieved, suggesting combining presplit blasting for in situ stress relief to improve rock breaking efficiency.
Highlights Based on the numerical simulation method, the influence of the dynamic response of the slit tube itself structure of slit charge blasting on the effect of directional blasting was investigated. The effect of circumferential stress on the expansion of directional main cracks was analyzed under a high in situ stress environment. The effects of different in situ stress conditions on the expansion of directional main cracks and crack distribution were analyzed.
Slit tube responses and rock fracture characteristics in slit charge blasting under high in situ stress
Deep Underground Science and Engineering
Sui, Zhe (author) / Yang, Liyun (author) / Wu, Lijun (author) / Ding, Chenxi (author)
2025-01-26
Article (Journal)
Electronic Resource
English
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