Blasting, Volume. 42, Issue 2, 44(2025)

Experimental Study on Crack Propagation Characteristics of Blasting-Induced Fracturing in Low-permeability Coal Samples

ZHANG Fei-yan1,2, DUAN Xiao-yan1, and HAN Ying3,4,5、*
Author Affiliations
  • 1College of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China
  • 2Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Jiaozuo 454003, China
  • 3School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China
  • 4Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region (Henan Province), Jiaozuo 454003, China
  • 5Science and Technology R&D Platform of Emergency Management Ministry for Deep Well Ground Control and Gas Extraction Technology, Jiaozuo 454003, China
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    Pre-split blasting has emerged as a crucial technique for enhancing the permeability of low-permeability coal seams and improving gas drainage efficiency. While extensive research has focused on the effects of factors such as blast hole configuration, charge structure, charge coefficient, explosive quantity, and the propagation dynamics of blasting stress waves, limited attention has been given to fracture expansion characteristics through numerical simulations. Furthermore, experimental investigations into crack propagation remain scarce. This study addresses these gaps by examining low-permeability coal samples from a specific mine, employing small-dose coupled charge blasting technology combined with computerized tomography scanning technology. The experimental approach enabled the acquisition of macroscopic damage characteristics and three-dimensional crack distribution patterns post-blasting, facilitating an in-depth analysis of internal crack expansion under blasting stress. Key findings demonstrate the feasibility of utilizing detonating explosives instead of conventional explosives for small-scale coal sample blasting experiments with low-dose coupled charges. The results reveal that: (1) a larger blast hole diameter correlates with diminished crack propagation and permeability enhancement under constant charge quantity and tamping pressure; (2) tamped charges outperform loose charges when blast hole diameter and charge quantity are held constant; (3) an optimal charge quantity exists for fracture propagation, with excessive amounts proving counterproductive. Specifically, for the standard-sized low-permeability coal samples examined, a charge quantity of 25 mg yielded optimal results, producing a crack volume ratio of 12.79% and a single crack volume of 20 135.03 mm, followed closely by a 20 mg charge.

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    ZHANG Fei-yan, DUAN Xiao-yan, HAN Ying. Experimental Study on Crack Propagation Characteristics of Blasting-Induced Fracturing in Low-permeability Coal Samples[J]. Blasting, 2025, 42(2): 44

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    Paper Information

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    Received: Feb. 28, 2025

    Accepted: Jun. 24, 2025

    Published Online: Jun. 24, 2025

    The Author Email: HAN Ying (hyhpu@hpu.edu.cn)

    DOI:10.3963/j.issn.1001-487x.2025.02.005

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