Fracture propagation and damage characterization of a soft coal seam subjected to shaped-charge blasting under in-situ stress
Year: 2026
Type: article
Abstract: Loosening blasting in coal seams offers low construction costs and high efficiency for permeability enhancement. However, in-situ stress inhibits the propagation of blast-induced fractures. Understanding how in-situ stress affects fracture propagation is therefore essential for optimizing blasting-based permeability enhancement. To investigate the temporal evolution of fracture propagation and the different responses of the crushing and fracture-propagation stages to increasing in-situ stress in soft coal, this study combined theoretical analysis with numerical simulation. The interaction between in-situ stress and shaped-charge blasting was analyzed, and fracture propagation under different in-situ stress levels was investigated. The mechanism by which in-situ stress suppresses fracture propagation in fractured coal was then clarified. Finally, the relative extent of coal failure during crushing-zone formation and subsequent fracture propagation was characterized using failed-element statistics under different in-situ stress levels. The results showed that when the vertical and horizontal stresses were equal, the circumferential stress was distributed in a regular circle and decreased with distance from the blasthole. In the absence of in-situ stress, fracture length increased nearly linearly. As the in-situ stress increased, the growth rate of the main fracture progressively decreased, and the transition from relatively rapid propagation to slower propagation occurred earlier. The final main-fracture length showed an overall nonlinear reduction with increasing in-situ stress, and fracture extension was strongly restricted under the higher stress conditions. This suppression is consistent with the increase in compressive confinement around the blasthole, which makes continued fracture opening and extension less favorable. In-situ stress had only a limited influence on the failed-element total during crushing-zone formation but substantially reduced the failed-element total during the fracture-propagation stage. The reduction during fracture propagation became progressively greater with increasing stress, with the smallest failed-element totals occurring in the 25–30 MPa cases. These variations represent stress-dependent trends within the investigated numerical conditions rather than universal critical stress thresholds. These results provide theoretical guidance for blasting-based permeability enhancement in deep coal seams.
Source: Scientific Reports
Authors: Guojian Cheng, Xingang Niu
Language: English
Topic: Rock Mechanics and Modeling
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,690
OpenAlex ID: W7225250262