Fracture-controlled stress redistribution and energy dissipation in coal seams induced by borehole destressing

High in-situ stress is a primary driver of coalburst-related engineering failures in deep coal mining, and borehole destressing is widely applied as a practical mitigation measure. Coalbursts represent a stress-driven engineering failure caused by excessive accumulation of elastic strain energy in coal seams. However, many existing studies describe stress relief qualitatively or rely on geometric indicators that do not explicitly characterise failure initiation, failure-zone evolution, or failure-suppression capacity under varying geological and stress conditions. This study develops a two-dimensional plane-strain numerical modelling framework to quantitatively investigate borehole-induced stress redistribution, failure development, and destress radius in high-stress coal seams. The model is verified against published field observations by comparing the destress radius across multiple borehole diameters, showing good agreement within acceptable engineering error limits. A systematic parametric analysis is conducted to evaluate the influence of borehole diameter, coal seam strength, burial depth, horizontal-to-vertical stress ratio, and seam dip angle on stress redistribution and the evolution of the failure zone. Results demonstrate that borehole diameter exerts the strongest control on vertical stress unloading, failure initiation and outward propagation of the failure zone, whereas horizontal stress response is comparatively less sensitive. Higher stress magnitude and lower coal strength accelerate failure development and enlarge the stress-relief zone, whereas increasing stress ratio and seam dip create asymmetric failure methods that reduce effective relief in fundamental directions. From an energy-based perspective, the observed reduction in stress concentration corresponds to a decrease in stored strain energy surrounding the borehole, indicating suppression of coalburst-related failure mechanisms. The findings provide design-relevant guidance for borehole destressing as a failure-mitigation strategy in high-stress coal mine layouts, where control of failure extent and burst potential is a primary engineering objective.