Research on the mechanism of rockburst induced by mined coal-rock linkage of sharply inclined coal seams

Abstract

In recent years, the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased. Local deformation of mining coal-rock results in frequent rockbursts. This has become a critical issue that affects the safe mining of deep, steeply inclined coal seams. In this work, we adopt a perspective centered on localized deformation in coal-rock mining and systematically combine theoretical analyses and extensive data mining of voluminous microseismic data. We describe a mechanical model for the urgently inclined mining of both the sandwiched rock pillar and the roof, explaining the mechanical response behavior of key disaster-prone zones within the deep working face, affected by the dynamics of deep mining. By exploring the spatial correlation inherent in extensive microseismic data, we delineate the “time–space” response relationship that governs the dynamic failure of coal-rock during the progression of the sharply inclined working face. The results disclose that (1) the distinctive coal-rock occurrence structure characterized by a “sandwiched rock pillar-B₆ roof” constitutes the origin of rockburst in the southern mining area of the Wudong Coal Mine, with both elements presenting different degrees of deformation localization with increasing mining depth. (2) As mining depth increases, the bending deformation and energy accumulation within the rock pillar and roof show nonlinear acceleration. The localized deformation of deep, steeply inclined coal-rock engenders the spatial superposition of squeezing and prying effects in both the strike and dip directions, increasing the energy distribution disparity and stress asymmetry of the “sandwiched rock pillar-B₃₊₆ coal seam-B₆ roof” configuration. This makes worse the propensity for frequent dynamic disasters in the working face. (3) The developed high-energy distortion zone “inner–outer” control technology effectively reduces high stress concentration and energy distortion in the surrounding rock. After implementation, the average apparent resistivity in the rock pillar and B₆ roof substantially increased by 430% and 300%, respectively, thus guaranteeing the safe and efficient development of steeply inclined coal seams.

Keywords

steeply inclined coal seam / localized deformation / mechanism of induced rockburst / prevention and control of rockburst

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