Long directional hole fracturing technology for preventing rock burst

This study addresses the issue of rockbursts in thick and hard roof strata triggered by mining activities by proposing long-hole staged hydraulic fracturing technology, and the effectiveness of which was validated through numerical simulation and field trials. To gain a deeper understanding of the mechanical mechanisms of this technology, a macro–micro dual-scale model was constructed, integrating mesoscale solid rock units and cohesive units to simulate macroscopic rock mass fracturing and the cohesive effects at the interfaces of localized hydraulic fracturing areas. Based on this model, numerical simulations of the surrounding rock fracture evolution induced by face advance under the condition of roof staged hydraulic fracturing were conducted. The results indicate that, compared to the untreated scenario, the staged hydraulic fracturing technology significantly altered the stress distribution characteristics of the roof, transforming periodic peak stresses into an oscillating-uniform-low stress distribution pattern, thereby effectively disrupting the integrity of the hard rock layers of the roof and blocking stress transfer pathways and energy transfer. Furthermore, analysis using the concept of shear stress confirmed that the technology can significantly reduce the impact of face advance and periodic roof collapses on the surrounding stress field, fundamentally eliminating the conditions for the formation of “suspended roof” structures. Field trial results from the 6303 working face further validated the practical application value of the technology. Trial data showed a significant reduction in high-energy microseismic events and an increase in low-energy events within the fractured area, indicating that the technology successfully reduced the risk of rockbursts. In summary, this study provides an innovative solution for the safe mining of mines under complex geological conditions.