Surrounding rock control technology for fully mechanized top-coal caving entries in residual thick coal seam

SHAO Chunrui; JI Tingxiu; SUN Jianning; ZHAO Baoyou

doi:10.11799/ce202509009

Abstract：To address the challenge of controlling surrounding rock stability in entries of fully mechanized top-coal caving faces in residual thick coal seams,a support strategy for roadways passing through goaf was proposed,integrating"grouting and backfilling of the pre-driven goaf+grouting reinforcement of fractured roof and ribs+W-steel strap bolting and meshing+combined steel arch support and shotcreting".The effectiveness of this strategy was validated through theoretical analysis,numerical simulation,and field practice.Research results indicate that:the grouting backfill body can form a reconstructed roof and solid rib,not only providing essential conditions for the safe passage of the entry through the goaf but also effectively supporting and reinforcing the fractured roof of the goaf,eliminating potential safety hazards of roof falls in the entry;grouting reinforcement of the roof and coal rib within the influence zone of the goaf enhances the strength and integrity of the fractured surrounding rock,improves the anchoring performance of bolts(cables),and optimizes the load-bearing state of the bolts(cables)and steel arches;the shotcreting seal measure not only prevents weathering of the backfill body and fractured coal mass but also further enhances the surface protection capacity of the gateway surrounding rock.Field application demonstrates that the developed combined support technology of"backfilling+grouting+W-steel strap bolting and meshing+arch support+shotcreting"can meet the requirements for safely driving and supporting the entry through the goaf and for the safe extraction of the residual thick coal seam.