Study on Mechanical Properties of Waste Gangue-Based Backfill Material for TBM Lining in Coal Mines

This study prepares backfill material for TBM segment lining using waste gangue as coarse ‎aggregate combined with cement mixed slurry. The research explores the variation in uniaxial ‎compressive strength under three curing periods (1d, 7d, 14d) with different water-cement ‎ratios and admixture proportions. Results show that waste gangue-modified bean gravel as ‎coarse aggregate extends the compaction stage, imparts good ductility, and significantly ‎improves compressive strength. Compressive strength increases steadily with extended curing ‎time. When admixtures are added in specific proportions, they effectively enhance early ‎strength and further increase peak compressive strength, achieving early strength and high ‎strength effects. After mixing with slurry, waste gangue forms an interactive reinforcement ‎effect through three key processes: gangue interlocking, bonding reinforcement, and ‎cementation solidification. During material compaction, the stress-strain curve sequentially ‎undergoes three stages: pore compaction, slip adjustment, and fracture reconstruction‎.