Energy evolution and damage characteristics under different unloading rates of cemented backfill: after the influence of curing temperature

Deep mine filling mining disturbs the cemented gangue-fly ash backfill (CGFB) with high ground temperature and unloading, which causes internal damage and bearing performance degradation, threatening its long-term stability. CGFB energy evolution law and damage mechanism under high ground temperature and unloading circumstances must be investigated. The study examined CGFB's energy evolution curve, peak energy characteristics, linear energy storage law, energy conversion characteristics, and unloading damage at various temperatures (20℃, 35℃, and 50℃). In the study, the total energy, dissipated energy, elastic energy conversion rate, and dissipated energy conversion rate of the CGFB decreased and then increased at the same unloading rate as the curing temperature increased. CGFB peak energy characteristics and unloading rate correlate quadratically. With unloading rate, CGFB energy storage capacity rises initially and subsequently falls. CGFB unloading rate exponentially affects energy conversion rate. Damage grows slowly at the start, then nonlinearly upward concavely, and eventually sharply in CGFB with varying unloading rates. According to this research, CGFB may have three kinds of characteristics with considerable performance changes under varied temperature curing circumstances. CGFB stability control and service life assessment under high ground temperature and unloading disturbance in deep mines are based on the study findings.