Analysis on Time-Dependent Yield Stress Behavior and Influencing Factors in Basalt Fiber-Reinforced Gangue Cemented Slurry

Due to the tendency of backfill slurry to stagnate within pipelines during transportation, a time-dependent rheological model for basalt fiber-reinforced gangue cemented slurry was developed based on the H-B rheological model and flocculation structure theory to ensure unimpeded slurry flow within pipelines over specified time periods. Experiments were conducted to investigate the time-dependent yield stress evolution of 9 mm fiber-reinforced gangue cemented slurry over time under varying conditions, specifically examining the effects of adding 9 mm fiber-reinforced (accounting for 0.5% of the total mass of the slurry) gangue cemented slurry under varying conditions. Significant effects of mass concentration, sucrose admixture content, and fly ash concentration on the yield stress of the slurry under different standing times were investigated. Research findings indicate that the yield stress of the paste increases with rising mass concentration and also rises with extended standing time. For slurries with mass concentrations ranging from 76% to 82%, the yield stress after 120 min of standing increased by 81.03%, 80%, 82%, and 97.48%, respectively, compared to freshly mixed slurries. The yield stress decreases with increasing sucrose dosage. Below 0.5% sucrose dosage, the rate of yield stress increase with standing time is relatively slow; above 0.5%, the rate increases more rapidly. After 120 min of standing, the yield stress of slurries with a sucrose dosage ranging from 0.25% to 1.00% increased by 48.66%, 54.42%, 32.90%, and 33.70%, respectively, compared to freshly mixed slurry. Yield stress decreased with increasing fly ash content and exhibited an overall steady upward trend with standing time. Based on the fitting surfaces depicting the variation in yield stress in filling materials over time under different influencing factors, fitting expressions were derived. Analysis of variance revealed that the time-dependent behavior of filling materials is primarily influenced by mass concentration, followed by retarder dosage and fly ash proportion.