Abstract: Through uniaxial compression mechanical tests of different gypsum types and phosphypsum composite excitation
cemented backfill,the effects of various factors on the early mechanical strength of cemented backfill and the optimal dosage
were analyzed. The microstructure characteristics and hydration mechanism of the composite filling materials were revealed
by means of SEM and EDS quantitative analysis techniques. The results show that the early mechanical strength of the cemented
backfill mixed with phosphogypsum decreases significantly,but the adverse effect of phosphogypsum decreases with the prolongation
of curing age. The significant factors affecting the early mechanical strength of phosphogypsum based cemented backfill
are phosphogypsum and glauberite. The content of NaOH is not more than 3%,the optimal content of glauberite is 1. 0%,
and the content of phosphogypsum can reach 40%. The addition of phosphogypsum inhibited the early hydration reaction
process of the composite backfill material,and the early deformation of the cemented backfill gradually increased with the increase
of phosphogypsum content,and the failure mode was mainly tensile failure parallel to the loading direction. The research
results provide reference for improving the resource utilization of phosphogypsum and help to reduce the cost of mine filling.