Experimental Study on Mechanical Property of Cemented Backfill in Coal Mine.

In response to the insufficiency of shear strength and severe segregation of cemented backfilling material in coal mines, a shear strength test, static segregation index test, and homogeneity degree test were carried out, taking slurry concentration (SC) as the main control factor. The effect law of SC on shear strength, the static segregation index, and the homogeneity degree was discussed. The relationship between the static segregation index and homogeneity degree and shear strength was analyzed, and the action mechanism of SC on shear strength was revealed. The research results show that for cemented backfill in coal mines, with a suspending agent content of 0 and a curing age of 28 d, when SC increases from 77% to 80%, shear strength increases by 31.43%, the static segregation index of the backfilling slurry decreases by 40.29%, and the homogeneity degree of the backfill increases by 69.23%. The increase in SC can enhance shear strength, reduce the segregation degree of backfilling slurry, and improve the homogeneity of backfill. The reason for the increase in shear strength lies in the fact that SC reduces the segregation degree of the backfilling slurry. The research in this paper has certain guiding significance for the timely support of the surrounding rock in the working face and the effective control of surface settlement.