Experimental Study on Strength and Deformation Characteristics of Gangue Cemented Backfill Under Optimal Grading Conditions

Based on the talbol’s theory, the best gradation of filled gangue is obtained, and cement with different mass ratios was added. The uniaxial compression test of gangue cemented backfill is carried out under different curing age conditions, and its strength and deformation characteristics and the final failure mode are studied. The results show that the gradation of talbol coefficient n=0.4 is the best gradation of gangue with particle size no more than 40 mm; the more the cement content, the longer the curing age, and the greater the compressive strength of the specimen; the whole process of uniaxial compression stress and strain of gangue cemented backfill is divided into four stages, namely, pore fracture compaction stage, elastic deformation stage, fracture expansion stage and post-peak failure stage; the gangue cemented backfill exhibits different degree of strain softening characteristics after reaching the peak strength. The final failure modes are mainly three types, namely, splitting failure, shear failure and conical failure. Splitting failure is the most important failure mode.