Analytical Solution for Determining the Required Strength of Mine Backfill Based on its Damage Constitutive Model

Determination of backfill strength and composition are key to the use of staged open stope mining with subsequent filling. The traditional method of determining backfill strength has certain disadvantages, so it is necessary to explore a more scientific approach to obtain reasonable matches between backfill strength and excavated rock mass. Stress-strain curves of backfills with different cement-tailings ratios were obtained from laboratory mechanical tests for Zhongguan Iron Mine. Damage constitutive models prior to peak stress were established from damage mechanics. Using the principle that peak deformation energy corresponds to the energy released from an excavated rock mass, the optimum backfill strength and composition ratio were determined. The study provides a scientific basis for the backfilling design of this mine.