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To make backfilling body meet strength requirement,physical-chemical evaluation and proportioning tests were conducted on several backfilling materials.Jigging sands,#32.5 cement and fly ash were determined as backfilling aggregate,binding material and modified material,respectively.An optimized proportion of backfilling materials with a solid mass fraction of 78%and cement:fly ash:jigging sands mass ratio of 1:2:14,was suggested to Jiangan Pyrite Mine,China.The slurry made by optimized proportion produced obvious shear thinning phenomena,and was confirmed as paste-like slurry.To analyze its rheological characteristics,L-type pipeline test and Haake VT550 rotational viscometer test were conducted.Bingham and Casson fluid models were applied to several paste-like slurry samples to simulate flow and stress states;Casson fluid model was proved to have better simulation effect on paste-like slurry with shear thinning phenomena;rheological parameters of backfilling slurry made by suggested proportion were measured.Initial yield stress,average apparent viscosity and limiting viscosity are 55.35 Pa,1.216 Pa-s and 0.48 Pa-s,respectively.Compared with Bingham fluid model,Casson fluid model has a better simulation effect on paste-like slurry with shear thinning phenomena,through calculating the residual standard deviations.
To make backfilling body meet strength requirement, physical-chemical evaluation and proportioning tests were conducted on several backfilling materials. Jigging sands, # 32.5 cement and fly ash were determined as backfilling aggregate, binding material and modified material, respectively.An optimized proportion of backfilling materials with a solid mass fraction of 78% and cement: fly ash: jigging sands mass ratio of 1: 2: 14, was suggested to Jiangan Pyrite Mine, China. The slurry made by optimized proportion produce obvious shear thinning phenomena, and was was as paste-like slurry. To analyze its rheological characteristics, L-type pipeline test and Haake VT550 rotational viscometer test were conducted. Bingham and Casson fluid models were applied to several paste-like slurry samples to simulate flow and stress states; Casson fluid model was proved to have better simulation effect on paste-like slurry with shear thinning phenomena; rheological parameters of backfilling slurry made by suggested proportion were measured.Initial yield stress, the average apparent viscosity and limiting viscosity are 55.35 Pa, 1.216 Pa-s and 0.48 Pa-s, respectively. Compared with Bingham fluid model, Casson fluid model has a better simulation effect on paste-like slurry with shear thinning phenomena, through calculating the residual standard deviations.