Synergistic deformation in a combination of cemented paste backfill and rocks: Fid-Bau Portal

Synergistic deformation in a combination of cemented paste backfill and rocks

Zhao, Kang / Huang, Ming / Zhou, Yun / Yan, Yajing / Wan, Wenliang / Ning, Fujin / He, Zhiwei / Wang, Junqiang

Highlights • The synergistic deformation mechanism of the backfill-rock combination assemblage was studied. • The damage pattern and mechanism of the backfill-rock combination assemblage were analyzed. • The acoustic emission characteristics of backfill-rock combination assemblies are discussed and compared. • The acoustic emission characteristics of the assemblies reflect the synergistic nature of the damage to the specimens.

Abstract In this study, cemented paste backfill (CPB) specimens comprising tantalum–niobium ore tailings and rocks, with various cement–tailings (C/T) ratios of 1:4, 1:8, and 1:10, were evaluated to elucidate the mechanism of synergistic deformation via uniaxial compression tests. The results indicate that the overall strength of the composite body is similar to that of the single CPB specimen. The elastic modulus of the composite body increases as the strength ratio of the two specimens decreases. The strength of the two specimens in the composite body the larger the ratio, the larger the Poisson's ratio of the backfill specimen, but the smaller the Poisson's ratio of the rock specimen. The stress–strain curve of the composite body is similar to that for the single CPB specimen; it can be divided into four stages. This curve indicates that the failure mode primarily manifests as shear and tensile failures in the CPB specimen. For the composite body, the strain of the backfill is significantly larger than that of the rock. However, the deformation in these two materials exhibits good synergy; only limited hysteresis is observed in the change time. During the loading process, the assembly exhibits different acoustic emission (AE) activities for the four stages. The AE ringing count produced by the CPB is significantly higher than that of the corresponding rock when the intensity ratio of the two specimens in the assembly increases. This trend becomes more obvious with an increase in the strength ratio of the two specimens in the composite body. The peak stress of the combined body lags behind the peak of the ringing counts, and the AE characteristics of the combined body reflect the synergy of the failure of the two specimens. The results of the study can provide a reliable theoretical basis and technical reference for the design of structural parameters of infill mining.