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Mechanical response of stress damaged cemented tailings backfill based on pore structure and acoustic emission characteristics
Highlights The mechanical response of stress-damaged CTB (SDCTB) was investigated. The effect of stress damage level on the mesoscopic structure of SDCTB was determined. The rupture process of SDCTB was probed based on AE signaling and fractal theory. Compaction enhancement and cracking damage together determine SDCTB performance.
Abstract The mechanical response of cemented tailings backfill (CTB) is essential for its achievement of underground mine ground pressure management and productivity improvement. However, long-term, continuous, high-intensity mining causes CTB subject to mining stress disturbance, which inevitably affects its mechanical properties and stability when serving as a load-bearing structure. Therefore, the stress-damaged CTBs (SDCTB) were prepared to take 20%, 40%, 60%, and 80% uniaxial compressive strength (UCS) as the stress-disturbed levels (SDL) in this study. The effects of SDLs and curing ages (3, 7, 14, and 28d) on the mechanical properties and damage characteristics of STCTB were also investigated. The results showed that as SDL enhanced, the UCS and elastic modulus of the backfill (except SDCTB with 60%–80% SDL) increased and then decreased, and 20% SDL was the turning point. Meanwhile, the external load disturbance significantly affected the initial compaction stage of the stress–strain curve of the backfill. Proper SDL reduced the porosity of SDCTB and induced the transformation of macropores to mesopores and micropore. In addition, the AE signals of CTB and SDCTB with 20% SDL showed an active-calm-active stage during compression. The AE signals of SDCTB with 40%–80% SDL remained active stage. The higher SDL aggravated the crack sprouting and expansion rate of the backfill. Also, the correlation dimension (D) of AE ringing counts and amplitudes fully reflected the rupture characteristics of the backfill. The failure mode of SDCTB changed from mixed tensile-shear to tensile failure as the curing age increased. Comprehensive macro-mesoscopic experimental outcomes, the effect of compaction enhancement and cracking damage of the backfill under the external load were proposed, and the two were competing. The results of this study provide a theoretical basis for the stability assessment of the backfill under mining stress disturbance.
Mechanical response of stress damaged cemented tailings backfill based on pore structure and acoustic emission characteristics
Highlights The mechanical response of stress-damaged CTB (SDCTB) was investigated. The effect of stress damage level on the mesoscopic structure of SDCTB was determined. The rupture process of SDCTB was probed based on AE signaling and fractal theory. Compaction enhancement and cracking damage together determine SDCTB performance.
Abstract The mechanical response of cemented tailings backfill (CTB) is essential for its achievement of underground mine ground pressure management and productivity improvement. However, long-term, continuous, high-intensity mining causes CTB subject to mining stress disturbance, which inevitably affects its mechanical properties and stability when serving as a load-bearing structure. Therefore, the stress-damaged CTBs (SDCTB) were prepared to take 20%, 40%, 60%, and 80% uniaxial compressive strength (UCS) as the stress-disturbed levels (SDL) in this study. The effects of SDLs and curing ages (3, 7, 14, and 28d) on the mechanical properties and damage characteristics of STCTB were also investigated. The results showed that as SDL enhanced, the UCS and elastic modulus of the backfill (except SDCTB with 60%–80% SDL) increased and then decreased, and 20% SDL was the turning point. Meanwhile, the external load disturbance significantly affected the initial compaction stage of the stress–strain curve of the backfill. Proper SDL reduced the porosity of SDCTB and induced the transformation of macropores to mesopores and micropore. In addition, the AE signals of CTB and SDCTB with 20% SDL showed an active-calm-active stage during compression. The AE signals of SDCTB with 40%–80% SDL remained active stage. The higher SDL aggravated the crack sprouting and expansion rate of the backfill. Also, the correlation dimension (D) of AE ringing counts and amplitudes fully reflected the rupture characteristics of the backfill. The failure mode of SDCTB changed from mixed tensile-shear to tensile failure as the curing age increased. Comprehensive macro-mesoscopic experimental outcomes, the effect of compaction enhancement and cracking damage of the backfill under the external load were proposed, and the two were competing. The results of this study provide a theoretical basis for the stability assessment of the backfill under mining stress disturbance.
Mechanical response of stress damaged cemented tailings backfill based on pore structure and acoustic emission characteristics
Song, Xuepeng (author) / Hao, Yuxin (author)
2023-09-06
Article (Journal)
Electronic Resource
English