Strength, acoustic, and fractal behavior of fiber reinforced cemented tailings backfill subjected to triaxial compression loads

Abstract

Overall, solid materials like CTB (i.e., cemented tailings backfill) give out low-level seismic signals as they are under stress in underground mining applications involving ground control, rock burst, and coal bump monitoring. To offer a means of establishing zones of instability, the acoustic emission (AE) technique uses these seismic signals to study the fracture/failure behavior of CTB materials. This paper develops a highly efficient AE technique to explore the influence of type, length and dosage of fiber over strength, acoustic and fractal characteristics of CTB materials. The uniaxial compression test of fiber reinforced CTB (FRCTB) was carried out with the help of an electronic universal testing press while the triaxial compression failure process of FRCTB was recorded via the AE monitoring system. The research findings prove that polypropylene provides the best fiber reinforcement influence, offering an optimal fiber dosage and length of 0.6% and 12 mm, respectively. FRCTB's peak strength in triaxial compression surges when confining pressure is boosted. However, non-reinforced CTB offers better confining pressure effect better than FRCTB. Besides, the ring count-time and energy-time during the triaxial compression of CTB are mainly manifested in four stages: compacting, calm, and intensive and active stages, and the fractal theory is applied to FRCTB's fracture properties. In conclusion, this work presents a practical advice regarding the field durability monitoring/reinforcement of CTB used for ground support and a secured work platform providing access for mining workers/equipment.