Strength Characteristics of Straw-Containing Cemented Tailings Backfill Under Different Strain Rates

Area of Science:

• Mining Engineering
• Materials Science
• Geotechnical Engineering

Background:

• Blasting in underground mines generates stress waves, a primary cause of backfill collapse.
• Enhancing backfill strength is crucial for mitigating damage and improving mine safety.
• Traditional cemented tailings backfill (CTB) faces challenges with dynamic stress resistance.

Purpose of the Study:

• To investigate the efficacy of rice straw fiber-reinforced cemented tailings backfill (RSCTB) in improving mechanical properties.
• To evaluate the impact of rice straw fibers on the unconfined compressive strength (UCS) and dynamic unconfined compressive strength (DUCS).
• To determine the optimal use of rice straw fibers for enhanced backfill performance.

Main Methods:

• Orthogonal experimental design was utilized for systematic testing.
• Unconfined compressive strength (UCS) tests were conducted to assess static strength.
• Split Hopkinson Pressure Bar (SHPB) tests were performed to evaluate dynamic strength.
• Diffusivity measurements were taken to understand flow properties.

Main Results:

• Rice straw fibers slightly decreased slurry fluidity but significantly increased UCS by over 50% compared to CTB.
• RSCTB exhibited a linear increase in DUCS with rising strain rates.
• The influence of rice straw fibers on UCS and DUCS was less pronounced than cement content and solid mass concentration.

Conclusions:

• RSCTB offers a substantial improvement in static and dynamic strength compared to conventional backfill.
• Optimizing rice straw fiber content is essential, as excessive amounts can impair long-term impact resistance.
• The findings provide valuable insights for developing stronger and more resilient mine backfill materials.