Experimental study on grouting diffusion and reinforcement law of grouting backfilling mining in caving zone

Area of Science:

• Geotechnical Engineering
• Materials Science

Background:

• Grouting in caving zones presents challenges in visualizing filling space, slurry flow, and the bearing capacity of gangue-slurry mixtures.
• Understanding these parameters is crucial for effective ground support and stability in underground mining and civil engineering applications.

Purpose of the Study:

• To investigate the flow characteristics of fly ash slurry.
• To evaluate the confined compression and creep behavior of gangue-slurry mixtures under varying gangue particle gradations.
• To establish methods for assessing filling space and the mechanical properties of grouted materials.

Main Methods:

• Experimental investigation of fly ash slurry flow.
• Confined compression tests on gangue and gangue-slurry mixtures with varied particle size distributions.
• Creep tests to assess long-term deformation and stability.

Main Results:

• Calculated and measured porosities demonstrated similarity, offering a method for filling space assessment. Slurry injection volume correlated with gangue porosity, though high concentrations or dense packing risked infiltration.
• Stress-strain curves for both gangue and the mixture exhibited an exponential relationship, with porosity and larger particle content influencing maximum strain.
• Distinct temporal patterns in internal energy changes, particularly medium-term fluctuations, indicated significant internal structural adjustments.
• Creep tests revealed gradual axial strain, suggesting enhanced stability and bearing capacity of the mixture.

Conclusions:

• The study provides a foundational understanding of fly ash slurry grouting in caving zones.
• The findings offer practical insights into managing slurry flow, assessing filling space, and predicting the mechanical behavior of grouted materials.
• The developed methods and observed properties contribute to optimizing grouting strategies for improved ground support and stability.