Grouting slurry diffusion range based on active heating fiber optics monitoring

Area of Science:

• Geotechnical Engineering
• Material Science
• Sensor Technology

Background:

• Quantifying slurry diffusion is crucial for effective grouting engineering.
• Traditional monitoring methods may lack precision in complex underground environments.
• Understanding slurry behavior impacts structural integrity and resource extraction.

Purpose of the Study:

• To propose and validate an Active Heating Optical Fiber (AHFO) monitoring method for quantifying slurry diffusion range and state.
• To investigate the relationship between slurry rheology, void ratio, and diffusion radius.
• To analyze the influence of seepage effects and water-cement ratio changes on slurry diffusion and temperature gradients.

Main Methods:

• Arranging AHFO on the coal seam floor to monitor temperature changes as an indicator of slurry diffusion.
• Deducing a theoretical calculation formula for spherical diffusion radius based on power-law fluid.
• Deriving a "water cement ratio change matrix" to account for seepage effects.
• Conducting small and large-scale three-dimensional grouting simulation tests to verify the AHFO method.

Main Results:

• AHFO demonstrated high accuracy, with relative errors between 3.00% and 14.67% in monitoring diffusion radius.
• The method successfully generated a 2D surface of grouting diffusion, revealing an asymmetric oval shape.
• AHFO showed a maximum relative error of 9.6% compared to theoretical calculations in large-scale tests.
• Observed an increase in temperature gradient with decreasing water-cement ratio, indicating a space-time effect.

Conclusions:

• AHFO is a feasible and accurate method for monitoring slurry diffusion in grouting engineering.
• The method effectively analyzes slurry diffusion and its space-time characteristics within the injected medium.
• AHFO provides valuable data for optimizing grouting operations and understanding underground material behavior.