Experimental Study on Grouting Seepage Characteristics in Rough Single Microfissure Under Triaxial Stress States

Area of Science:

• Geotechnical Engineering
• Materials Science
• Mining Engineering

Background:

• Deep coal mining faces challenges with high ground stress and groundwater in rock microfissures.
• Existing water-sealing technologies struggle with complex geological conditions.

Purpose of the Study:

• To investigate ultrafine cement grouting in rock microfissures.
• To analyze slurry properties and grouting simulations for optimal performance.
• To understand the impact of roughness and pressure on grout flow and fissure deformation.

Main Methods:

• Systematic analysis of ultrafine cement grout performance across various water-cement (W/C) ratios.
• Fabrication of microfissures with controlled roughness and aperture (0.2 mm).
• Triaxial stress-permeation experiments with Fiber Bragg Grating (FBG) sensors for strain monitoring.

Main Results:

• Slurry viscosity decreases and bleeding increases with higher W/C ratios; W/C = 1.6 showed unstable grout (7.8% bleeding).
• Increased fissure roughness reduces grouting success rates due to particle deposition.
• Grout flow rate decreases with roughness but increases with grouting pressure; roughness amplifies strain variations.

Conclusions:

• Water-cement ratio is key to grout performance, while surface roughness dictates grouting efficacy.
• Findings provide theoretical guidance for water-blocking grouting in microfissures.
• Optimized W/C ratios and understanding roughness effects are crucial for effective microfissure grouting in deep mines.