Study on Sealing Effect of a New Pressurized Grouting and Hole-sealingGas Pressure Determination Technology

In order to improve the accuracy of coal seam gas pressure measurement and solve the problems that the traditional hole-sealing pressure measurement method is liable to spray and has poor tightness, a new type of pressure measurement technology by pressurized grouting and hole sealing was proposed based on the cause analysis of failure pressure measurement. The bearing effect of the device of the pressure measurement technology by pressurized grouting and hole sealing was studied by building a mechanical equilibrium equation, and the slurry diffusion model after pressurized grouting was analyzed by COMSOL simulation. The analysis results showed that the new hole-sealing pressure measurement technology had better bearing capacity than the traditional one, which can provide guarantee for the implementation of the pressurized grouting; the slurry can reach the optimum diffusion effect when the pressurized grouting was continuously done for 12 h at the pressure of 4 MPa and the fissures around the borehole can be better sealed. The field tests testified that the new hole-sealing pressure measurement technology was more accurate and its pressure measurement time was shorter as compared to the traditional constant- pressure grouting hole-sealing technology.