Abstract:

According to the basic definition of porosity and mechanical equilibrium principle, and fully considering the primary deformation caused by the three aspects: the expansion of gas adsorption and shrinkage of desorption of coal seam , the expansion and shrinkage caused by the temperature effect, and the compression of the coal skeleton caused by the gas pressure of pore, a porosity dynamic evolution model of gas-filled coal under the compression condition (before expansion) and an effective stress equation expressed by adsorption thermodynamic parameters and gas pressure, are established According to the experimental data of porosity and triaxial stress test of gas-filled coal, the theoretical formula established above is verifed. The results show that the theoretical calculation results are consistent with the measured data and test conclusions. Fitting accuracy of theoretical model is good and the error is small. The research results have some guidance significance to the gas exploitation in coal seam and mining gas disaster prevention.

Key words: mining engineering, porosity, effective stress, temperature, gas pressure