Influence of gas pressure on mechanical and seepage characteristics of coal under unloading condition
Abstract：Based on domestic-developed triaxial servo-controlled seepage equipment for thermal-hydrological-mechani- cal coupling of coal containing methane, the experimental study of unloading confining pressure of coal was performed on coal samples under different gas pressure. The results show that the characteristic of distinct dilatancy is displayed in the process of unloading confining pressure, therefore seepage channels in coal body are extended and seepage ve- locity increases. The deformation of coal containing methane per unit decreased confining pressure and seepage velocity increases with the increase in gas pressure in the same stress paths. The compressive strength decreases gradually with the increase of gas pressure. In the initial stage of unloading confining pressure, deformation modulus of coal containing methane changes little. After the yielding occurs, it decreases obviously. The deformation modulus decreases 3.71% - 7.45 % in the process of unloading confining pressure. Meanwhile, the Poisson' s ratio turns to increase and a function can be used to describe the relationship between confining pressure and Poisson' s ratio.
Keywords：gas pressureunloading confining pressurecoalmechanical characteristicsseepage characteristic
Publication Date：2012-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 1499-1504 )