Energy and Permeability Characteristics of Gassy Coal Throughout Loading–Unloading Failing Process
摘要
The release of stress during mining operations may cause disasters. This study looked at how various testing scenarios affected the failure and permeability of gassy coal. To accomplish this, gassy coal samples were subjected to standard triaxial loading, fixed vertical unloading radial stress laboratory, and numerical simulation tests. The aim was to systematically examine how gas pressure and unloading rate affected permeability features and energy evolution throughout the failure process. The findings indicated that, as gas pressure and unloading rate increase, coal permeability rises, and the expansion point appears sooner. Moreover, there is a rise in gas pressure and unloading rate across the plastic strain of gassy coal at various failure points, as well as the value of Ue/U at the peak point. The degree of internal crack connection affects the macroscopic failure mode of coal; a larger degree of connectivity leads to a bigger failure plastic zone following failure, which in turn favors tension–shear composite failure in the coal sample.