Experimental Study on Permeability and Strain Characteristics of Coal Containing Gas

Based on the thermal fluid solid coupling test system of coal with gas, the permeability and volume strain of briquette samples under different gas pressures are studied. The results show that, with the increase of gas pressure, the peak strength of coal sample decreases. The stress-axial strain curve of coal sample has a good corresponding relationship with the permeability-axial strain curve. There is a permeability rebound point in the permeability-volume strain curve, and the permeability before the rebound point decreases with the increase of volume strain, and the permeability after the rebound point increases with the decrease of volume strain. The relationship between permeability and volume strain before rebound point and after rebound point can be fitted by linear expression, and the fitting degree is relatively high. The decreasing trend of permeability before rebound point is steeper than that after rebound point.