EFFECT OF LOW GAS PRESSURE ON THE PHYSICAL PROPERTIES OF OUTBURST COAL DURING UNIAXIAL COMPRESSION

Uniaxial compression test of outburst coal was conducted to explore the mechanical characteristics of coal with outburst tendency in low gas pressure environment. The mechanical properties of coal were analyzed, the surface crack morphology of coal was obtained and the energy characteristics of coal during loading were determined. Results are as follows. In the pressure range of 0.03–1.0 MPa, the uniaxial compressive strength and elastic modulus of coal show a negative exponential relationship with pressure, and both decrease with the increase in pressure. With the increase in gas pressure, the angle between the failure surface and horizontal surface of coal body increases gradually. With the increase in gas pressure, the fracture morphology of coal failure tends to be complex. When the gas pressure is low, the coal can store a large amount of energy, and its ability to resist damage is greatly improved.