Propagation Mechanism of Coal Rock Fracture under Gas Pressure

Abstract:

The failure of coal rock under gas pressure and in-situ stress is an inevitable stage of coal and gas outburst. The propagation mechanism of coal rock fracture under gas pressure is studied in this paper using fracture mechanics. The expression of normal stress and shear stress is given first with the simplification that the fracture is elliptical. Then the relationship among critical gas pressure, fracture direction and side pressure coefficient is studied in two branches as tension-shear failure and compression-shear failure. For tension-shear fracture, the fracture will be easy to propagate while the fracture has the same direction as maximum principal stress. For compression-shear fracture, the propagation direction is determined by the difference of compression-shear parameter and friction coefficients.

• Periodical: Advanced Materials Research (Volume 402)
• Pages: 626-630
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.402.626
• Online since: November 2011
• Authors: Zhi Gang Zhao, Di Di Gan
• Keywords: Compression-Shear, Fracture, Gas Pressure, Propagation Mechanism, Tension-Shear

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