Assessment of gas emission hazard associated with rockburst in coal containing methane

The stress field and gas seepage field of methane react upon each other in the process of rockburst in coal seam containing methane. Therefore, it is important to reveal the coupling mechanism between them. Due to the fact that volumetric strain describes the development of fracture, damage evolution equation for coal is built by accounting volumetric strain as an internal factor. The evolution models for porosity and permeability are built by considering the effect of shear dilation on fracture deformation. A gas -solid simulation software called TOUGH2(CH4)-FLAC is developed based on effective stress equation and permeability model which is coupled by linking two existing simulators (TOUGH2 and FLAC3D). A simulation case for gas flow in process of rockburst is carried out. The simulated result indicates that several bands of failure zone were caused by dynamic disturbance forming spall in deep coal. Methane in sorption state turns into desorption and flows out rapidly through damage-induced path that result in a rise of methane concentration in roadway shortly. The simulation results reveal the mechanism of extreme gas emission after disturbance induced by rockburst. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.