A mechanistic study of coal and gas outbursts

In modeling the initiation of coal and gas outbursts, the coal seam is treated as a gas reservoir, and the mechanical responses of the seam to mining-induced changes in pore fluid pressure and effective stress fields are studied within the framework of poroelastoplasticity theory. Results are presented from numerical modeling studies, conducted using a dual porosity multi-component coalbed methane simulator which has been coupled to a coupled geomechanical-fluid flow analysis code. The model is 3-dimensional and simulates the strength and deformation properties of coal, compressibility and single- and two-phase flow properties of pore gas and water, mass transport of mixed gases in the adsorbed and free states, stress-dependent permeability, and large strain deformation. Coupled mechanical deformations and fluid flow in ubiquitous jointing and discrete joints and faults are also simulated.