Abstract: Based on the mechanisms of micro-crack growth, a micro-crack damage tensor has been introduced to the classical Biot’s poroelasticity theory to deduce the relation between the microscopic damage evolution of rock and the macroscopic mechanical and hydraulic properties and to establish the hydro-mechanical coupling model and governing equation based on the fracturing evolution. Then the proposed model has been programmed with MATLAB and COMSOL to simulate the failure process and flow evolution of rock under hydro-mechanical couplings. On this basis, numerical simulations of coal mining above a confined aquifer have been performed and the mining-induced fracturing, failure patterns and flow evolution in coal seam floor have been analyzed systematically. The numerical results clearly show how the groundwater inrush channel is formed.

Key words: micro-crack damage, seepage, fracturing evolution, groundwater inrush