Abstract: Gradualness failure formation process of water inrush channel is the key problem for study on water inrush mechanism of mining, sustained coupling effect of seepage damage induced by double effect of groundwater and mining disturbance finally leads to the formation of rupture channel. Calculation program considering the double failure criterion of tension shear and compression shear for rock mass under the groundwater effect, in order to get the catastrophe evolution process of crack initiation, propagation, transfixion and channel formation for surrounding rock of water insulation under mining influence, coupling effect of stress and seepage damage for the catastrophe evolution process has been analyzed, and the formation trajectory of water inrush channel has been accurately located. Based on the calculation results of numerical experiment, water inrush channel finally forms due to strength decreased of rock mass induced by the sustained coupling effect of stress and seepage damage, and surrounding rock of water insulation experiences group crack initiation, propagation and transfixion, when the water inrush channel of group cracks suddenly connects to each other, rupture damage energy of rock mass increases sharply, shearing stress of rock mass near the channel suddenly drops, permeability coefficient and discharge increase sharply, precursor information of water inrush has been pregnant with the different physical field of rock mass at the channel path.

Key words: coal mine, water inrush channel, gradualness failure process, multi-field coupling mechanism, damage energy, simulation analysis