Modes and mechanism for water inrushes from coal seam floor

For illustrating mechanism of water inrush from coal seam floor at different geological conditions,three modes are classified as normal strata water inrush mode,fault water inrush mode,and paleo-sinkhole water inrush mode.Water inrush mechanism at different geological conditions were analyzed.The normal strata water inrush modes are classified as the sub-mode of microcosmic progressive intrusion in thick plate by hydraulic fractured,and sub-mode of whole break in thin plate;The fault water inrush mode include sub-mode of falut direct connected,sub-mode of progressive intrusion zone of confined water influenced by fault,sub-mode of floor failure zone influenced by fault,sub-mode of progressive intrusion zone of confined water and floor failure zone influenced by fault;The paleo-sinkhole water inrush mode are divided into four sub-modes,including the sub-mode of water inrush for the thin plate theory,shear failure,thick wall cylinder and hydro-fracture.Although water inrush modes are different,two kinds of basic water inrush mechanism can be concluded as microcosmic progressive intrusion in thick plate by hydraulic fractured and whole break or failure in thin plate.