Coal mine old goaf water inrush monitoring and judging method

The invention discloses a coal mine old goaf water inrush monitoring and judging method, and relates to the field of coal mine old goaf water disaster monitoring. Due to the influence of mining, a plastic failure area, namely a top plate water flowing fissure zone and a bottom plate failure zone (the depth is marked as h1) is developed in a certain range of a top plate and a bottom plate of the old goaf; when a finished rock stratum (an effective water-resisting layer, the thickness of which is recorded as h) between a roof water-guiding fissure zone (the height is recorded as h2) generated during mining of a coal seam below an old goaf and a bottom plate failure zone of an overlying old goaf is thin, under the action of an overlying rock mass and the water pressure of the old goaf, the effective water-resisting layer possibly generates plastic failure, a water-guiding channel is formed, and the water-guiding fissure zone is prevented from falling off. Therefore, accumulated water in the top old goaf enters t