Coal mine water inrush danger early warning method and rock mass single fracture development range calculation method

The invention relates to the field of coal mine safety monitoring, in particular to a coal mine water inrush danger early warning method and a rock mass single fracture development range calculation method which can quantitatively analyze the damage degree of a waterproof rock stratum and are high in accuracy. The method comprises the following steps: firstly, arranging a vibration signal acquisition device, and dividing a water-resisting rock stratum into a plurality of water insulation sub-layers; secondly, calculating the development range of a single fracture of a rock mass; thirdly, dividing all micro-seismic events to each water insulation sub-layer at an interval of time T; fourthly, performing energy nuclear density calculation on the development range of the single fracture of therock mass of the micro-seismic events; fifthly, comparing the Wi and Wi of each grid of each water insulation sub-layer; sixthly, superposing the comparison results in the vertical direction toobtain a ratio N of the number