Coal mine roof sandstone water directional drilling water interception curtain water retention method along with mining, injection and monitoring

The invention discloses a coal mine roof sandstone water directional drilling mining-while-injection-while-monitoring water cut-off curtain water retention method, which comprises the following steps of: evaluating the influence of coal mining on roof sandstone water, roof water leakage and water level change according to a regional structure, coal mine geological conditions and hydrogeological characteristics, and judging whether a water cut-off curtain needs to be constructed or not according to a result; if so, executing the step 2; according to the method, roof sandstone directional drilling, wedge-shaped seam cutting, high-pressure fracturing grouting and real-time on-line monitoring of the water interception curtain are conducted at the same time in the coal mining process, reasonable zoning management and control over roof sandstone water are achieved, and the mining area roof sandstone water interception curtain forms a large-area roof sandstone waterproof boundary; the technical problem that in the p