Research on overlying rock damage and surface deformation prediction during coal seam mining under water bodies

Taking the coal seam mining under the river in a certain well field in Chongqing as an example, in this article, the development characteristics of overlying rock damage are analyzed and studied in coal seam mining by calculating the height of the caving zone and the height of the water conducting fracture zone of the minable coal seam. To ensure the safety of surface water bodies and production, the probability integration method is used to analyze the mining impact on the riverbed directly above the coal seam in the mining area. Calculation and expected results indicate that the vertical distance between the mining coal seam and the water barrier is much greater than the calculated vertical height of the waterproof and safe coal rock pillar, and it has little impact on the riverbed elevation and river channel. It will not change the position and trend of the river bend, and affect the vegetation growth on both sides of the river. Therefore, underwater mining is safe and feasible.