Method of water protection based on solid backfill mining under water bearing strata and its application

In order to solve the water inrush problems induced by mining under water bearing strata,this paper propo- ses the method of water protection based on solid backfill mining. Meanwhile,the fundamental principle of this method is introduced and the evolution characteristics of water-conducting fracture in solid backfill mining are analyzed. More- over,the calculation model of critical compression ratio is established according to the predicting formula of the height of water-conducting fracture zone in solid backfill mining and the coal mining regulations and coal pillar design affect- ed by buildings,water bodies,railways and main roadway. Then,the compression ratio of coal seam induced by mining under water bearing strata is designed,which is used for the layout of solid backfill mining panel. The engineering ap- plication results in CT101 backfill mining panel show that the average measured value of mass ratio is 1. 32,which is bigger than theoretical design value and the height of water-conducting fracture zone is about 10. 0 meters,indicating that this method effectively reduces the height of water-conducting fracture zone and can achieve the goal of safe min- ing under water bearing strata.