Determination of the scheme and parameters of coal seam water injection in large-scale full-mechanized caving

It is emphasized on a method of raising middle water injection roadways in largescale fullmechanized caving mining coal seam during coalseam water injection, and the method has the advantages of high efficiency, multifuctions of one roadway and comprehensive effect on hazard prevention. Finite element numerical simulation method, combined with calculating examples, has been used to simulate the process of water injection in the thick coal seam and the least moisture range,being 15 times of the thickness of the coal seam,has been obtained.The dynamic relation between water injection pressure, water injection time, drill hole intervals and moisture range among technological parameters of water injection in fullmechanized caving mining coal seam has been analyzed,and a method of selecting reasonable technological parameters of water injection is given. A conclusion can be drawn that during water injection in largescale fullmechanized caving mining coal seam,considering moisture time is sufficient,and the coal may be crushed and soften, a higher water injection pressure should be adopted.In this case,the drill intervals can be expanded to 35 m.