Numerical simulation of protection scope and stress analysis in lower protective seam mining of multiple coal seams

摘要

Taking certain coal mine No.5-2 coal seam for the study, combined with physical and mechanical parameters and geological characteristics of coal strata roof and floor of No.5121 working face protective seam, the paper uses UDEC simulation software to simulate overburden movement law of different stages in the process of lower protective seam mining of multiple coal seams as well as stress field and expansion deformation characteristics of the protected multiple coal seams, and protection scope of upper protected seams is defined in the paper.The simulation results show that: when the working face advancing to 70 m, the protected seam No.6-1 has an expansivity of 25 ‰.No.5-2 protective seam under the conditions of full exploitation, relief angles of up and down are 79°, 77° in the coal seam inclination.