Thickness of Horizontal Pillar for Safe Extraction Under Arching Effect of Cemented Backfill
Based on an established three-dimensional analytical model for arching stress of cemented backfill,a calculation formula for vertical load of cemented backfill was obtained.According to a model of four-sided fixed roof and a criterion for ultimate tensile strength of rock mass,a method to determine the thickness of horizontal pillar for safe extraction was obtained.The application practice of horizontal pillar extraction in 612 stope of a lead-zinc mine shows that the vertical stress of cemented backfill calculated with this analytical model is basically consistent with the numerical simulation results,and no plastic zone occurs in the roof in numerical simulation,which verifies that the reserved roof thickness determined by calculation meets the requirement of safe production.The results of stoping process show that the maximum cumulative displacement near the monitoring point is lower than the displacement limit,and the reserved roof tends to be stable.It is concluded that the determined thickness of horizontal pillar is reliable for safe extraction.
cemented backfillarching effectextraction of horizontal pillarthin plate theoryextractionsafe thickness
万方数据
维普
