Design Method of Protective Pillars in Pit Shafts in Residual Pillar Recovery of Industrial Square of Backfill Mining

摘要

This study used ABAQUS numerical simulation to investigate the variations?of axial stress and maximum principal strain in shafts with different sizes of protective pillars in pit shafts at various filling ratios. The simulations were performed in the?context of solid backfill mining of residual pillar of the industrial square at Baishan coal?mine. The results suggested that reasonable pillar sizes for the filling ratios of 0, 50%,?80%, and 90% were 220 m, 176 m, 154 m, and 132 m, respectively. The results were?roughly consistent with the sizes calculated using the Kowarzik theory, and proved to be?more effective in ensuring safety. When the filling ratio of the solid backfill mining was?over 80% based on a coal pillar calculation of the mine shaft with a left radius of 154 m,?the coal under the industrial square at less than that could be safely recovered with a?coal resource of 2.193 million tonnes.