Study on the disaster reduction mechanism of presplitting blasting and reasonable blasting parameters for shallowly buried remnant pillars

Abstract

AbstractDisasters such as support crushing easily occur at the mining face under a shallowly buried remnant pillar; therefore, a method for presplitting blasting remnant pillars to relieve stress concentrations and reduce disaster occurrence is proposed. Based on the geological conditions of Nanliang Mine, combining theoretical analysis and numerical simulation to study the bearing characteristics and stress distribution characteristics of remnant pillars, the influence mechanism of presplitting blasting on remnant pillars in terms of the uncoupling factor, axial charge factor, blast hole arrangement, and detonation method is analyzed, revealing the presplitting blasting and disaster reduction mechanism of shallowly buried remnant pillars; furthermore, reasonable blasting parameters are determined. The results show that the rock is affected by the concentrated load within 40 m below the coal pillar; the reasonable blasting parameters are the uncoupled charge coefficient of 1.5, the axial charge factor of 1.0, and the simultaneous detonation of staggered holes. Blasting coal pillars can reduce the transmission effect of the overlying load and ensure the safe use of low‐resistance hydraulic support.