Mechanism and application of roof cutting and pressure relief in deep-hole shaped charge presplit blasting
To solve the problem of high stress and large deformation of the coal pillar and adjacent roadway caused by the suspended roof,this paper,combined with the geological conditions of the roof in the mining face,proposed a specific scheme of roof cutting and pressure relief in deep-hole shaped charge presplit blasting,and used numerical simulation and field test to conduct a comprehensive study on the effect of pressure relief.The results show that the vertical stress reduction of the coal seam roof after roof cutting is 21.62%,and the roof cutting measures can significantly reduce the stress level of the coal pillar and the surrounding rock in the adjacent roadway.The tests find that the axial penetrating cracks in the borehole are obvious,which can realize the timely collapse of the roof of the goaf.The cumulative displacement of the roof and floor is reduced by 59.27%after cutting the roof,the deformation of the two sides and the roof and floor in the roadway can be effectively controlled,and the increase of vertical stress in the coal pillar is obviously reduced.The practice has proved that the pressure relief effect of roof cutting by deep-hole shaped charge presplit blasting is remarkable,which can greatly improve the operational efficiency and provide some reference for similar mining pressure prevention and control projects.
deep-hole shaped charge blastingroof cutting and pressure reliefpresplit and cut seamsfield testmining pressure prevention and control
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