Research Of Blasting Damage In Gently Inclined Layered Deposits

The blasting damage of gently inclined layered mining not only affect the safety of mining,but also increase the ore loss and dilution rate.In order to achieve safe and efficient mining,the damage range of the surrounding rock of the mining area is studied by means of blasting damage theory analysis and numerical simulation.Numerical simulations of blasting in short holes are arranged along the ore body and vertical ore body are carried out.The effective stress cloud shows the distribution of the blasting stress distribution of the pillar and roof.According to the Von Mises strength criterion,the influence of different arrangement modes on the damage range of the pillar and roof is studied.When the holes are arranged along the direction of the ore body,the damage range of the pillar is more than 5 m,the range of direct damage to the pillar is 2?3m,and the damage range of the roof is 1.00?1.50 m.When the holes are arranged vertical the direction of the ore body,the damage range of the pillar is 4?5 m,but it will not ca?se direct damage,and the damage range of the roof is 1.00?1.50 m.When the short holes are arranged vertical the direction of the ore body,the damage range of the pillar is smaller,which is favorable for the safe mining of the ore deposit.The numerical simulation of the uncoupled charge of the adjacent pillars is carried out to study the damage range of the pillar.The uncoupling coefficient(Rd)are 1.19,1.25,1.30,1.38.The time history curves of particle vibration velocity(V0)near the hole are obtained by numerical simulation,and the damage range of the pillar blasting is estimated by PPV criterion: 1.57 m,0.86 m,0.75 m and 0.65 m.When the Rd is 1.38,the damage range of the pillar is the smallest,which is 0.65 m.The study reveals that the damage range of the pillar decreases with the increase of the uncoupling coefficient(Rd).Based on the numerical simulation and theoretical analysis of the blasting,the relationship between the blasting and the rupture range of the ore is studied.And the reasonable distance(l0)between the blasting hole and the pillar is obtained.The numerical results show that the maximum effective stress value of ore rock at different burst center distance is obtained.Based on Von Mises strength criterion,when the hole uncoupling coefficient(Rd)are 1.19,1.25,1.30 and 1.38,the reasonable hole and pillar distance(l0)are 0.58 m,0.45 m,0.41 m and 0.39 m.The research provide a reference for the reasonable layout of blasting holes and the selection of parameters in gently inclined layered deposits mining.