Optimization of Bunch Holes Cutting Blasting in Deep Mine Under High Stress Environment
The bunch holes,which consist of multiple dense and parallel holes and detonated simultaneously,are widely used in mines because of its high rock-breaking efficiency.With the worldwide depletion of resources in the shallow part of the earth,many mines are transitioning to the deep mining stage,and the influence of the complex high stress environment on the effect of blasting on rock breaking in the deep mining process needs to be further studied.In order to explore the law of blasting damage and fracture of bunch holes cutting blasting in deep mining under high stress stope environment,LS-DYNA finite element numerical analysis software was used to study.Combined with the mine blasting engineering practice,the planar numerical model with the same size as the actual working conditions was established,which contained four charge holes and one auxiliary empty hole.The rupture damage process of the bunch holes under no static stress was analyzed.On this basis,in the case of one-way static stress and two-way equivalent static stress,when the static stress is 20 MPa and 40 MPa respectively,the blasting fracture damage of the bunch holes cutting blasting was analyzed,and the number of failures units of the numerical model under different static stress states was compared.In addition,the hole spacing and the arrangement of peripheral auxiliary holes were optimized under different static stress conditions,and engineering experiments were carried out to verify the reliability of the optimization results by counting the chunk rate of different schemes.The results show that compared with the no static stress condition,the expansion of the bunch holes blasting damage cracks will be suppressed under the unidirectional static stress and bidirectional equivalent static stress conditions.With the increase of static stress,the number of model failure units decreases gradually,and the inhibition of crack extension is more significant.When the static stress reaches 40 MPa,no penetration crack can be formed between the four bunch holes and the center empty hole.In particular,in the bidirectional equivalent static stress state,the inter-hole crack penetration mode of the bunch holes changes from a square penetration to a circular penetration.Practice shows that according to the size of the static stress to adjust the bunch holes spacing and peripheral auxiliary holes arranged way can reduce the rate of large pieces of slot blasting,so as to obtain a good slot blasting rock-breaking effect.
blastingbunch holeshigh stresshole spacingdamageLS-DYNA softwaredeep well
NETL
NSTL
万方数据
维普
