Optimisation of anti-impact parameters and engineering practice of pre-split blasting for hard-thick disastrous rock strata
In response to the poor pre-split blasting effect of hard-thick disastrous rock strata in Binchang mining area,the key parameters of pre-split blasting are studied by data analysis,numerical simulation and engineering tests.The effects of rock tensile strength,explosive charge density,uncoup-ling coefficient and blasting hole spacing on pre-split blasting effect are simulated and analyzed,and the optimal blasting parameters for coarse-grained sandstone layer are obtained.The results show that the choice of blasting parameters during pre-split needs to be compatible with the tensile strength of the rock formation,to avoid wasting explosive energy in the fracture zone and weakening the scale of crack ex-pansion in the fracture zone.In the case of small explosive charge density,increasing the charge density obviously promotes the propagation of blasting crack,while in the case of large explosive density,the promoting effect is not obvious,which is easy to lead to the obvious increase of the range of crushing zone and waste the explosive energy.The optimal interval of the decoupling coefficient is 1.42-1.58,beyond which the crack expansion scale is small and the blasting effect is not ideal.Increasing the hole spacing reduces the tendency for inter-hole fracture penetration and makes blasting less effective,with a better hole spacing of 10 m.blasting optimisation parameters are determined for coarse sandstone,and the pressure step and support resistance of the working face are significantly reduced after the field test,with a significant reduction in the total energy and number of events of large energy microseismic events and a better pressure relief effect.The results can be used as a reference for the design of pre-split blas-ting parameters for hard-thick rock strata.
hard-thick rock stratarock burstpre-split blastingcrack extensionblast parameter op-timisation
万方数据
维普
