| The blasting fragmentation of ore rock is the prerequisite for the formation of blasting pile.Therefore,the study of blasting damage characteristics of ore rock under different working conditions is helpful to reveal the basic principle of the formation of blasting pile.Based on the theoretical analysis and calculation of ball-charge blasting process and cylindrical charge blasting process,the blasting failure characteristics of rock under different working conditions were studied by constructing reasonable numerical model.Combined with the field construction data,the prediction model of rock mechanical properties,delay time,joint structure characteristics and other factors and the optimal rock breaking efficiency is established,which can provide reference for quantitative and standardized blasting design in engineering.The main research content of this paper is summarized as follows:(1)Based on the theory of blasting funnel formation,the blasting damage characteristics of rock with single hole spherical charge were analyzed,and the prediction model between charge uncoupling coefficient and rock blasting damage degree was established on the basis of considering the dynamic action of explosion shock wave and quasi-static action of explosion gas.The blasting damage characteristics of cylindrical rock with double holes are studied.The results show that the stress wave of simultaneous blasting with double holes has "interference effect",and the blasting damage area presents "butterfly" distribution.(2)The distribution characteristics of blasting heap in isotropic media and the migration rule of blasting block are studied,the influence rule of delay time and initiation mode on the distribution position of blasting block in ideal state is revealed,and the distribution characteristics of blasting heap in row delay initiation and hole by hole initiation are analyzed.By comparison,the simulation results are in good agreement with the actual working conditions,which can provide reference for guiding blasting construction.(3)A numerical model of jointed rock mass was established based on Voronoi structure.Combined with the field construction data,the effects of material form,rock mechanical properties and different delay time on rock mass blasting damage and explosion heap distribution were studied.The blasting damage effect of heterogeneous rock mass and the distribution characteristics of blasting pile are studied,and the relationship between the delay time and the distribution position of blasting block is analyzed.Through the numerical model of rock mass,the blasting simulation results are in good agreement with the actual working conditions,which provides a new idea for studying the formation process of rock burst heap. |
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