Study On Damage Evolution Law And Blasting Effect Of Rock Subjected To Blast Impact Loadings

With the development of social economy and the demand for industrial raw materials, mineral resources have become an indispensable material basis, and with the increasing of industrial raw materials, demand for mineral resources has increased significantly. Mining industry has made great contribution to the national economy, but now mine engineering blasting has been facing with greater pressure and challenges. The quality and effect of blasting must be improved during the production of mine blasting. Therefore, it is a great meaningful to improve and optimize the blasting effect by the theoretical and experimental research. Firstly, the nonclogging explosive test has been done through different resistance lines, and the damage law of rock has been studied under the effect of explosion shock, using ultrasonic testing and CT imaging technology. The experimental results showed that the radial damage of rock attenuation from the center of hole to around, the attenuation rate is non-linearly reduce with the distance of surrounding rock to the blasting center, the damage declined rapidly at the position within 3 times of the hole diameter from the center of hole. The axial damage of the blast hole showed a decreasing trend with the increasing of rock distance from the charge center position, the gradient greatly reduced in the beginning and gradually levelled off. There are differences between the axial and radial damage of the blast hole with different resistance line distance after the explosion.Secondly, the mechanical properties of damaged rocks were studied through uniaxial compression test of rock specimen with different damage degrees. The results showed that rock peak stress reduced with the increase of damage degree and the reduction rate gradually increased with the increase of damage degree; Stress-strain curves before peak were fitted by the polynomial. On this basis, the expression of constitutive relation of rock was proposed.Finally, blasting tests were studied with different explosion shock damage. And study the influence of rock explosive damage on blasting effect, the results showed that different resistance line distance of rock holes received different explosive impact damage, however, the rock of short resistance received the larger explosive damage with a better blasting effect.This study obtained the damage law and damage constitutive relation of rock under explosive impact, the influence of rock explosive damage on blasting effect which provided a reference for optimizing the mine blasting parameters、improving the blasting effect、enhancing the quality of blasting.The damage law, the damage constitutive relation of rock under explosive impact and the influence of rock explosive damage on blasting effect have been obtained in this study, these provide a reference for optimizing the mine blasting parameters, the improving, the blasting effect and the enhancing the quality of blasting.