Research And Application Of Numerical Optimization For Ultra-deep And Air-spaced Charge In Shuangli Mine

At present,the height of stepwise blasting in domestic metallurgical opencast mine is mostly 8-16 m due to the large angle of the ore body and high hardness of rock and so on.Based on the theoretical research and continuous tests,the blasting parameters of the spacing length,the resistance line of the chassis,the aperture,the super depth and others are finally determined.The unreasonable blasting parameters lead to not only the incomplete blasting but also the increase in mining costs.In the opencast blasting,taking the roots and large blocks as the research direction of blasting effect has attracted the attention of researchers.The existing researches on the analysis of opencast blasting effect mainly focus on the dynamic response of blasting shock wave,but there are few researches on the dynamic response of blasting multi-parameters.Because the entire blasting project requires many parameters and each one will affect the effect of the blasting,the research on the effect of stepwise blasting involves many detailed studies.In order to optimize the effect of stepwise blasting,this paper quantitatively analyzed the blasting effect from the air spacing length,super depth and mesh parameters.(1)After completing many basic researches such as modeling columnar cartridge,determining the equation parameter of JWL,etc.,which is under the condition of using conventional stepwise blasting parameters,this paper analyzed the duration of making the rock break and revealed the distributive regular pattern of the blasting stressed field in the 14-meter stepwise blasting of shuangli mine,which is under the guidance of the blasting simulated numerical data through using LS-DYNY3D and the 9 different models with the respective combinations of intermediate spacing lengths of 3,4,5m and super depth of 1,1.5 and 2m.(2)This paper not only analyzed whether the blasting load can damage the rock and the degree of the rock breakage from the perspective of rock blasting mechanism,the mutative effective stress of spacing air column and super depth,and the intensityof the whole stress field,but also studied the stressed characteristics of top step,bottom rock and rocks between adjacent blasting holes under the effect of blasting load.It's necessary to put the theoretical results into verifying by on-site industrial tests so as to achieve the purpose of guiding productive practice by comprehensively using computer analytical methods and blasting theoretical knowledge.The results of on-site industrial test in Shuangli Mine show that it is feasible.The 14 m stepwise blasting results can meet the mining requirements of flat bottom plate and unobvious roots by using the method of firstly blasting the bottom of the lower column,secondly blasting the top of the upper column and finally blasting the intermediate columns whose airspace is 4m and super depth is 1.5m.