Research And Application Of Millisecond Blasting Between Holes Under The Condition High Bench Air Separation

In order to meet the requirements of mine blasting effect,bench deep hole blasting is an important production link of open-pit mine.The research on dynamic response of blasting parameters in open-pit mine under the action of blast shock wave has attracted the attention of scholars.However,the millisecond blasting between holes is an important initiation mode of deep hole blasting.Due to the difference of mine blasting conditions and environment,different blasting effects are produced.Although most data have different emphases,they are all expounding the theme in this respect.For the condition of high bench air interval,the millisecond blasting between holes is a difficult problem in open-pit mine blasting,and with the increase of open-pit mining depth,the problem of determining reasonable hole to hole parameters becomes more and more difficult.In order to explore the best detonation delay time for the short-distance blasting between holes under the condition of high-step air separation,this paper uses the open-pit high-step blasting of Barun Mine as the research model,and the high-step air separation positions are located at 11 m,12m,13 m,and 14 m respectively.The delay time between holes is 9ms,10 ms,and 12 ms for different combinations of detonation scheme models.With the help of large-scale dynamic nonlinear finite element software,from the perspective of improving the rock breaking mechanism,the one-dimensional unsteady flow stress wave theory and explosive gas The pressure quasi-static comprehensive action mode is used as the research carrier,combined with the air gap theory and the damage mechanics theory,the semi-empirical formula of the time delay control proposed by Hanukayev is revised,and the same row of phases under the condition of the high step middle axial air gap is discussed.The stress field distribution of the detonation between adjacent holes at different time difference,and the respective characteristics of the stress field in the middle of the blast hole when two holes are detonated at the same time are further compared.The results show that for the short-difference blasting between holes under the condition of a high-step air interval of 5 m,different short-difference times between holes have an important influence on the stress field distribution in the middle of the blast hole.The short-difference time is short and the average effective stress peak value between the holes The average value of is 26.4 MPa,the average effective stress duration is 18.16 ms,and the differential time is too long,the average value of the average effective stress peak value is 26.9 MPa,and the average effective stress duration is 18.54 ms.Finally,the differential interval time of 12 ms is reasonable.The average value of stress in the rock mass in the middle part of the blast hole is higher and the duration is longer,which is also more beneficial to broken rock.Finally,the characteristics of the respective stress fields of simultaneous initiation between holes and millisecond initiation between holes are compared,which provides a theoretical basis for related engineering applications,achieves the combination of computer and theory,and confirms the purpose of field tests.