The Study Of Detonation Performance Of Detonation Cord Under Condition Of Decouple Charge

The detonating cord initiation technology has been widely used in blasting. Decoupling charge condition has a significant impact on the initiation performance of the detonating cord.This paper analyzes the initiation performance of the detonating cord under many different decoupling charge conditions.lt is carried out by four specific researches--detonation theory analysis, numerical simulation, blasting experiment verification and engineering practical application. Through the mutual authentication and improvement of the four parts,we obtained the physical essence of the detonating cord initiation under decoupling charge conditions, derived and fitted the attenuation formula of the air shock wave peak overpressure and its action time within the blast hole. On this basis,we combined the attenuation formula and the results of the blasting experiments, concluded the factors which impact the performance of detonating cord initiation. The main contents and results obtained are as follows.(1) According to detonation physics, the physical model of initiation technology within the detonating cord hole was established.This model assumed that the detonating cord closed to the inner wall of the blast hole, there were only detonating cord and air in the blast hole, and the blast hole wall was unbroken and rigid. Using the shock wave theory,we tried to infer the propagation process of air shock wave which generated during the explosion within the blast hole. Based on the explosion similar rate and the dimensional analysis theory, the emprical formula of the air shock wave peak overpressure and its action time were derived.(2)Using ANSYS/LS-DYNA3D to conduct the numerical simulation of the detonating cord initiation technology, we found the law of air shock wave propagation within the blast hole and fitted the parameters of return shock overpressure emprical formula.(3) In order to test the effect of air decoupling condition on the performance of detonating cord initiation, the blasting experiments were conducted. The results showed that under the conditions that air gap is 25mm and decoupling coefficient is 2.0, the detonating cord can detonate the emulsion explosives successfully.Comparing the fitting formula to the results of blasting experiments,we found that the value of fitting formula was smaller than the value of blasting experiments.It indicates that the cartridges of emulsion explosives have effect on the propagation of air shock wave within the blast hole.(4) Throngh theoretical analysis and numerical simulation of blast wave propagation in some dielectric material, it shows that the properties of the dielectric material have significant effects on the propagation of shock wave.