Study On Interaction And Rock Breaking Capacity In Underwater Explosion

Currently, the domestic and application of the land blasting is mature and perfect. Comparing to the land blasting, the research and application of the underwater blasting is lagged. Choosing double detonator as explosive charges to research the interaction of underwater explosion in this paper. In addition, based on the works of Sun Yueguang and other authors, this paper studied on the variation of blasting fragmentation under different charge conditions by utilizing the self-designed simulated water explosion pressure vessel, from which the calculation formula about charge quantity under a certain demands of block degree was obtained.By using two No.8 detonators as explosive charges, researched the interaction relationship of underwater blasting. Research shows that the shock wave was easy to superimposed nearby the perpendicular of the line connecting of the explosive charges by simultaneous initiation of two charges. Because of the existing of bubbles and their surface reflecting effect, the shock waves of the second charge generate expansion waves. Both the shock waves and the expansion waves reach nearby the charge wire successively, which induces the drop of peak value pressure and the cutoff effect. Besides, because of bubbles'in-phase amalgamation and counteract, when the delay time was 25ms, the experimental results showed the period of bubble pulse of delay charge was longer than the experimental value of single charge's and it showed some change law along with the increase of the space between two charges.While the charge explosion under the water, it takes two parts of pressure, one part is the hydraulic pressure, the other part is the outer pressure of the gas. The hydraulic pressure is related to the depth of the charge, according as the physics theory, every 10 meters depth pressure of water equal to 1 atm. Through fix the depth of the detonator cement mortar block under the water surface, change the outer gas pressure (from 0.3 MPa～0.9 MPa), one change unit as 0.2MPa) to simulate the different deep water surroundings. Utilizing the under water blasting testing system to study the charge in the block explosion under the different pressure, research the rock breaking capacity.Carried out blasting test for cement mortar block under the condition of different charge weight, and the blasting fragments are collected and statistically analyzed. By the analysis, we obtain the linear equation about the charge quantity and the big block ratio, than fitted out the calculation formula about charge quantity through 3 d projection. The derivation method for the formula in this paper has some reference significance for charge calculation in practical explosion of underwater.