Simulation Experiment Study On Blasting Breaking Mechanism Of Coal

On the basis of analying the structural features and mechanical properties of coal including compression strength, density, wavespeed, void ratio etc,comprehensive analyzing research findings of forefather, the coal is divided into hard coal, mid-hard coal and soft coal according to compressive strength,elastic modulus and wavespeed of coal.Cement, sand,perlite, gypsum, mica powder and vesicant are chosen to simulate coal, through testing physical and mechanical properties of simulated coal, it is found that the greatest impact on the strength of cement mortar test block is dust coal, followed by gypsum, and the minimum impact is mica powder and vesicant, however they have the greatest effect on the void ratio. The test blocks adding gypsum show clear plastic, inversely, the test blocks adding mica powder and vesicant show brittleness. Based on the integrated analysis of all kinds of simulating materials, three kinds of simulating material combinations are chosen to simulate hard coal, mid-hard coal and soft coal respectivly. According to the parameters and mix proporations of simulating hard coal, making 500mm×500mm×500mm blasting coupons and actualizing blasting after maintaining 20days, it is founded that the critical and optimum buried depth and maximum funnel volume are 300mm,75mm and 1080cm³ respectively. Finally, under the existing blasting theory, the blasting crater characteristic curve, charge embedment depth, blasting crater volume, critical and optimum buried depth of explosion crater are analyzed and the deformation energy coefficient E_b=2.62m/kg^1/3 of hard coal is obtained. This article has a reference value for the further studies on blasting mechanism of coal.