Experimental Study On Explosive Stress Wave And Blasting Effect In Coal Mass

At present the academic research of coal was still at the start stage.Most of research was illustrated the construction technology and the effect after blasting which lacked researching the blasting mechanism of coal.These reason had hindered the explosive applied to coal.This article carried on research for blasting mechanism of coal.Firstly,on the basis of consulting data and considering fully application of coal in practice,we divided the coal into three classes as hard coal,mid-hard coal,soft coal.Then,according to the similarity theory determined the similar material and blending ratio. Finally,through exploding the models of coal which made according to the blending ratio carried on analog experiment of explosive stress wave and blasting effect in the coal.Through the experimental study received these conclusion.The attenuation index of explosive stress wave of coal was greater than normal rock on the internal action of blasting;the critical depth of coal and the coefficient of deformation energy of coal were bigger than general rock on blasting crater;the optimum depth of coal was greater than rocks'which obtained from curve of crater characteristic;the injury value of coal was calculated by the expression of rock injury which expressed by velocity of sound,the result showed the injury of coal was larger than rocks'and the gas which produced from explosive obviously damaged the coal;the statistical result of fragment distribution indicated the coal occupied more proportion than rock at small fragment and the rock occupied more proportion than coal at large fragment;through measuring the modal's total length of crack gained the crack of coal was more length than rocks'after blasting.