放顶煤开采爆破破碎硬顶煤研究

Study on the hard top coal crushed by blasting

以大同坚硬煤层金属网下放顶煤和全厚一次放顶煤开采试验为原型 ,采用大煤样爆破实验方法 ,按垂直层理和平行层理模拟爆破 ,研究了装药不偶合系数Ke 和线装药密度对坚硬顶煤爆破块度的影响规律 ,提出了模型与原型炸药量的换算关系式 .应用分形理论初步分析了分形块度、表面裂隙分维与爆破能量密度的关系 ;探索了爆破法破碎坚硬顶煤的合理爆破及施工参数 ,并认为垂直层理爆破Ke<1 2 ,而平行层理爆破Ke>1 2 ,有利于提高顶煤体冒放性 .

Based on the prototype of caving coal under the metal nets and caving coal on total high in hard coal of Datong,the rules of charging decoupling coefficient and explosive charge along line influencing the size of top-coal lump were researched through the virtual blasting experiment in perpendicular to coal stratification and parallel to the coal stratification. And the conversion formula of quantity of explosive between model and prototype was presented. The relations between the size of coal lump fractal, surface cranny fractal and density of blasting energy were roughly analyzed by means of the fractal geometry theory. Try to find out the rational parameters of explode and construction for blasting the hard top coal in coal mine, and gain that the possibility of the top-coal caving would be enhanced when the value of K e is smaller than 1.2 under condition of the blasting of perpendicular to coal stratification and bigger than 1.2 under condition of the blasting of parallel to coal stratification.