Carbon dioxide blasting-based method for weakening top caving coal on hard coal seam

The invention belongs to the technical field of coal mining, in particular to a carbon dioxide blasting-based method for weakening top caving coal on a hard coal seam. The method comprises the steps of setting drill holes penetrating through a top caving coal body to a coal seam roof at an interval of 5 to 8 hydraulic supports at the roof close to the coal wall between top beams of the two hydraulic supports, placing a carbon dioxide fracturing device in the drill holes, sequentially blasting carbon dioxide according to the drill hole order, and finally, generating fractures in the hard top coal, and weakening the strength. After the hard top coal is weakened by carbon dioxide blasting, the top-coal recovery rate is improved by 20% to 30% compared with that prior roof fracturing, the fracturing effect is obvious, and the economic benefits are remarkable. 本发明属于煤矿开采技术领域，具体涉及种基于二氧化碳爆破的弱化坚硬煤层放顶煤的方法。本发明方法是在两液压支架顶梁之间靠近煤壁的顶板处，每间隔5～8个液压支架设置穿透放顶煤煤体到达煤层顶板的钻孔，将二氧化碳致裂器置于钻孔内，按照钻孔次序依次进行将二氧化碳，最终使坚硬顶煤产生裂隙，强度弱化。本发明采用二氧化碳爆破对坚硬