1. School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing　 100083,China;2. State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology ( Beijing),Beijing 　 100083,China;3. Beijing Tiandi Huatai Mining Management Co. ,Ltd. ,China Coal Technology & Engineering Group Corp. ,Beijing　 100013,China

纳林庙二号井621-02工作面实施"等深炮孔"预裂爆破后,顶板垮落效果不理想,初次来压时产生巨大冲击波,工作面片帮严重,30~90号支架安全阀开启。针对此,对浅埋大采高工作面顶板预裂爆破机理进行断裂力学分析,提出了"阶梯炮孔"预裂爆破新方案,理论计算出爆破后基本顶初次断裂步距和合理炮孔间距,并利用有限元非线性动力学软件LS-DYNA对两种爆破方案进行数值模拟,对比分析爆破岩体的Mises应力演化规律,得知"阶梯炮孔"爆破效果更好。现场实践表明,621-03工作面采取"阶梯炮孔"爆破后,初次来压步距约为60 m,支架压力约为38.5MPa,比621-02工作面的初次来压步距(70 m)和来压强度(42.0 MPa)均显著减小,且未出现切顶、飓风等现象,实现了浅埋大采高工作面安全高效开采。

While the “equal deep holes” blasting scheme was carried out at the 621-02 mining face of Nalinmiao No. 2 coalmine,China,the blasting effect was not ideal for the occurrence of a huge shockwave,a heavy rib fall and the safety valve opening of No. 30-90 supports during the main roof initial fracturing. Aimed at solving the problems,the authors analyzed the blasting mechanism of shallow depth mining face with a large cutting height,put forward a new blasting scheme that the blasting holes are ladder-like distributed,calculated the main roof initial fracturing distance after blasting and the rational blasting hole spacing. Furthermore,the authors comparatively analyzed the Mises stress evolution of two blasting schemes using the numerical simulation of nonlinear dynamic finite element software LS-DY- NA,and found that the new blasting scheme’ s effect is better. Field test results show that while the new blasting scheme was carried out at the 621 -03 mining face,its roof initial pressurized distance and weighting intensity were 60 m and 38. 5 MPa,while the 621-02 mining face’s were 70 m and 42. 0 MPa. In short,the new blasting scheme significantly reduced the roof initial pressurized distance and weighting intensity. At the same time,no roof cutting and shockwave accidents occurred and a safe-efficient mining was achieved at the 621-03 mining face.

国家自然科学基金资助项目(51374215,51622404)；北京市科委重大科技成果转化落地培育项目联合资助项目(Z151100002815004)；霍英东教育基金会第十四届高等院校青年教师基金应用课题资助项目(142018)；

Zuo Jianping,Sun Yunjiang,Liu Wengang,et al. Mechanical analysis and blasting mechanism of main roof initial fracturing in shallow depth mining face with large cutting height[ J]. Journal of China Coal Society,2016,41 (9):2165 - 2172.