School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing)National Key Lab of Coal Resource and Safety Mining,China University of Mining and Technology (Beijing)

针对纳林庙二号井621-02浅埋工作面采用"直线"炮孔预裂爆破后,在基本顶初次断裂时产生强烈的矿压显现现象,基于对顶板预裂爆破机理和炮孔布置的分形几何理论分析,给出了不同炮孔布置方式的分形维数表达式,计算出"三角形"布置炮孔的分形维数为1.15,显著大于"直线"布置炮孔的分形维数1.0。据此提出了"三角形"布置炮孔预裂爆破的改进方案,利用有限元非线性动力学软件LS-DYNA对2种爆破方案的Mises应力演化规律进行数值模拟分析,结果表明:改进方案反射应力波的做功效果更好,应力波的衰减更慢,有利于爆炸产生的能量更充分地去破碎岩石。

Accoding to a pre-stilting blasting of the straght line boreholes aplid to No.621-02 shallow depth coal mining face in Nalinmia No. 2 Mine,when aprimary breaking ofthe basic of ocured a serious mine pressure behavior phenomenon would ocur.Based on the analysis of the pre- s litig blasting mechanismof the roof and the fractal geomery thaory of the blasting borehole layut.the fractal dimension expression of the different blasting borehole layout mode was providedThe fractal dimension of the deia layout blasting boreholes was calculated as 1.15 and was obviously igher than the fractal dimensionof thestraght line layout blastng boreholes as1.0.Therefore,the pre- pliting blasting iproved plan with the deta layout blasting boreholes was provided.The fnte element nonlinea dynamics software LS- DYNA was applied to the numercal sinulation analysis on the Mises stress evoludion aw ofthe two blasting plans.The resuts showed that the wrk efifc ofthe reflecion stress wave for the improved plan woult be better and the attenuation of the stress wave would be more slovw and favorable to the blasting energy tofulybreak the rocks.

国家自然科学基金资助项目(51374215,11572343)；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)；高等学校学科创新引智(111计划)资助项目(B14006)；北京市科委重大科技成果转化落地培育资助项目(Z151100002815004)；