断顶爆破在坚硬顶板条件下的冲击矿压灾害防治中应用广泛。基于动静载叠加原理，理论分析了断顶爆破防治冲击矿压的作用机制，在对冲击危险预评估和冲击危险动态演化特点分析的基础上，揭示了冲击危险具有分时、分区和分级的“三分”特征，建立了分时、分区、分级断顶爆破防治冲击矿压技术体系，应用于坚硬顶板型冲击矿压防治工程实践，并通过采取理论计算、钻屑监测和微震监测手段进行断顶爆破效果评价。结果表明：爆破后形成的裂隙区贯通为连续的弱面是控制冲击矿压最重要的区域，断顶爆破能够减弱由于顶板瞬间破断或垮落释放的动载强度，降低上覆悬顶施加在煤体内的静载强度并促使煤体峰值应力向工作面前方转移，达到降低冲击矿压危险的目的；依据揭示的冲击危险分时、分区、分级的“三分”特征，建立了“开切眼倾向断顶爆破、临空煤柱侧走向断顶爆破、工作面内超前预裂爆破和及时解危断顶爆破”的分时分区分级断顶爆破防治冲击矿压技术体系，相应进行了断顶效果评价，其中开切眼倾向断顶爆破后工作面初次来压和周期来压阶段顶板聚集的能量分别降低72%和76%；临空煤柱侧断顶爆破后煤柱内钻屑值下降0.55 kg/m；工作面内预裂爆破区域在回采期间出现微震总能量、单日最大能量均明显降低，微震频次显著增加的整体规律，验证了分时分区分级断顶爆破技术体系对防治冲击矿压的有效性。

Break-tip blasting is widely used in the prevention and control of rock burst under the condition of hard roof.Based on the mechanism of rock burst induced by static and dynamic loading,the mechanism of break-tip blasting to prevent rock burst is analyzed.Based on the analysis of the pre-assessment and dynamic evolution characteristics of the rock burst,the time-space-level division characteristics of rock burst is revealed,a technology system of time-space-level division break-tip blasting to prevent rock burst is proposed,which is applied to the engineering practice of rock burst prevention with hard roof,and it through theoretical calculation,drilling cuttings monitoring and microseismic monitoring to evaluation of break-tip blasting effect.The results show that the continuous weak surface consisted of fracture zone is the most important area to control the rock burst,the break-tip blasting can reduce the dynamic load strength released by the instantaneous breaking or collapsing of the roof,reduce the static load level imposed by suspended roof in coal,and promote the peak stress of the coal to transfer to the front of the working face,which can reduce the risk of rock burst.Based on the characteristics of "three parts" of time-space-level division of rock burst,a time-space-level division technology system for prevention and control of rock burst is established,which includes inclined break-tip blasting in cutting hole,strike break-tip blasting in coal pillar,pre-splitting blasting in working face and breaking-tip blasting in time.The system is applied to engineering practice and the effect of breaking-tip is evaluated,in which the flexural elasticity of roof decreases by 72% and 76% respectively in the initial weighting and periodic weighting after inclined break-tip blasting in cutting hole; the average amount of drilling cuttings decreases by 0.55 kg/m after strike break-tip blasting in coal pillar; the total energy and the maximum energy per day of microseisms in the presplitting blasting area of the working face are obviously reduced and the frequency of microseisms is significantly increased during the mining period.The effectiveness of time-space-level division break-tip blasting technology system to prevent rock burst is verified.