精确延时数（单）孔一响预裂爆破成缝（微破碎带）机理研究

Pre-splitting blasting technology has been widely used in excavation engineering including open-pit and underground. Meanwhile, the technology has achieved fruitful results. With the development of social economy, the mine production and engineering construction have gradually in-depth, high slope, weak and broken rock, the facilities need to protect in blasting zone and such a series of complex environment have turned out in pre-splitting blasting excavation engineering. At this time, the urgent demand is the quality and safety of pre-splitting blasting. This project depends on pre-splitting blast field test that several holes blasting at same time usingdigital electronic detonator precise time delay, the main blasting parameters including uncoupling coefficient, maximum single ring dose, delay time between holes, influence of guide hole to pre-splitting blasting vibration propagation law and the original rock damage degree; On the basis of model test, combined with high-speed photography observation and dynamic resistance strain gauge data acquisition system to study the cracks formation mechanism of pre-splitting blasting under control of the precise time delay. With the help of ANSYS/LS-DYNA software to simulate and calculate the three dimensional numerical model of pre-splitting blasting and study the distribution and the changing rule of stress field in rock mass under the condition of hole by hole pre-splitting blasting. Reveal the inner link of dynamic mechanical properties of rock parameters with pre-splitting blasting design and blasting practice and provide theoretical basis and guidance to safety and high quality of pre-splitting blasting under complicated environment.

预裂爆破技术已广泛用于地下与露天开挖工程，并取得了丰硕的成果，随之社会经济的发展、矿山生产和工程建设的深入，预裂爆破开挖工程呈现出：高边坡、软弱破碎岩层、爆区周边有需要保护的设施等复杂环境，此时对于预裂爆破高质量和安全性的迫切需求变得尤为突出。本项目将依托于电子数码雷管精确延时数（单）孔一响预裂爆破试验，研究主要爆破参数：装药不耦合系数、最大单响药量、孔（数孔）间延时时间、有无导向孔对预裂爆破振动传播规律、原岩损伤程度的影响规律；以模型试验为基础，结合高速摄影观测、动态电阻应变仪数据采集系统研究精确延时控制下的预裂爆破成缝机理，借助ANSYS(LS-DYNA)软件对逐孔预裂爆破三维数值计算模型的计算与模拟，研究在逐孔预裂爆破作用下岩体中应力场的分布和变化规律，揭示岩石动态力学性能参数与预裂爆破参数设计和爆破实践的内在联系，为复杂环境下预裂爆破的安全和高质量实施提供理论依据和指导。

本项目依托数码电子雷管精确延时数（单）孔一响预裂爆破试验，研究主要爆破参数装药不耦合系数、最大单响药量、孔（数孔）间延时时间、有无导向孔对预裂爆破振动传播规律、原岩损伤程度的影响规律。相关研究以模型试验为基础，结合高速摄影观测、动态电阻应变仪数据采集系统，分析了精确延时控制下的预裂爆破成缝机理，通过ANSYS/LS-DYNA软件对逐孔预裂爆破数值模型进行了计算与模拟，确定了逐孔预裂爆破作用下岩体中应力场的分布和变化规律。基于上述研究发现，精确延时预裂爆破半孔率的大小与不耦合系数呈正相关，与孔距呈负相关，且在逐孔起爆时效果最佳；预裂缝宽度与不耦合系数呈负相关，与同响孔数呈正相关；原岩损伤程度与不耦合系数呈负相关，与同响孔数呈正相关；在逐孔起爆的极限条件下，最优试验参数为不耦合系数取2、孔距取8倍炮孔直径、无导向孔，孔间延期为12ms，此时有效半孔率为85.4%，预裂缝宽度达到25.4mm，原岩损伤程度为13.5%，减振率达到29%，上述结论能为复杂环境下预裂爆破的安全和高质量实施提供理论依据和指导。