切缝药包爆生气体压力作用破岩机理研究

To date, the mechanism of detonation gas in rock blasting remains unclear. The dynamic evolution of detonation gas in slotted cartridge blasting, the impact effect of detonation gas in the near-central explosion region, and the propagation of detonation gas-driven cracks will be studied using high-speed schlieren photography, dynamic caustics and underwater explosion, assisted by the combined method of numerical simulation and theoretical derivation. The change law of physical and mechanical parameters in the propagation of detonation gas was examined, the influence of charge structure on characteristics of the dynamic flow field distribution of detonation gas will be studied, and the distribution model of pressure field and detonation gas pulsation in the near-central explosion region and the flow model of detonation in cracks will be established. Crack propagation and damage evolution will be combined to define the “damage variable” corresponding to the pressure of detonation gas, based on the theories of rock damage fracture, the damage fracture criterion for the near-central explosion region and the damage localization model at the crack tip will be established, and the dynamic damage properties and crack propagation of the rock under quasi-static pressure of detonation gas will be examined by preparing DLSM (Discrete Lattice Spring Model) program. This thesis will provide a theoretical basis for the effective utilization of explosion energy, the improvement of rock blasting technology, and the guidance on blasting engineering practice.

目前，爆破破岩中爆生气体的作用机理尚不十分清楚。采用高速纹影、动态焦散线、水下爆炸等实验方法，借助数值模拟与理论推导相结合的综合手段，对切缝药包爆生气体动态演化、爆炸近中区爆生气体的冲击效应、爆生气体驱动裂纹扩展三个关键内容进行研究。着重分析爆生气体传播过程中的物理、力学参数的变化规律，研究装药结构对爆生气体动态流场分布特征的影响规律，建立切缝药包爆炸近中区压力场与爆生气体脉动的分布模型和爆生气体在裂纹中的流动模型。将裂纹扩展和损伤演化结合起来，定义与爆生气体压力相对应的“损伤变量”，基于岩石损伤断裂理论，建立爆炸近中区的损伤断裂准则和裂纹尖端的损伤局部化模型, 通过编制DLSM（离散格子弹簧）程序对爆生气体准静态压力作用下岩石的动态损伤特性、裂纹扩展进行研究。为有效利用爆炸能量、改进岩石爆破技术、指导爆破工程实践提供理论依据。

目前，爆破破岩中爆生气体的作用机理尚不十分清楚。综合运用高速激光纹影仪、超动态应变测试、数字激光动态焦散线等试验手段，着重研究了切缝药包爆破爆生气体作用致裂机理，通过高速摄影试验多角度观测了爆轰波动的传播过程，实现了爆炸应力波与爆生气体的相对分离；通过改变装药结构，调节爆炸应力波和爆生气体的作用机制；分析了切缝药包径向不耦合装药爆破爆生裂纹动态断裂效应，对比了不同装药结构对爆生裂纹扩展的影响；开展了切缝药包轴向不耦合装药爆破水泥砂浆模型试验，揭示了爆炸应力场的空间分布规律；建立DLSM数值计算模型，研究了双炮孔切槽方式下，同时起爆，爆炸应力波和爆生气体共同作用下两炮孔间贯穿裂纹和炮孔外侧裂纹扩展的动态行为。最后将切缝药包爆生气体致裂爆破技术应用于煤矿岩巷、立井、隧道和边坡工程的爆破施工中，取得了较好的效果。研究成果可为工程实践提供试验依据和理论指导。