岩体单孔及群孔齐发爆破爆炸荷载数值分析

 采用广东岭澳核电站现场岩体的力学特性和基岩爆破参数，利用高能炸药的状态方程模拟岩石乳化炸药的爆炸过程，并假定岩石在爆炸产生的高应变率和高压环境下符合率相关的弹塑性本构关系，由此利用显式动力分析方法模拟单孔柱状装药和群孔齐发爆破柱状装药情况下的岩体爆炸应力波的传播过程，分析岩体爆炸粉碎区边界峰值应力的变化情况和衰减特征，并与相关理论公式进行比较，得到单孔和群孔齐发爆破情况下岩体爆炸荷载随装药量的变化规律。研究结果表明，爆源近区岩体爆炸冲击波压力急剧衰减；岩体爆炸峰值应力随装药量增加而增加；拉应力随药量的增长幅度远比压应力小；单孔药量的变化对岩体爆炸荷载的影响大于最大段药量的影响。工程实践中采用多爆孔小药量的爆破方式能有效减小岩体动态响应。

NUMERICAL ANALYSIS OF EXPLOSIVE LOAD OF SINGLE-HOLE BLASTING AND MULTIPLE-HOLE SIMULTANEOUS BLASTING IN ROCKMASS

Explosive load of individual blasting and multiple-hole simultaneous blasting in rockmass with column charging has been analyzed based on information of construction site at Lingdong Nuclear Power Station(LNPS)，Guangdong Province，China. The blasting progress is simulated via JWL equation of state for high explosives. And the rockmass in environment with high pressure and high strain rate induced by blasting is considered as an isotropic and kinematic hardening plasticity material including rate effects. Propagation characteristics of blast-induced stress waves have been achieved using explicit dynamic analysis code LS-DYNA. The attenuation characteristics of maximum pressure of targets in rock have been analyzed. It is reported that the numerical simulation results agree well with those from theoretical calculation. Based on maximum pressure of rock in crushed zone induced by blasting with different charging weights，the variation characteristics of blasting load with charging weight with individual blasting and multiple-hole simultaneous blasting are studied. It is noted that in region around charging holes，the maximum pressure decreases rapidly with distance from charge center. Peak compressive stress and peak tensile stress both increase with charging weight. It is also suggested that the blasting load is more sensitive to single charge weight than maximum charging weight per delay in multiple-hole blasting. For this case，it is helpful to reduce the blasting vibration when blasting with more charge holes and less charge weight.