孔底设复合消能结构的岩体爆破振动特性研究

爆破振动的特性、控制方法及措施一直是工程爆破界的研究热点。基于白鹤滩水电站坝基开挖中开展的孔底设复合消能的岩体爆破开挖试验,结合动力有限元技术数值模拟,以及对实测振动傅里叶频谱分析,研究了孔底设复合消能结构的岩体爆破振动特性。数值模拟与现场监测结果表明:孔底设复合消能结构相对于常规装药结构能够大幅减小炮孔底部岩体的爆破振动速度,减小幅度达到30%以上,相应的傅里叶幅值谱峰值和主频率也有降低,可见爆破孔孔底设复合消能结构可有效降低孔底的峰值振动速度,从而控制孔底岩体的爆破损伤范围。

Study on Blasting Vibration Characteristics of Rock Mass with Composite Energy Dissipation Structure at Bottom of Blasthole

The characteristics,control methods and measures of blasting vibration have been the hotspot of engi-neering blasting.Based on the blasting test of dam foundation excavation in Baihetan hydropower station with compos-ite energy dissipation structure at the bottom of blasthole,numerical simulation analysis of dynamic finite element as well as the Fourier spectrum analysis of the measured vibration data,the blasting vibration characteristics of rock mass with composite energy dissipation structure at the bottom of the blasthole are studied.Numerical simulation and field monitoring results show that composite energy dissipation structure can greatly reduce blasting vibration of the bottom rock mass compared with conventional charge structure,and the reduction can reach more than 30%.The cor-responding peak Fourier amplitude and frequency are also reduced.It can be concluded that composite energy dissi-pation structure at the bottom of blasthole can effectively reduce the peak particle vibration velocity of bottom rock mass,thus controlling the blasting damage range of the bottom rock mass.