基于LS-DYNA的扇形中深孔逐孔起爆段别优化

Optimization of millisecond parameters for hole by hole initiation in fan-shape deep holes based on LS-DYNA

梅山铁矿是典型的"城市矿山",控制爆破振动效应对周边建筑安全意义重大。为优化其微差参数,降低爆破振动效应,利用LS-DYNA建立了准二维扇形中深孔爆破模型,在原典型微差方式的基础上,设计了五种不同段别组合的逐孔起爆方案,识别了各孔段振动速度波形,比较了各方案各孔段波形峰值。结果表明:间隔一至两个段别的微差方式更有利于应力波干涉减震;对于多孔段逐孔爆破,统一地改变孔间间隔时间往往不达到整体减震的目的;对于梅山铁矿的爆破参数,起爆段别调整为1-3-4-5-6-8-9-10-11段更有利于爆破振动效应的控制。针对模拟得出的最优方案进行了现场对比验证,现场试验表明:相对于原方案,优化后方案井下减震11.4%,地表减震15.2%,说明优化方案具有一定的应用价值。

Meishan iron mine is a typical ＂urban mine＂, it’s of great significance to control the blasting vibration effect to insure the safety of buildings surrounding. In order to optimize the millisecond parameters and reduce blasting vibration effect, quasi two-dimensional fan-shape deep holes model was built by LS-DYNA. On the basis of the current typical millisecond blasting parameters, five different millisecond patterns were designed, the vibration velocity waveform of each hole in different patterns were identified, and the peaks were also compared. Results show that： the reasonable delay time of each hole should be 25ms^50ms to reduce the blasting vibration via stress wave interference; For multi-hole millisecond blasting, vibration reduction can’t be achieved just by uniformly changing delay time of each hole; According to the blasting parameters applied in Meishan iron mine, the detonator group 1-3-4-5-6-8-9-10-11# is most appropriate to control of blasting vibration effect. Besides, field contrast test was conducted,the results show that：comparing the vibration of original pattern, vibration caused by pattern 5 is 11.4% lower for underground and 15.2% lower for surface, indicating the optimized pattern has certain application value.