自由面对爆破振动信号能量分布特征的影响

Influence of free surface on energy distribution characteristics of blasting vibration

基于爆破振动实测数据,通过小波分析方法,得到不同数量自由面爆破振动信号的总能量、各频带的峰值质点振动速度(PPV)及各频带能量,进而对不同数量自由面爆破振动信号的能量分布特性进行研究。结果表明:开(掏)槽爆破,由于受单一自由面限制,大部分炸药爆炸的能量都将作为地震能量消耗掉;自由面越多,爆破振动信号总能量越少;自由面的数量可影响各频带振动分量分布,随自由面数量的增加,爆破振动能量更趋向高频分布,中低频能量有减少趋势,振动速度降低;同一振动信号中的高频带PPV虽比低频带PPV高,但振动持续时间短,能量衰减较快。建议在工程爆破的减振设计中,优化起爆方案,尽量利用多个自由面,这将比仅仅减少单段起爆药量更有效。

In combination with the measured data of the blasting vibration,the total energy,the frequency band energy,and the PPV of each band of the blasting vibration signal with different numbers of free surfaces were obtained using the wavelet analysis. Then the energy distribution characteristics of the blasting vibration signal with different numbers of free surfaces were studied. The results show that the slotted blasting or cut blasting is restricted by a single free surface,thus most of the energy of the explosion will be consumed as seismic energy; the greater the number of free surfaces,the less the total energy of the blasting vibration signal;with the increase of the of free surfaces,the distribution of the vibration components of each frequency band can be affected,which makes the blasting vibration energy more tend to be the high frequency distribution,so that the energy in the middle and low frequency can be reduced,and the vibration velocity is reduced as well;the PPV of the high frequency band is higher than that of the low frequency band,but the duration of the vibration is shorter,and the energy attenuation is faster in the same vibration signal. It is suggested that,in the design of reducing the blasting vibration,it is more effective to optimize the initiation scheme by using as many free surfaces as possible than by merely reducing the single segment of detonating charge.