延期时间对逐孔预裂爆破振动衰减规律的影响

Effect of Delay Time on Attenuation Law of Blasting Vibration in Hole−by−hole Presplitting

为了获得逐孔预裂爆破的最优延期时间,基于Ansys/LS−Dyna有限元软件,结合现场实验研究了不同延期时间下逐孔预裂爆破的振动衰减规律,为实际工程应用提供了理论依据。结果表明:与齐发起爆相比,逐孔起爆可以有效地降低质点峰值振动速度(PPV),特别是预裂沟附近区域;随着延期时间的增大,萨道夫斯基公式的K值逐渐减小,而α值变化不大,当延期时间大于0.6T(T为单孔爆破振动持续时间)时,K与α的值趋于稳定,接近于单孔爆破;校正系数β与延期时间成反比,最优延期时间应为0.6T~1.0T;逐孔预裂成缝后对主爆区的减振率大于齐发预裂爆破。

To obtain the optimal delay time of hole−by−hole pre−splitting blasting,based on Ansys/LS−Dyna finite element software,combined with field experiments,this paper studies the vibration attenuation law of hole−by−hole pre−splitting blasting under different delay time,which provides a theoretical basis for practical engineering application.The results showed that compared with the simultaneous initiation,the hole−by−hole initiation effectively reduced the peak particle vibration velocity(PPV),especially in the area near the pre−split trench.As the delay time increased,the K value of the Sadaovsk formula gradually decreased,while theαvalue did not change much.When the delay time was greater than 0.6T(T was the duration of single−hole blasting vibration),the values of K andαtended to be stable and close to single−hole blasting.The correction coefficientβwas inversely proportional to the delay time,and the optimal delay time should be 0.6 T~1.0 T;the vibration reduction rate of the main blasting area after hole−by−hole pre−splitting was greater than that of the simultaneous pre−splitting blasting.