频繁爆破下隧道内振动传播的数值研究

为揭示频繁爆破下隧道内振动传播衰减规律,文章以蒙华铁路段家坪隧道为工程背景,利用LS-DY NA建立了三维隧道模型,模拟分析了多次爆破下隧道内近区和中远区的振动传播规律。结果表明,质点垂向峰值振速随距离和爆破次数的增大而减小,少数振速有增大的现象;近区振动衰减较快,中远区振动衰减比近区缓慢;中远区a值比近区至少小12.5%,但整体上二者的a值随爆破作用次数的增加呈缓慢上升趋势;系数K随爆破作用次数的增加而降低,近区K值降低速率普遍大于中远区,且近区K值比中远区至少大29.1%;频繁爆破下,中远区比近区较符合萨道夫斯基经验公式。

Numerical Simulation of the Propagation Law of Blast-induced Vibration in the Tunnel under Frequent Blasting

In order to reveal the law of propagation and attenuation of vibration in tunnels under frequent blasting,a 3D tunnel model is built by LS-DYNA based on the Duanjiaping tunnel on the Inner Mongolia-Jiangxi Railway,and the propagation laws of blast-induced vibration in the near area,medium and far area are simulated and ana lyzed.The results show that the vertical peak vibration velocity of the particle decreases with the increase of dis tance and blasting times except for a few exceptions;the attenuation of vibration velocity in the near area is faster than that in the medium and far areas;the value ofαin the medium and far area is at least 12.5%smaller than that in the near area,and as a whole the values ofαin this two areas increase slowly with the increase of blasting times;the coefficient K decreases with the increase of number of blasting,the reduction rate of K in the near area is general ly greater than that in the medium and far area and the value of K in the near area is at least 29.1%higher than that in the medium and far area;the parameters of the medium and far area are more consistent with the Sadovsky empiri cal formula than that in the near area under frequent blasting.