公路隧道光面爆破围岩振动衰减规律

The Attenuation Law of Vibrations in Highway Tunnel Surrounding Rocks Caused by Smooth Blasting

为了获得隧道围岩在爆破荷载作用下的振动效应,运用有限元软件ADINA建立隧道计算模型,通过加载简化的三角形等效爆破荷载,模拟了青山隧道Ⅲ类围岩段在单循环进尺为2 m、2.5 m和3 m三种情况下的爆破振动效应,得到了隧道拱顶、拱脚和边墙部位围岩的振动衰减规律。计算结果表明:围岩质点的峰值振速随着与开挖轮廓面距离的增大先急剧衰减后平缓衰减,开挖进尺越大,围岩受到的扰动越大。最后通过满足规范的安全质点振动速度来确定三种开挖进尺条件下的最大段药量大小,为类似隧道钻爆设计的合理性提供参考。

In order to obtain vibration effect of tunnel surrounding rocks under blasting load ,the tunnel calculation model was established by using the finite element software ADINA .Under simplified triangle equivalent blast loading ,the blasting vibration effect of class Ⅲ surrounding rock section of Qingshan tunnel with the single footage driving cycle being 2 m ,2 .5 m and 3 m was simulated .And then the vibration attenuation law for adjacent rocks at the arch vault ,spring and side walls of the tunnel under blasting load action was obtained .As shown by the calculation results ,the peak particle velocity showed abrupt attenuation first and then flat attenuation with the increase of excavation profile distance .The larg-er the footage ,the more vibrations the rock was subject to .Lastly ,safety particle vibration velocity in compliance with specifications was used to determine the maximum charge under these three excavation footage conditions .This study will provide reference to the rationality of blasting and drilling design of similar tunnels .