地铁隧道掘进爆破地表震动效应研究

Study on Vibration Effects of Ground Induced by Metro Tunnel Excavation Blasting

以武汉地铁二号线隧道工程为背景,对爆破振动强度进行实时监测,并结合数值模拟软件计算,研究掌子面前后方地表振动特性及变化规律。结果表明:用萨道夫斯基公式对隧道掘进前方地表振速进行拟合时,相关性较好,而隧道掘进后方地表振速拟合的相关性较差。数值计算所获得的地表峰值振速变化规律及特征与现场实测结果基本一致,成形隧道对岩体整体结构的改变导致地表振速产生放大效应,使得掌子面后方已开挖区地表振速比掌子面前方相应点的振速大,因此,在确定隧道掘进爆破施工方案时,必须考虑到隧道地表振速的这种放大效应,否则很可能危及掌子面后方地表建筑物的安全。

Taking the project of Wuhan metro 2nd Line as the background, the blasting vibration intensity was realtime monitored and combined with the calculation of numerical simulation software. The studies are carried out on the characteristics of surface vibration and attenuation law in front and back of the tunnel face. The results demonstrate that there is a good correlation when the surface vibrating velocity along the tunneling direction is fitted by Sadaovsk formular, whereas the fitting correlation is poor in the opposite direction, the characteristics and attenuation law of surface peak partical velocity in numerical simulation agree well with that in the spot experimental monitoring. There is amplification effect of vibration velocity as the rock structure has been changed due to digged tunnel, so the surface vibrating velocity in back of the tunnel face which has been excavated is larger than that in front, therefore, the amplification effect of surface vibrating velocity in the tunnel must be taken into account when the choice of blasting scheme will be determined, otherwise it is likely to endanger the safety of ground surface buildings which is in back of the tunnel face.