软岩隧道洞口爆破振动研究

Research on Blasting Vibration of Soft Rock Tunnel Entrance

以同寨隧道深埋软岩隧道洞口为研究背景,进行了隧道爆破开挖振动监测试验。对振动数据进行了归一化处理,得到了关于深埋软岩隧道洞口爆破开挖的萨氏经验公式,为爆破开挖设计优化提供了参考价值。在爆破振动速度研究中,爆破振动速度最大水平径向分量大于最大垂直分量,而最大垂直分量又大于最大水平切向分量。达到洞口位置时,爆破振动速度呈现出明显的增加,坡表表面呈现出明显的振动放大效应。深埋软岩隧道洞口开挖振动规律与断面尺寸、隧道埋深和软岩节理分布等有关。基于现场试验结果,建议在对深埋软岩隧道洞口施工中,采用隧道常规监测与爆破振动监测相结合,同时增加围岩压力测试等选测项目,可以全面监控深埋软岩隧道洞口开挖爆破振动规律,不断调整和优化爆破参数,降低爆破对软岩的损伤,有效提高爆破效果和施工效率。

Taking Tong zhai tunnel with deep buried soft rock as the application case,the blasting vibration monitoring experiment of the tunnel entrance is conducted. The vibration data were normalized and the Sodev＇s empirical formula is deduced. It provides a reference value for the similar blasting design. In the blasting vibration velocity study,the maximum horizontal radial component is larger than the maximum vertical component,while the maximum vertical component is larger than the maximum horizontal tangential component. When the vibration reaches the tunnel entrance location,the blasting vibration velocity shows a significant increase,and the slope shows noticeable vibration amplification. It is found that the tunnel entrance blasting vibration is related with section size,buried depth and joint distribution,etc. Based on the test results,a combined method of routine monitoring and tunnel blasting vibration monitoring as well as the rock pressure test is recommended for the construction of deep buried soft rock tunnel entrance,These measures can fully monitor the deep buried soft rock tunnel entrance blasting vibration,adjust and optimize the blasting parameters,and reduce soft rock damage. It ensures the blasting effectiveness and considerably increases operation efficiency.