针对某露天矿边坡爆破开挖工程对山体内邻近既有隧道的影响问题,依据有关规范及参考国内类似工程的经验,确定该隧道围岩质点振动速度控制标准为20 cm/s。对现场爆破荷载作用下隧道围岩质点振动进行了跟踪监测,提出了测点仪器安装方案,对隧道围岩质点振动衰减规律进行了分析,水平径向、水平切向和竖直向峰值振速衰减规律拟合系数均在0.85及以上,并及时反馈信息,优化爆破参数。结合数值分析,得到了隧道围岩振动速度与动应力分布规律,计算得到围岩质点振动峰值速度为19 cm/s,验证了预估药量的可靠性,为工程的顺利进行提供了安全保障。
In view of the effect of slope blasting and excavation in an open pit mine on the existing tunnel, the particle vibration velocity control standard of the surrounding rock is determined at 20 cm/s, with reference of the relevant standards and similar domestic engineering experience. The particle vibration of tunnel wall under the blast loading is monitored, and an installation scheme for measurement instrument is put forward. And the attenuation law of particle vibration at tunnel surrounding rocks is analyzed. The fitting coefficients of the vibration velocity attenuation at horizontal radial, horizontal tangential and vertical peak are 0.85 or above. Information feedback in time can contribute to optimizing the blasting parameters. Combined with numerical analysis, the vibration velocity of tunnel surrounding rock and the dynamic stress distribution rule are obtained. The peak value of particle vibration velocity at surrounding rock is 19 cm/s, which verifies the reliability of the estimated explosive quantity. The research provides security for the smooth construction.