浅埋隧洞钻爆技术与振动控制

复杂环境下的浅埋隧洞钻爆开挖，爆破振动的控制可分别考虑建筑物振动安全允许值和住民可接受振感的振速值。根据隧洞钻爆部位与周围建筑物的空间关系的变化，基于振速控制要求的不同，划定不同的控制洞段。隧洞出口明挖段采用小孔距的浅孔台阶爆破；在需特别控制的洞段，将循环进尺减少至0.8 m，断面开挖方式调整为分四次开挖，有效改善了爆破临空面条件和减弱孔底挟制作用；在振动控制要求降低的洞段，逐渐将循环进尺变为1.2 m 和1.5 m，断面改为分两次开挖或一次性开挖。每次爆破的其它孔网参数和药量计算基于上一次爆破振速监测数据的反馈作适当调整。在此方案下，振动控制效果达到了工程要求。

Drilling and Blasting Technology and Vibration Control in Shallow Tunnel

In the drilling and blasting of shallow tunnel under complex environment,the allowable safety value of structural vibration and the acceptable vibration velocity by residents could be considered respectively to control the blasting vibration. According to the change of spatial relationships between positions of the tunnel blasting and sur-rounding buildings,different controlling tunnel parts were delimited based on different control requirements of vibra-tion velocity. The short-hole bench blasting with small hole distance was adopted in the tunnel exports. In special controlled tunnel part,the cycle footage decreased to 0. 8m,and the section excavation method was adjusted to four-time excavation,which effectively improved the condition of free faces and reduced the hole-bottom squeezing effect. In tunnel parts of lower vibration control requirements,the cycle length could be 1. 2m or 1. 5m,and sections were excavated once or twice. The hole parameters and charge amount in every blasting section were adjusted based on the feedback of the monitoring data. The controlling of vibration effects fitted the engineering requirements well.