城市浅埋隧道多临空面爆破振动强度影响因素分析

Analysis on Influence Factors of Vibration Intensity in Multi Free Face Blasting of Urban Shallow Depth Tunnel

通过现场爆破试验及振动监测,对城市浅埋隧道多临空面条件下的爆破参数对振动强度的影响作了对比分析。结果表明:首排掏槽孔至临空面的距离,对降低掏槽孔振速有重要影响;该距离较大时,临空面的降振作用将弱化。本工程首排掏槽孔至临空面的距离为2.1m时,即可显著降振。合理的雷管段位设计及炮孔布置对利用临空面降振有重要作用。

With the site blasting test and the vibration monitoring,a comparison analysis was conducted on the blasting parameters affected to the vibration intensity under the condition of the multi free faces in the urban shallow depth tunnel.The result showed that the distance between a first row of the cutting holes to the free face would have important influences to reduce the vibration rate of the cutting hole.When the distance was long,the vibration reduction of the free face would be weakened.The distance between the first row of cutting holes to the free face was 2.1 m and the vibration reduction would be obvious.A rational designed of the detonator section level and the hole layout would have an important role to the free face applied to the vibration reduction.