小净距双孔隧道爆破振动分析及爆孔优化措施

Blasting Vibration Analysis and Blast Hole Optimization for Twin-tube Tunnel with Small Clearance

为探讨小净距隧道爆破振动影响范围和程度,依托实际工程建立小净距双隧道爆破数值分析模型,对比分析不同爆破荷载计算公式下围岩位移变形以及振动速度,研究爆破荷载计算公式的合理选择,分析爆破过程中的超挖风险,提出一种简便的布孔设计方法,并依此进行数值仿真对比分析,验证该方法的有效性。对比分析表明:建立的多孔爆破数值模型能够较好地仿真隧道多孔爆破开挖振动速度的演化规律,所提出的简便多爆孔同心圆布孔方案可确定更为精确的爆破当量。研究成果可为相关的城市隧道爆破开挖需要进行振动控制的工况提供设计参考。

To study the influences of blasting vibration in excavation of a twin-tube tunnel with small clearance,a numerical analysis model for the tunnel blasting excavation is established following a practical project.The developments of wall rock deformation and vibration speed of the tunnel derived from two different blasting calculation formulas are compared mutually.The reasonable calculation equation of blasting force is selected,and the potential over-excavation during the blasting is analyzed.A simple and effective design approach of the blasting holes layout is proposed,and the numerical simulation is carried out to verify the availability of this method.The comparative analysis indicates that the numerical model of the tunnel blasting excavation can better simulate the behaviors of the vibration in the process of the tunnel blasting excavation.The research results provide a design reference for the working situations that vibration control is required in process of the blasting excavation of relevant urban tunnels.