隧道掘进爆破诱发隧道后方开挖段地表振动效应分析
Analysis of surface vibration effect on tunnel excavation section induced by tunneling blasting
-
摘要: 针对目前在隧道已开挖区段地表振动效应理论研究的不足,从理论方面对隧道的地表振动效应进行了研究,并利用现场实测数据加以验证和分析。首先,对隧道掘进爆破模型进行简化,将掏槽孔的爆破简化为一系列球形药包的爆破,再利用保角映射将隧道已开挖段地表质点的振动问题转化为半空间内一系列球形药包的地表振动问题,最终得出已开挖段地表质点的振动速度计算方法。通过实际工程,对比了理论和实测的隧道轴线振速峰值分布曲线,验证了理论计算方法的可行性,同时利用理论计算方法探讨了隧道埋深对隧道轴线振速峰值的分布规律,发现隧道埋深较浅时,已开挖段振速峰值大于未开挖段的现象较明显,随着埋深的增加,该现象逐渐消失。Abstract: In view of the shortage of theories on the surface vibration effect in the excavated section of the tunnel, the surface vibration effect of the tunnel is analyzed based on theoretical and field measured data. Firstly, the blasting model for a tunnel is simplified, and the blasting of cut holes is simplified to a series of spherical charge blasting. Then the surface vibration in the excavated section of the tunnel is transformed into the surface vibration of spherical charge by conformal mapping. Finally, the method for calculating the vibration velocity of surface particles in the excavated section is obtained. Through practical projects, The feasibility of the theoretical method is verified by comparing the theoretical and measured peak velocity distribution curves. The distribution laws of the tunnel depth on the peak velocity of the tunnel axis are discussed by using the theoretical method. It is found that when the tunnel depth is shallow, the peak velocity of the excavated section larger than that of the unexcavated section is obvious. With the increase of the depth, the phenomenon gradually disappears.