下穿既有隧道爆破振动响应研究

以沪昆客专贵州段小高山隧道泄水洞下穿既有高铁隧道正洞爆破施工为工程实例,在泄水洞开挖下穿既有铁路隧道时,为确保既有隧道结构安全和爆破振动影响问题,采用稳健回归和小波包等分析技术,研究了在既有隧道正洞内设置沙质缓冲层,其在下穿隧道施工中爆破地震波特征和传播机制。结果表明:主频率分布范围较广;缓冲层有效地吸收了大部分高频带能量,到达既有隧道结构的能量主要集中在第2~第4频带部分,振动速度峰值降低了34%左右,各方向的主振频率主要位于5~70 Hz的中低频范围;切向的能量占主要优势,须重点关注。研究为下穿既有隧道正洞施工,保证其结构安全和沉降满足要求奠定了理论基础,该成果可为类似下穿隧道工程和小距离隧道工程爆破振动控制提供参考。

Research on Blasting Vibration Response of Existing Tunnels

In order to ensure the safety of the existing tunnels and the impact of blasting vibration response under the excavation of the tunnel,the excavation blasting of Xiaogaoshan high-speed railway tunnel in Guizhou segment of Shanghai-Kunming passenger dedicated line was taken as an example.The influence of blasting vibration response was studied based on the robust regression and wavelet packet analysis techniques.The sandstone buffer layer was set up in the tunnel with existing tunnels,and the behavior and propagation mechanism of the blasting seismic wave in the tunnel construction were explored.Results show that the main frequency distribution was wide,and the buffer lay-er effectively absorbed most of the high frequency band energy.The energy in the existing tunnel structure was mainly concentrated between the second to fourth frequency bands,and the peak value of the vibration velocity was reduced about 34% The main vibration frequency in each direction was mainly between the middle and low frequency range of 5 70 Hz;the tangential direction energy occupied the main advantage,which should be paid great attention.The study provides a theoretical basis for the construction of the existing tunnel and the structural safety.