Deng Zuhua, Meng Junyu, Deng Yongfeng, Ni Junjun, Ye Daicheng
Institute of Geotechnical Engineering, School of Transportation, Southeast University, Nanjing, 211189, China.
Jiangsu Key Laboratory of Low Carbon and Sustainable Geotechnical Engineering, Southeast University, Nanjing, 211189, China.
Sci Rep. 2024 Sep 19;14(1):21909. doi: 10.1038/s41598-024-73089-1.
This study aims to analyze the vibration signals near the ground surface due to the underneath drilling and blasting activities in a fissured rock tunnel. Blasting induced vibration on the ground surface was continuously monitored in a fissured rock tunnel drilling and blasting excavation project in field. Wavelet packet analysis of the vibration signals using Matlab was carried out for signal denoising, differential blasting delay time interval identification, and three-way time-frequency energy analysis. The results show that within a 30 m range from the palm face, the dominant frequency bands of blasting-induced vibrations on the ground surface were concentrated in the range of 0-130 Hz. Two prominent peak frequency bands were identified at 31.25-39.063 Hz (low-frequency band) and 93.75-101.56 Hz (high-frequency band), accounting for 12% of the total energy. Among the three directions of ground surface vibrations, the energy decay was the most significant in the x-direction (tunnel excavation direction), which amounted to 54.29% of the overall energy decay with increasing distance. The energy decay within the 50-80 Hz range was the most pronounced (more than 90%), when the angle between the vibration propagation direction and the fissure or joint direction was 75°. The conclusions provide the insights in the attenuation of blast-induced vibrations in fissured rock and can potentially assist in the design of blasting vibration control.
本研究旨在分析裂隙岩石隧道中地下钻孔和爆破活动引起的地表附近振动信号。在某裂隙岩石隧道钻孔爆破开挖工程现场，对地表爆破诱发振动进行了连续监测。利用Matlab对振动信号进行小波包分析，以进行信号去噪、微差爆破延迟时间间隔识别和三维时频能量分析。结果表明，在掌子面30m范围内，地表爆破诱发振动的主频带集中在0 - 130Hz范围内。识别出两个突出的峰值频带，分别为31.25 - 39.063Hz（低频带）和93.75 - 101.56Hz（高频带），占总能量的12%。在地表振动的三个方向中，x方向（隧道开挖方向）的能量衰减最为显著，随着距离增加，其能量衰减占总能量衰减的54.29%。当振动传播方向与裂隙或节理方向的夹角为75°时，50 - 八十Hz范围内的能量衰减最为明显（超过90%）。研究结论为裂隙岩石中爆破诱发振动的衰减提供了见解，并可能有助于爆破振动控制设计。
