隧道掘进爆破振动对围岩影响的HHT分析

为了探究隧道掘进爆破振动信号在围岩等级改变处的传播衰减特性，以新建铁路北京至沈阳客运专线（辽宁段）TJ-1标三棱山隧道为工程背景，采用理论分析与现场试验相结合的方法，基于TC-4850监测试验数据，对爆破质点振速时程曲线进行EMD分解和Hilbert变换。依据测点3个方向的边际谱和瞬时能量谱，分析爆破振动能量在时域和频域的分布规律，进而可以得出各频带的能量百分比以及总能量与距离的关系曲线。通过分析地震波信号沿隧道围岩传播衰减性质可以得出:爆破振动能量在频域上分布具有各向异性，而且在垂直方向上具有数量比例高、所占频带低的特点；隧道掘进爆破振动总能量在围岩等级改变处出现“断崖式”衰减，且在Ⅳ级围岩中相对衰减率更高，衰减更为迅速。

HHT analysis on influence of blasting vibration during tunnel excavation on surrounding rock

In order to explore the propagation attenuation characteristics of blasting vibration signals during tunnel excavation in the grade change area of surrounding rock,the combined method of theoretical analysis and field test was adopted in the engineering background of new passenger line railway from Beijing to Shenyang (Liaoning section) TJ-1 section Sanlengshan tunnel.According to the TC-4850 monitoring test data,the EMD decomposition and Hilbert transform were conducted on the time history curve of blasting particle vibration velocity.Based on the marginal spectrum and instant energy spectrum of measuring point in 3 directions,the distribution laws of blasting vibration energy in time domain and frequency domain were analyzed,and the percentage of energy in each frequency band and the relationship curve between total energy and distance were concluded.The propagation attenuation properties of seismic wave signals along the surrounding rock in tunnel was analyzed,and the results showed that the blasting vibration energy had anisotropy in the frequency domain,and it had the characteristics of high proportion and low occupied frequency band in the vertical direction.The attenuation law of tunnel excavation blasting vibration total energy in the grade change area of surrounding rock was “bluff” style,and the relative attenuation rate was higher and the attenuation was faster in the grade Ⅳ surrounding rock.