地铁隧道爆破振动测试及时频特征分析

为确保某市地铁隧道安全、高效地爆破开挖，采用网络测振仪测试了隧道掘进爆破时周边建(构)筑物的爆破振速。基于频率切片小波变换开展时频特征分析，首先得到了测振信号的全频带时频分布特征，进而通过5个主成分频率切片区间更进一步精确提取了爆破振动信号时域、频域分布特征，并得到了相应频带内的爆破振动重构分量。实测数据时频特征分析表明，频率切片小波变换具备独特的信号分析优势，适用于地铁爆破振动信号时频特征提取；此次地铁隧道钻爆法开挖产生的质点峰值振速在0.07～0.85 cm/s之间，主频在13.3～68.9 Hz之间，爆破振速处于《爆破安全规程》规定的安全阈值范围内，爆破方案基本合理。

Analysis of Time-Frequency Characteristics in Blasting Vibration Test of Subway Tunnel

To ensure safe and efficient blasting excavation of subway tunnel in a city, vibration velocity of surrounding buildings (structures) during tunnel excavation blasting was measured by network vibration meter. Time-frequency characteristic analysis based on frequency slice wavelet transform was carried out to obtain distribution characteristics of vibration signal for the whole band. Then, the time-domain and frequency-domain distribution characteristics of the blasting vibration signal were further accurately extracted through the main component frequency slice interval, and the reconstruction components of the blasting vibration in the corresponding frequency band were obtained. Time-frequency characteristic analysis of the measured data shows that the frequency slice wavelet transform has unique signal analysis advantages and is suitable for the extraction of the time-frequency characteristic of the blasting vibration signal of the subway. The particles produced by drilling and blasting excavation of subway tunnel are featured by a peak vibration velocity within the range of 0.07-0.85 cm/s, a main frequency among 13.3-68.9 Hz, and a blasting vibration in conformance to the safety threshold specified in Blasting Safety Regulations. The blasting scheme is basically reasonable.