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为深入揭示岩体爆破累积损伤效应及其与岩体声学特性之间的内在联系,在某地下工程围岩中进行了10次小药量爆破,并开展了岩体损伤现场声波测试。基于快速傅立叶变换(FFT),探讨了声波在爆破损伤岩体中传播时的衰减特性,分析了声波主频、频域内最大振幅等岩体声学参数随爆破次数不断增加的变化特性,同时探讨了围岩松动圈厚度、声波换能器间距、爆心距等因素的影响。研究结果表明,随爆破次数增加,岩体爆生裂隙不断增加和扩展,声波信号中的高频成分不断被吸收,低频成分所占比例增加,主频向低频方向偏移,频谱曲线畸变程度增加;声波主频比和频域最大振幅比均呈非线性降低趋势,频域最大振幅比对岩体爆破损伤的敏感性高于声波主频比;随爆心距增大,岩体声波频谱变化程度逐渐减弱。声波换能器间距越大,声波主频变化越大,频域内最大振幅衰减变化越显著。研究成果对于丰富和完善岩体爆破累积损伤效应声学研究方法具有一定的参考意义。
In order to reveal the cumulative damage effect of rock mass blasting and its inherent relationship with the acoustic characteristics of rock mass, 10 small-quantity explosions were carried out in the surrounding rock of a subsurface project, and the on-site acoustic wave test of rock mass damage was carried out. Based on Fast Fourier Transform (FFT), the attenuation characteristics of sound waves propagating in blasting damaged rock mass are discussed. The changing characteristics of rock acoustic parameters with increasing frequency of blasting, such as dominant frequency of sound wave and maximum amplitude in frequency domain, are analyzed. The thickness of surrounding rock loose ring, the distance between acoustic wave transducers and the distance between burst cores and other factors. The results show that with the increase of the number of blasting, the crevice of rock bursts increases and expands continuously. The high frequency components of the acoustic wave signal are absorbed continuously, the proportion of low frequency components increases, the main frequency shifts to low frequency, and the distortion of spectrum curve increases ; The main frequency ratio of sound wave and the maximum amplitude ratio in the frequency range all showed a non-linear decreasing trend. The maximum amplitude ratio in the frequency band was more sensitive to the blasting damage than the main frequency ratio. With the increase of the burst center distance, Gradually weakened. The greater the acoustic transducer spacing, the greater the change of the dominant frequency of the sound wave, the more significant the change of the maximum amplitude attenuation in the frequency domain. The research results have some reference significance for enriching and improving the acoustic study method of cumulative damage effect of rock mass blasting.