作　　者： (闫长斌）;

机构地区： 郑州大学土木工程学院,河南郑州450001

出　　处： 《岩土力学》 2017年第9期2721-2727,2745,共8页

摘　　要： 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。 This study is to reveal internal relationships between cumulative damage effects of rock blasting and acoustic variation characters of rock mass.In this study,a small dose of blasting was conducted for ten times on the surrounding rock in underground engineering.Then in-situ acoustic measurement was carried out to analyze the corresponding damage of rock mass.Based on the fast Fourier transform（FFT）,attenuation characteristics of the acoustic wave were discussed when propagating in rock mass with blasted damage.Meanwhile,this study also investigated the effect of blasting times on variation laws of acoustic parameters of rock mass,such as the dominant frequency and maximum amplitude in the frequency domain.In addition,the influence factors,for example,the thickness of the broken zone,the distance between transducers,the distance from the explosive source,were all analyzed as well.Research results show that high-frequency components of acoustic signals were absorbed gradually with increasing and extending blasting rock cracks,while the proportion of low-frequency components grew up constantly with the addition of blasting times.At the same time,the dominant frequency was shifted in the low-frequency direction.Furthermore,the distortion degree of frequency spectrum curves increased.It is found that both the dominant frequency ratio and the maximum amplitude ratio in the frequency domain declined nonlinearly.Moreover,the latter was more sensitive to blasting damage than the former.The variability of rock mass frequency spectrum became weakening with increasing the distance from the explosive source.The increase of the dominant frequency and the attenuation of the maximum amplitude in the frequency domain were substantially significant with the increase of the distance between transducers.Therefore,this study provides a valuable reference to enrich and improve the acoustic method for cumulative damage effects of rock mass blasting.

关 键 词： 岩石力学 爆破损伤 累积效应 声波测试 频谱特征 快速傅立叶变换