CAJ | 학술논문

在刚性材料试验压力机上对花岗岩、灰岩、红砂岩、砂岩、千枚岩及泥岩6种典型的岩石试样进行了单轴全过程加载试验,通过自主研制的数字化次声波探测系统对加载过程中的岩石破裂发射出的次声波信号进行了实时探测.为了研究岩石微破裂过程是否存在发射低频次声波现象及其频率分布等特性,通过小波阈值去噪、短时傅立叶变换(STFT)时-频分析和时域累计振铃计数的方法对数字次声波信号进行了处理与分析.研究结果表明:①岩石在破坏前加载过程中存在明显的发射次声波现象;②岩石破裂产生突出次声信号的频率主要分布在2.0~6.0 Hz之间;③在结构较完整的情况下,硬岩(如花岗岩、灰岩)在变形破裂过程中产生的次声信号数量要比软岩(如泥岩)多.与一般声波相比,因次声波具有不容易衰减,不易被水和空气吸收,波长很长可绕开大型障碍物等独特性质,结合其他方法对岩石破裂产生次声波现象的进一步研究可为岩石(体)稳定性监测提供重要的研究方法和技术手段.
재강성재료시험압력궤상대화강암、회암、홍사암、사암、천매암급니암6충전형적암석시양진행료단축전과정가재시험,통과자주연제적수자화차성파탐측계통대가재과정중적암석파렬발사출적차성파신호진행료실시탐측.위료연구암석미파렬과정시부존재발사저빈차성파현상급기빈솔분포등특성,통과소파역치거조、단시부립협변환(STFT)시-빈분석화시역루계진령계수적방법대수자차성파신호진행료처리여분석.연구결과표명:①암석재파배전가재과정중존재명현적발사차성파현상;②암석파렬산생돌출차성신호적빈솔주요분포재2.0~6.0 Hz지간;③재결구교완정적정황하,경암(여화강암、회암)재변형파렬과정중산생적차성신호수량요비연암(여니암)다.여일반성파상비,인차성파구유불용역쇠감,불역피수화공기흡수,파장흔장가요개대형장애물등독특성질,결합기타방법대암석파렬산생차성파현상적진일보연구가위암석(체)은정성감측제공중요적연구방법화기술수단.
@@@@Experiments on characteristics of infrasonic wave generated by full-regime rock failure under uniaxial loading are carried out with a stiffness material test machine, and the stiffness materials involve granite, limestone, red sandstone, sandstone, phyllite, mudstone. In this study, an advanced digital infrasound emission detecting system to study the characteristics of the infrasonic signals is independently developed. The collected infrasonic signals are processed and analyzed through the wavelet-based denoising method, short-time Fourier transform time-frequency analysis and accumulative ring-down count (ARDC). The results show that: ① The infrasonic wave emission phenomena can apparently appear during the process of uniaxial loading of rocks before rocks fracture. ②The characteristic frequency of prominent infrasonic wave generated by rocks’ fracture typically range 2.0-6.0 Hz. ③ The ARDC of hard rocks, e.g. granite and limestone, are much more than those of soft rocks, e.g. mudstone, in the case of complete structure. Compared with other acoustic signals, infrasound is low-attenuate, cannot be absorbed easily by water and air, and can propagate avoiding huge obstacles due to its long wavelength. Combined with other methods, the further study of the characteristics of infrasonic wave generated by rocks’ microfracture can provide a significant innovate approach and techniques for rock stability monitoring.