摘要
通过岩石力学室内加载试验,对花岗岩在不同围压下的破坏全过程进行声发射试验,得到岩石破裂全过程中的力学参数和声发射低频、高频信号特征,研究低频、高频声发射信号的振铃计数、能量累计数与岩石应力、时间之间的关系,探求声发射信号峰值频率在岩石主破裂前期的分布情况。研究结果表明:低频与高频通道接收的声发射信号基本特征——振铃计数、能量累计数在岩石破裂过程中的整体变化趋势基本相同,与岩石力学过程形成良好的对应;两通道的信号基本特征主要区别在于数值大小。在声发射频谱特征方面,岩石破裂的前兆信息在声发射信号峰值频率分布中呈现为峰频主频段增多的特征,表现为信号峰频分布由岩石加载初期的1~2个主频段(40~50和150~170 k Hz频段)在岩石临界主破裂时增多到最多5个主频段(25~30,40~50,60~70,90~100和150~160 k Hz频段)。
Laboratory experiments on the characteristics of acoustic emission(AE) in two frequency channels in the full failure process of granite specimens under different confining pressures were carried out. The mechanical properties and AE characteristics in low and high frequencies of granite were obtained. The relationships of AE ringing counts,AE accumulative energy,stress with the time were analyzed. The distributions of peak frequencies of AE signals before the major fracturing of the granite were studied in detail. The basic characteristics of AE in the low and high frequencies are similar during the granite failure,which matches well with the mechanical properties. The main difference between the basic characteristics of AE in the low and high frequency channels is the magnitude of the numerical values. In the aspect of spectrum signatures of AE,the number of the concentrated ranges of peak frequency of AE was increased from 2(40–50 and 150–170 k Hz) in the initial loading period to 5(25–30,40–50,60–70,90–100 and 150–160 k Hz) in the period just before the major cracking of rock.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2015年第4期694-702,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51174015)
国家重点基础发展计划(973)项目(2010CB226803
2010CB731501)
关键词
岩石力学
声发射
频率特征
前兆信息
rock mechanics
acoustic emission(AE)
frequency characteristics
fracture precursors
